U.S. flag

An official website of the United States government

Here’s how you know

Official websites use .gov

A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS

A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

StopBullying.gov

How to Prevent Bullying

Print

Parents, school staff, and other caring adults have a role to play in preventing bullying. They can: 

  • Help kids understand bullying. Talk about what bullying is and how to stand up to it safely. Tell kids bullying is unacceptable. Make sure kids know how to get help.
  • Keep the lines of communication open . Check in with kids often. Listen to them. Know their friends, ask about school, and understand their concerns.
  • Encourage kids to do what they love. Special activities, interests, and hobbies can boost confidence, help kids make friends, and protect them from bullying behavior.
  • Model how to treat others with kindness and respect.

Help Kids Understand Bullying

Kids who know  what bullying is can better identify it. They can talk about bullying if it happens to them or others. Kids need to know ways to safely stand up to bullying and how to get help.

  • Encourage kids to speak to a trusted adult if they are bullied or see others being bullied. The adult can give comfort, support, and advice, even if they can’t solve the problem directly. Encourage the child to  report bullying  if it happens.
  • Talk about  how to stand up to kids who bully . Give tips, like using humor and saying “stop” directly and confidently. Talk about what to do if those actions don’t work, like walking away
  • Talk about strategies for staying safe, such as staying near adults or groups of other kids.
  • Urge them to help kids who are bullied  by showing kindness or getting help.
  • Watch the short webisodes and discuss them - PDF with kids.

Keep the Lines of Communication Open

Research tells us that children really do look to parents and caregivers for advice and help on tough decisions. Sometimes spending 15 minutes a day talking can reassure kids that they can talk to their parents if they have a problem. Start conversations about daily life and feelings with questions like these:

  • What was one good thing that happened today? Any bad things?
  • What is lunch time like at your school? Who do you sit with? What do you talk about?
  • What is it like to ride the school bus?
  • What are you good at? What would do you like best about yourself?

Talking about bullyin g directly is an important step in understanding how the issue might be affecting kids. There are no right or wrong answers to these questions, but it is important to encourage kids to answer them honestly. Assure kids that they are not alone in addressing any problems that arise. Start conversations about bullying with questions like these:

  • What does “bullying” mean to you?
  • Describe what kids who bully are like. Why do you think people bully?
  • Who are the adults you trust most when it comes to things like bullying?
  • Have you ever felt scared to go to school because you were afraid of bullying? What ways have you tried to change it?
  • What do you think parents can do to help stop bullying?
  • Have you or your friends left other kids out on purpose? Do you think that was bullying? Why or why not?
  • What do you usually do when you see bullying going on?
  • Do you ever see kids at your school being bullied by other kids? How does it make you feel?
  • Have you ever tried to help someone who is being bullied? What happened? What would you do if it happens again?

Get more ideas for talking with children - PDF about life and about bullying. If concerns come up,  be sure to respond .

There are simple ways that parents and caregivers can keep up-to-date with kids’ lives. 

  • Read class newsletters and school flyers. Talk about them at home.
  • Check the school website
  • Go to school events
  • Greet the bus driver
  • Meet teachers and counselors at “Back to School” night or reach out by email
  • Share phone numbers with other kids’ parents

Teachers and school staff also have a role to play. 

Encourage Kids to Do What They Love

Help kids take part in activities, interests, and hobbies they like. Kids can volunteer, play sports, sing in a chorus, or join a youth group or school club. These activities give kids a chance to have fun and meet others with the same interests. They can build confidence and friendships that help protect kids from bullying.

Model How to Treat Others with Kindness and Respect

Kids learn from adults’ actions. By treating others with kindness and respect, adults show the kids in their lives that there is no place for bullying. Even if it seems like they are not paying attention, kids are watching how adults manage stress and conflict, as well as how they treat their friends, colleagues, and families.

Fast Facts: Preventing Bullying

Bullying is a form of youth violence and an adverse childhood experience  (ACE). CDC defines bullying as any unwanted aggressive behavior(s) by another youth or group of youths, who are not siblings or current dating partners, that involves an observed or perceived power imbalance, and is repeated multiple times or is highly likely to be repeated. Bullying may inflict harm or distress on the targeted youth including physical, psychological, social, or educational harm. Common types of bullying include:

  • Physical such as hitting, kicking, and tripping
  • Verbal including name-calling and teasing
  • Relational/social such as spreading rumors and leaving out of the group
  • Damage to property of the victim

Bullying can also occur through technology, which is called electronic bullying or cyberbullying. A young person can be a perpetrator, a victim, or both (also known as “bully/victim”). For more information about bullying definitions please see Bullying Surveillance Among Youths: Uniform Definitions for Public Health and Recommended Data Elements, Version 1 [8.64 MB, 116 Pages, 508] .

Bullying is widespread in the United States. Bullying negatively impacts all youth involved including those who are bullied, those who bully others, and those who witness bullying, known as bystanders.

  • Bullying is common . About 1 in 5 high school students reported being bullied on school property. More than 1 in 6 high school students reported being bullied electronically in the last year.
  • Some youth experience bullying more than others . Nearly 40% of high school students who identify as lesbian, gay, or bisexual and about 33% of those who were not sure of their sexual identity experienced bullying at school or electronically in the last year, compared to 22% of heterosexual high school students. About 30% of female high school students experienced bullying at school or electronically in the last year, compared to about 19% of males. Nearly 29% of White high school students experienced bullying at school or electronically in the last year compared to about 19% of Hispanic and 18% of Black high school students.
  • Bullying is a frequent discipline problem . Nearly 14% of public schools report that bullying is a discipline problem occurring daily or at least once a week.
  • Reports of bullying are highest in middle schools (28%) followed by high schools (16%), combined schools (12%), and primary schools (9%).
  • Reports of cyberbullying are highest in middle schools (33%) followed by high schools (30%), combined schools (20%), and primary schools (5%).

bullying how big is the problem

Bullying can result in physical injury, social and emotional distress, self-harm, and even death. It also increases the risk for depression, anxiety, sleep difficulties, lower academic achievement, and dropping out of school. Youth who bully others are at increased risk for substance misuse, academic problems, and experiencing violence later in adolescence and adulthood. Youth who bully others and are bullied themselves suffer the most serious consequences and are at greater risk for mental health and behavioral problems.

Bullying is preventable. There are many factors that may increase or decrease the risk for perpetrating or experiencing bullying. To prevent bullying, we must understand and address the factors that put people at risk for or protect them from violence . CDC developed, Youth Violence Prevention Resource for Action [4 MB, 64 Pages] , to help communities take advantage of the best available evidence to prevent youth violence. This resource is also  Cdc-pdf available in Spanish [3.89 MB, 68 Pages, 508] and can be used as a tool in efforts to impact individual behaviors as well as the relationship, family, school, community, and societal risk and protective factors for violence. The approaches in this resource, particularly universal school-based programs that strengthen youths’ skills and modify the physical and social environment, have been shown to reduce violence and bullying or key risk factors.

Different types of violence are connected and often share root causes. Bullying is linked to other forms of violence through shared risk and protective factors . Addressing and preventing one form of violence may have an impact on preventing other forms of violence.

How can we stop teen dating violence it before it starts

See Youth Violence Resources for articles, publications, data sources, and prevention resources for bullying.

  • Gladden RM, Vivolo-Kantor AM, Hamburger ME, Lumpkin CD. Bullying surveillance among youths: Uniform definitions for public health and recommended data elements, Version 1.0. Atlanta, GA; National Center for Injury Prevention and Control, Centers for Disease Control and Prevention and U.S. Department of Education; 2013. Available from https://www.cdc.gov/violenceprevention/pdf/bullying-definitionsfinal-a.pdf.
  • Centers for Disease Control and Prevention. Youth risk behavior surveillance—United States, 2019. Morbidity and Mortality Weekly Report–Surveillance Summaries 2020; 69(SS1). Available from https://www.cdc.gov/healthyyouth/data/yrbs/pdf/2019/su6901-H.pdf
  • Diliberti, M., Jackson, M., Correa, S., and Padgett, Z. (2019). Crime, Violence, Discipline, and Safety in U.S. Public Schools: Findings From the School Survey on Crime and Safety: 2017–18 (NCES 2019-061). U.S. Department of Education. Washington, DC: National Center for Education Statistics. Retrieved from http://nces.ed.gov/pubsearch .
  • Farrington D, Baldry A. Individual risk factors for school bullying. Journal of Aggression, Conflict and Peace Research 2010; 2(1):4-16. Available from https://doi.org/10.5042/jacpr.2010.0001.
  • David-Ferdon, C., Vivolo-Kantor, A. M., Dahlberg, L. L., Marshall, K. J., Rainford, N. & Hall, J. E. (2016). Youth Violence Prevention Resource for Action: A Compilation of the Best Available Evidence. Atlanta, GA: National Center for Injury Prevention and Control, Centers for Disease Control and Prevention.  Note: The title of this document was changed in July 2023 to align with other Prevention Resources being developed by CDC’s Injury Center. The document was previously cited as “A Comprehensive Technical Package for the Prevention of Youth Violence and Associated Risk Behaviors.”

To receive email updates about this page, enter your email address:

  • Data & Statistics (WISQARS)
  • Opioid Overdose Prevention
  • Traumatic Brain Injury
  • Motor Vehicle Safety

Exit Notification / Disclaimer Policy

  • The Centers for Disease Control and Prevention (CDC) cannot attest to the accuracy of a non-federal website.
  • Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website.
  • You will be subject to the destination website's privacy policy when you follow the link.
  • CDC is not responsible for Section 508 compliance (accessibility) on other federal or private website.

Greater Good Science Center • Magazine • In Action • In Education

Education Articles & More

What are the best ways to prevent bullying in schools, a new study identifies the most effective approaches to bullying prevention..

All 50 U.S. states require schools to have a bullying prevention policy.

But a policy, alone, is not enough. Despite the requirement, there’s been a slight uptick in all forms of bullying during the last three years. Bullying can look like experienced basketball players systematically intimidating novice players off the court, kids repeatedly stigmatizing immigrant classmates for their cultural differences, or a middle-school girl suddenly being insulted and excluded by her group of friends.

Bullying occurs everywhere, even in the highest-performing schools, and it is hurtful to everyone involved, from the targets of bullying to the witnesses—and even to bullies themselves. October is National Bullying Prevention Month, so it’s a good time to ask ourselves: What are the best practices for preventing bullying in schools? That’s a question I explored with my colleague Marc Brackett from the Yale Center for Emotional Intelligence, in a recent paper that reviewed dozens of studies of real-world bullying prevention efforts.

essay on prevention of bullying

As we discovered, not all approaches to bullying prevention are equally effective. Most bullying prevention programs focus on raising awareness of the problem and administering consequences. But programs that rely on punishment and zero tolerance have not been shown to be effective in the U.S.; and they often disproportionately target students of color. Programs like peer mediation that place responsibility on the children to work out conflicts can increase bullying. (Adult victims of abuse are never asked to “work it out” with their tormentor, and children have an additional legal right to protections due to their developmental status.) Bystander intervention, even among adults, only works for some people—extroverts, empaths, and people with higher social status and moral engagement. Many approaches that educators adopt have not been evaluated through research; instead, educators tend to select programs based on what their colleagues use.

We found two research-tested approaches that show the most promise for reducing bullying (along with other forms of aggression and conflict). They are a positive school climate, and social and emotional learning.

Building a positive school climate

School climate can be difficult to define, though possible to measure . It is the “felt sense” of being in a school, which can arise from a greeting, the way a problem is resolved, or how people work together; it is a school’s “heart and soul,” its “quality and character.” Schools with a positive climate foster healthy development, while a negative school climate is associated with higher rates of student bullying, aggression, victimization, and feeling unsafe.

GGSC Online Courses for Educators

GGSC Online Courses for Educators

A suite of practical, self-paced courses to help build kinder, happier schools

The elements of a positive climate may vary, but may often include norms about feelings and relationships, power and how it is expressed, and media consumption. Social norm engineering is a conscious process that builds a positive culture among student peers and school adults that becomes self-reinforcing. Like a healthy immune system, a positive school climate promotes optimal health and reduces the chances of dysfunction or disease.

Leadership is key to a positive climate. Is bullying minimized as a “normal rite of childhood,” or is it recognized as the harmful peer abuse that it is? Do leaders understand that uninterrupted, severe bullying can confer lifelong negative consequences on targets of bullies, bullies, and witnesses? Are school leaders committed to promoting all children’s positive psychological health, or do they over-rely on punishing misbehavior? Can they discern between typical developmental processes that need guidance versus bullying that needs assertive intervention? Are educators empathic to their students, and do they value children’s feelings?

Next, are teachers prepared to deal with bullying? Students consistently report that teachers miss most incidents of bullying and fail to help students when asked. A majority of teachers report that they feel unprepared to deal with classroom bullying. Some teachers bully students themselves , or show a lack of empathy toward children who are bullied. Teachers report that they receive little guidance in “classroom management,” and sometimes default to the disciplinary strategies they learned in their own families growing up.

However, reforming school climate should involve all stakeholders—students and parents, as well as the administrators and teachers—so a school’s specific issues can be addressed, and the flavor of local cultures retained. School climate assessments can be completed periodically to track the impact of improvements.

Advancing social and emotional learning

Social and emotional learning (SEL) is well known, and involves teaching skills of self-awareness, self-management, social awareness, responsible decision making, and relationships management. (Full disclosure: Brackett and I are affiliated with the SEL program RULER .)

Evidence-based SEL approaches have been shown to deliver cost-effective, solid results. Numerous meta-analyses , research reviews , and individual studies of hundreds of thousands of K-12 students show that SEL improves emotional well-being, self-regulation, classroom relationships, and kind and helpful behavior among students. It reduces a range of problems like anxiety, emotional distress, and depression; reduces disruptive behaviors like conflicts, aggression, bullying, anger, and hostile attribution bias ; and it improves academic achievement, creativity, and leadership.

A study of 36 first-grade teachers showed that when teachers were more emotionally supportive of students, children were less aggressive and had greater behavioral self-control, compared to the use of behavior management, which did not improve student self-control. One meta-analysis showed that developing emotional competence was protective against becoming a victim of bullying; social competence and academic performance were protective against becoming a bully; and positive peer interactions were protective against becoming a bully-victim (one who has been bullied and bullies others). A series of longitudinal studies showed positive effects into midlife (e.g., fewer divorces, less unemployment) and even cross-generational effects of early SEL. Compared to a matched control group, the children of the adults who participated in the Perry Preschool Project had less criminal involvement and higher educational and employment achievement. A cost-benefit analysis of six SEL programs found them to be good investments, with $11 saved for every $1 spent.

Teachers also benefit from SEL. Those with emotional and social skills training have higher job satisfaction and less burnout, show more positive emotions toward their students, manage their classrooms better, and use more strategies that cultivate creativity, choice, and autonomy in their students. Teachers report that they want more SEL support to cultivate their own emotional and social skills, and to better understand their students’ feelings. But few teacher training programs focus on growing the teachers’ emotion regulation skills.

Bullying at different age levels

SEL approaches should be developmentally wise , since what is salient and possible for children changes at different ages.

For example, preschoolers are expelled from school at the highest rates of all, but the neurological hardware for their self-control is only just developing. Only then are the connections between the emotion circuitry and the more thinking regions of the prefrontal cortex beginning to be myelinated (insulated for faster connectivity), something that will take until the mid 20s to complete. An SEL program like PATHS or RULER that teaches young children language for feelings, and strategies for thinking before acting, can develop better self-regulation.

Online resources on bullying

Learn more about SEL programs .

Read your state’s legislation and policies on bullying .

Read your state’s legislation and policies on cyberbullying .

Schools can refer to this summary of legal issues on bullying .

Many states have laws that outlaw sexting, and most states outlaw revenge porn. Find out your state laws .

Discover tip sheets for preventing and responding to cyberbullying in middle and high school educators, parents, and teens.

Discover more tip sheets for parents and teens .

Sometimes, adults confuse normal developmental processes with bullying. For example, children begin to reorganize their friendships midway through elementary school, something that can naturally create hurt feelings and interpersonal conflict. It should not be misconstrued as bullying, though, which involves intentional, repeated aggression within an imbalance of power. Normal development also includes experimenting with power, and these normal dynamics should be guided safely toward developing a healthy sense of agency, rather than a hurtful exertion of power over someone else.

Finally, the onset of puberty marks the beginning of heightened sensitivity to social relationships, an especially important time to cultivate skills for kinder, gentler relationships. Unfortunately, this is the period when bullying spikes the highest. And while some strategies work well for younger children (for example, advising them to “tell a trusted adult”), this option may fail with teens, and the breakpoint seems to be around the eighth grade. Older teens require approaches that are less didactic and leverage their need for autonomy, while affirming their values and search for meaning. Physiologically, the brain changes during puberty confer a second chance for recalibrating their stress regulation system. That opportunity should be constructively seized.

Approaches should also take into account individual differences between children. Even SEL programs can stumble here, over-relying on just one or two emotion regulation strategies, like breathing or mindfulness. But children vary in their temperaments, sensitivities, strengths, and vulnerabilities. The best SEL approaches guide students toward discovering strategies that work best for them—strategies that are emotion- and context-specific, personalized, and culturally responsive. This approach requires unconventional flexibility on the part of the educators.

And, finally, approaches work best if they are not standalone pedagogies or from kits that end up in the classroom closet at the end of the year. In order to be effective, skills should become fully embedded across the curricula and the entire day, in all settings, and implemented by all adults—in other words, infiltrating the ecosystem. Only approaches used and taught as intended are successful.

Schools can’t do this alone

Families matter, too. Bullying in schools sometimes arises from harsh parenting practices or sibling bullying at home.

Even parents’ workplaces matter. Adults experience bullying in their workplaces at about the same rate as children in schools, and it’s even found among teachers and in senior living communities . In other words, bullying is not just a childhood problem; it is a pervasive human problem. And children are not buffered from the wider social world—bullying of children who belong to groups targeted in the national political discourse has spiked on playgrounds nationwide.

Ultimately, we need a substantial shift in our mindsets about the importance of children and their feelings. Children are more likely to thrive when we nurture their humanity, and offer them language and strategies and values to help them identify, express, and, thus, regulate their feelings. When parents, teachers, and administrators gain new awareness into the complex roots of bullying and adopt new strategies for addressing it, schools can lead the way. The kids are counting on us.

Courage in Education: Facing Challenges with Strength, Determination, and Hope

Courage in Education: Facing Challenges with Strength, Determination, and Hope

A new online course to help educators cultivate courage in schools and classrooms.

About the Author

Diana divecha.

Diana Divecha, Ph.D. , is a developmental psychologist, an assistant clinical professor at the Yale Child Study Center and Yale Center for Emotional Intelligence, and on the advisory board of the Greater Good Science Center. Her blog is developmentalscience.com .

You May Also Enjoy

Playground Heroes

This article — and everything on this site — is funded by readers like you.

Become a subscribing member today. Help us continue to bring “the science of a meaningful life” to you and to millions around the globe.

National Academies Press: OpenBook

Preventing Bullying Through Science, Policy, and Practice (2016)

Chapter: 1 introduction, 1 introduction.

Bullying, long tolerated by many as a rite of passage into adulthood, is now recognized as a major and preventable public health problem, one that can have long-lasting consequences ( McDougall and Vaillancourt, 2015 ; Wolke and Lereya, 2015 ). Those consequences—for those who are bullied, for the perpetrators of bullying, and for witnesses who are present during a bullying event—include poor school performance, anxiety, depression, and future delinquent and aggressive behavior. Federal, state, and local governments have responded by adopting laws and implementing programs to prevent bullying and deal with its consequences. However, many of these responses have been undertaken with little attention to what is known about bullying and its effects. Even the definition of bullying varies among both researchers and lawmakers, though it generally includes physical and verbal behavior, behavior leading to social isolation, and behavior that uses digital communications technology (cyberbullying). This report adopts the term “bullying behavior,” which is frequently used in the research field, to cover all of these behaviors.

Bullying behavior is evident as early as preschool, although it peaks during the middle school years ( Currie et al., 2012 ; Vaillancourt et al., 2010 ). It can occur in diverse social settings, including classrooms, school gyms and cafeterias, on school buses, and online. Bullying behavior affects not only the children and youth who are bullied, who bully, and who are both bullied and bully others but also bystanders to bullying incidents. Given the myriad situations in which bullying can occur and the many people who may be involved, identifying effective prevention programs and policies is challenging, and it is unlikely that any one approach will be ap-

propriate in all situations. Commonly used bullying prevention approaches include policies regarding acceptable behavior in schools and behavioral interventions to promote positive cultural norms.

STUDY CHARGE

Recognizing that bullying behavior is a major public health problem that demands the concerted and coordinated time and attention of parents, educators and school administrators, health care providers, policy makers, families, and others concerned with the care of children, a group of federal agencies and private foundations asked the National Academies of Sciences, Engineering, and Medicine to undertake a study of what is known and what needs to be known to further the field of preventing bullying behavior. The Committee on the Biological and Psychosocial Effects of Peer Victimization:

Lessons for Bullying Prevention was created to carry out this task under the Academies’ Board on Children, Youth, and Families and the Committee on Law and Justice. The study received financial support from the Centers for Disease Control and Prevention (CDC), the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the Health Resources and Services Administration, the Highmark Foundation, the National Institute of Justice, the Robert Wood Johnson Foundation, Semi J. and Ruth W. Begun Foundation, and the Substance Abuse and Mental Health Services Administration. The full statement of task for the committee is presented in Box 1-1 .

Although the committee acknowledges the importance of this topic as it pertains to all children in the United States and in U.S. territories, this report focuses on the 50 states and the District of Columbia. Also, while the committee acknowledges that bullying behavior occurs in the school

environment for youth in foster care, in juvenile justice facilities, and in other residential treatment facilities, this report does not address bullying behavior in those environments because it is beyond the study charge.

CONTEXT FOR THE STUDY

This section of the report highlights relevant work in the field and, later in the chapter under “The Committee’s Approach,” presents the conceptual framework and corresponding definitions of terms that the committee has adopted.

Historical Context

Bullying behavior was first characterized in the scientific literature as part of the childhood experience more than 100 years ago in “Teasing and Bullying,” published in the Pedagogical Seminary ( Burk, 1897 ). The author described bullying behavior, attempted to delineate causes and cures for the tormenting of others, and called for additional research ( Koo, 2007 ). Nearly a century later, Dan Olweus, a Swedish research professor of psychology in Norway, conducted an intensive study on bullying ( Olweus, 1978 ). The efforts of Olweus brought awareness to the issue and motivated other professionals to conduct their own research, thereby expanding and contributing to knowledge of bullying behavior. Since Olweus’s early work, research on bullying has steadily increased (see Farrington and Ttofi, 2009 ; Hymel and Swearer, 2015 ).

Over the past few decades, venues where bullying behavior occurs have expanded with the advent of the Internet, chat rooms, instant messaging, social media, and other forms of digital electronic communication. These modes of communication have provided a new communal avenue for bullying. While the media reports linking bullying to suicide suggest a causal relationship, the available research suggests that there are often multiple factors that contribute to a youth’s suicide-related ideology and behavior. Several studies, however, have demonstrated an association between bullying involvement and suicide-related ideology and behavior (see, e.g., Holt et al., 2015 ; Kim and Leventhal, 2008 ; Sourander, 2010 ; van Geel et al., 2014 ).

In 2013, the Health Resources and Services Administration of the U.S. Department of Health and Human Services requested that the Institute of Medicine 1 and the National Research Council convene an ad hoc planning committee to plan and conduct a 2-day public workshop to highlight relevant information and knowledge that could inform a multidisciplinary

___________________

1 Prior to 2015, the National Academy of Medicine was known as the Institute of Medicine.

road map on next steps for the field of bullying prevention. Content areas that were explored during the April 2014 workshop included the identification of conceptual models and interventions that have proven effective in decreasing bullying and the antecedents to bullying while increasing protective factors that mitigate the negative health impact of bullying. The discussions highlighted the need for a better understanding of the effectiveness of program interventions in realistic settings; the importance of understanding what works for whom and under what circumstances, as well as the influence of different mediators (i.e., what accounts for associations between variables) and moderators (i.e., what affects the direction or strength of associations between variables) in bullying prevention efforts; and the need for coordination among agencies to prevent and respond to bullying. The workshop summary ( Institute of Medicine and National Research Council, 2014c ) informs this committee’s work.

Federal Efforts to Address Bullying and Related Topics

Currently, there is no comprehensive federal statute that explicitly prohibits bullying among children and adolescents, including cyberbullying. However, in the wake of the growing concerns surrounding the implications of bullying, several federal initiatives do address bullying among children and adolescents, and although some of them do not primarily focus on bullying, they permit some funds to be used for bullying prevention purposes.

The earliest federal initiative was in 1999, when three agencies collaborated to establish the Safe Schools/Healthy Students initiative in response to a series of deadly school shootings in the late 1990s. The program is administered by the U.S. Departments of Education, Health and Human Services, and Justice to prevent youth violence and promote the healthy development of youth. It is jointly funded by the Department of Education and by the Department of Health and Human Services’ Substance Abuse and Mental Health Services Administration. The program has provided grantees with both the opportunity to benefit from collaboration and the tools to sustain it through deliberate planning, more cost-effective service delivery, and a broader funding base ( Substance Abuse and Mental Health Services Administration, 2015 ).

The next major effort was in 2010, when the Department of Education awarded $38.8 million in grants under the Safe and Supportive Schools (S3) Program to 11 states to support statewide measurement of conditions for learning and targeted programmatic interventions to improve conditions for learning, in order to help schools improve safety and reduce substance use. The S3 Program was administered by the Safe and Supportive Schools Group, which also administered the Safe and Drug-Free Schools and Communities Act State and Local Grants Program, authorized by the

1994 Elementary and Secondary Education Act. 2 It was one of several programs related to developing and maintaining safe, disciplined, and drug-free schools. In addition to the S3 grants program, the group administered a number of interagency agreements with a focus on (but not limited to) bullying, school recovery research, data collection, and drug and violence prevention activities ( U.S. Department of Education, 2015 ).

A collaborative effort among the U.S. Departments of Agriculture, Defense, Education, Health and Human Services, Interior, and Justice; the Federal Trade Commission; and the White House Initiative on Asian Americans and Pacific Islanders created the Federal Partners in Bullying Prevention (FPBP) Steering Committee. Led by the U.S. Department of Education, the FPBP works to coordinate policy, research, and communications on bullying topics. The FPBP Website provides extensive resources on bullying behavior, including information on what bullying is, its risk factors, its warning signs, and its effects. 3 The FPBP Steering Committee also plans to provide details on how to get help for those who have been bullied. It also was involved in creating the “Be More than a Bystander” Public Service Announcement campaign with the Ad Council to engage students in bullying prevention. To improve school climate and reduce rates of bullying nationwide, FPBP has sponsored four bullying prevention summits attended by education practitioners, policy makers, researchers, and federal officials.

In 2014, the National Institute of Justice—the scientific research arm of the U.S. Department of Justice—launched the Comprehensive School Safety Initiative with a congressional appropriation of $75 million. The funds are to be used for rigorous research to produce practical knowledge that can improve the safety of schools and students, including bullying prevention. The initiative is carried out through partnerships among researchers, educators, and other stakeholders, including law enforcement, behavioral and mental health professionals, courts, and other justice system professionals ( National Institute of Justice, 2015 ).

In 2015, the Every Student Succeeds Act was signed by President Obama, reauthorizing the 50-year-old Elementary and Secondary Education Act, which is committed to providing equal opportunities for all students. Although bullying is neither defined nor prohibited in this act, it is explicitly mentioned in regard to applicability of safe school funding, which it had not been in previous iterations of the Elementary and Secondary Education Act.

The above are examples of federal initiatives aimed at promoting the

2 The Safe and Drug-Free Schools and Communities Act was included as Title IV, Part A, of the 1994 Elementary and Secondary Education Act. See http://www.ojjdp.gov/pubs/gun_violence/sect08-i.html [October 2015].

3 For details, see http://www.stopbullying.gov/ [October 2015].

healthy development of youth, improving the safety of schools and students, and reducing rates of bullying behavior. There are several other federal initiatives that address student bullying directly or allow funds to be used for bullying prevention activities.

Definitional Context

The terms “bullying,” “harassment,” and “peer victimization” have been used in the scientific literature to refer to behavior that is aggressive, is carried out repeatedly and over time, and occurs in an interpersonal relationship where a power imbalance exists ( Eisenberg and Aalsma, 2005 ). Although some of these terms have been used interchangeably in the literature, peer victimization is targeted aggressive behavior of one child against another that causes physical, emotional, social, or psychological harm. While conflict and bullying among siblings are important in their own right ( Tanrikulu and Campbell, 2015 ), this area falls outside of the scope of the committee’s charge. Sibling conflict and aggression falls under the broader concept of interpersonal aggression, which includes dating violence, sexual assault, and sibling violence, in addition to bullying as defined for this report. Olweus (1993) noted that bullying, unlike other forms of peer victimization where the children involved are equally matched, involves a power imbalance between the perpetrator and the target, where the target has difficulty defending him or herself and feels helpless against the aggressor. This power imbalance is typically considered a defining feature of bullying, which distinguishes this particular form of aggression from other forms, and is typically repeated in multiple bullying incidents involving the same individuals over time ( Olweus, 1993 ).

Bullying and violence are subcategories of aggressive behavior that overlap ( Olweus, 1996 ). There are situations in which violence is used in the context of bullying. However, not all forms of bullying (e.g., rumor spreading) involve violent behavior. The committee also acknowledges that perspective about intentions can matter and that in many situations, there may be at least two plausible perceptions involved in the bullying behavior.

A number of factors may influence one’s perception of the term “bullying” ( Smith and Monks, 2008 ). Children and adolescents’ understanding of the term “bullying” may be subject to cultural interpretations or translations of the term ( Hopkins et al., 2013 ). Studies have also shown that influences on children’s understanding of bullying include the child’s experiences as he or she matures and whether the child witnesses the bullying behavior of others ( Hellström et al., 2015 ; Monks and Smith, 2006 ; Smith and Monks, 2008 ).

In 2010, the FPBP Steering Committee convened its first summit, which brought together more than 150 nonprofit and corporate leaders,

researchers, practitioners, parents, and youths to identify challenges in bullying prevention. Discussions at the summit revealed inconsistencies in the definition of bullying behavior and the need to create a uniform definition of bullying. Subsequently, a review of the 2011 CDC publication of assessment tools used to measure bullying among youth ( Hamburger et al., 2011 ) revealed inconsistent definitions of bullying and diverse measurement strategies. Those inconsistencies and diverse measurements make it difficult to compare the prevalence of bullying across studies ( Vivolo et al., 2011 ) and complicate the task of distinguishing bullying from other types of aggression between youths. A uniform definition can support the consistent tracking of bullying behavior over time, facilitate the comparison of bullying prevalence rates and associated risk and protective factors across different data collection systems, and enable the collection of comparable information on the performance of bullying intervention and prevention programs across contexts ( Gladden et al., 2014 ). The CDC and U.S. Department of Education collaborated on the creation of the following uniform definition of bullying (quoted in Gladden et al., 2014, p. 7 ):

Bullying is any unwanted aggressive behavior(s) by another youth or group of youths who are not siblings or current dating partners that involves an observed or perceived power imbalance and is repeated multiple times or is highly likely to be repeated. Bullying may inflict harm or distress on the targeted youth including physical, psychological, social, or educational harm.

This report noted that the definition includes school-age individuals ages 5-18 and explicitly excludes sibling violence and violence that occurs in the context of a dating or intimate relationship ( Gladden et al., 2014 ). This definition also highlighted that there are direct and indirect modes of bullying, as well as different types of bullying. Direct bullying involves “aggressive behavior(s) that occur in the presence of the targeted youth”; indirect bullying includes “aggressive behavior(s) that are not directly communicated to the targeted youth” ( Gladden et al., 2014, p. 7 ). The direct forms of violence (e.g., sibling violence, teen dating violence, intimate partner violence) can include aggression that is physical, sexual, or psychological, but the context and uniquely dynamic nature of the relationship between the target and the perpetrator in which these acts occur is different from that of peer bullying. Examples of direct bullying include pushing, hitting, verbal taunting, or direct written communication. A common form of indirect bullying is spreading rumors. Four different types of bullying are commonly identified—physical, verbal, relational, and damage to property. Some observational studies have shown that the different forms of bullying that youths commonly experience may overlap ( Bradshaw et al., 2015 ;

Godleski et al., 2015 ). The four types of bullying are defined as follows ( Gladden et al., 2014 ):

  • Physical bullying involves the use of physical force (e.g., shoving, hitting, spitting, pushing, and tripping).
  • Verbal bullying involves oral or written communication that causes harm (e.g., taunting, name calling, offensive notes or hand gestures, verbal threats).
  • Relational bullying is behavior “designed to harm the reputation and relationships of the targeted youth (e.g., social isolation, rumor spreading, posting derogatory comments or pictures online).”
  • Damage to property is “theft, alteration, or damaging of the target youth’s property by the perpetrator to cause harm.”

In recent years, a new form of aggression or bullying has emerged, labeled “cyberbullying,” in which the aggression occurs through modern technological devices, specifically mobile phones or the Internet ( Slonje and Smith, 2008 ). Cyberbullying may take the form of mean or nasty messages or comments, rumor spreading through posts or creation of groups, and exclusion by groups of peers online.

While the CDC definition identifies bullying that occurs using technology as electronic bullying and views that as a context or location where bullying occurs, one of the major challenges in the field is how to conceptualize and define cyberbullying ( Tokunaga, 2010 ). The extent to which the CDC definition can be applied to cyberbullying is unclear, particularly with respect to several key concepts within the CDC definition. First, whether determination of an interaction as “wanted” or “unwanted” or whether communication was intended to be harmful can be challenging to assess in the absence of important in-person socioemotional cues (e.g., vocal tone, facial expressions). Second, assessing “repetition” is challenging in that a single harmful act on the Internet has the potential to be shared or viewed multiple times ( Sticca and Perren, 2013 ). Third, cyberbullying can involve a less powerful peer using technological tools to bully a peer who is perceived to have more power. In this manner, technology may provide the tools that create a power imbalance, in contrast to traditional bullying, which typically involves an existing power imbalance.

A study that used focus groups with college students to discuss whether the CDC definition applied to cyberbullying found that students were wary of applying the definition due to their perception that cyberbullying often involves less emphasis on aggression, intention, and repetition than other forms of bullying ( Kota et al., 2014 ). Many researchers have responded to this lack of conceptual and definitional clarity by creating their own measures to assess cyberbullying. It is noteworthy that very few of these

definitions and measures include the components of traditional bullying—i.e., repetition, power imbalance, and intent ( Berne et al., 2013 ). A more recent study argues that the term “cyberbullying” should be reserved for incidents that involve key aspects of bullying such as repetition and differential power ( Ybarra et al., 2014 ).

Although the formulation of a uniform definition of bullying appears to be a step in the right direction for the field of bullying prevention, there are some limitations of the CDC definition. For example, some researchers find the focus on school-age youth as well as the repeated nature of bullying to be rather limiting; similarly the exclusion of bullying in the context of sibling relationships or dating relationships may preclude full appreciation of the range of aggressive behaviors that may co-occur with or constitute bullying behavior. As noted above, other researchers have raised concerns about whether cyberbullying should be considered a particular form or mode under the broader heading of bullying as suggested in the CDC definition, or whether a separate defintion is needed. Furthermore, the measurement of bullying prevalence using such a definiton of bullying is rather complex and does not lend itself well to large-scale survey research. The CDC definition was intended to inform public health surveillance efforts, rather than to serve as a definition for policy. However, increased alignment between bullying definitions used by policy makers and researchers would greatly advance the field. Much of the extant research on bullying has not applied a consistent definition or one that aligns with the CDC definition. As a result of these and other challenges to the CDC definition, thus far there has been inconsistent adoption of this particular definition by researchers, practitioners, or policy makers; however, as the definition was created in 2014, less than 2 years is not a sufficient amount of time to assess whether it has been successfully adopted or will be in the future.

THE COMMITTEE’S APPROACH

This report builds on the April 2014 workshop, summarized in Building Capacity to Reduce Bullying: Workshop Summary ( Institute of Medicine and National Research Council, 2014c ). The committee’s work was accomplished over an 18-month period that began in October 2014, after the workshop was held and the formal summary of it had been released. The study committee members represented expertise in communication technology, criminology, developmental and clinical psychology, education, mental health, neurobiological development, pediatrics, public health, school administration, school district policy, and state law and policy. (See Appendix E for biographical sketches of the committee members and staff.) The committee met three times in person and conducted other meetings by teleconferences and electronic communication.

Information Gathering

The committee conducted an extensive review of the literature pertaining to peer victimization and bullying. In some instances, the committee drew upon the broader literature on aggression and violence. The review began with an English-language literature search of online databases, including ERIC, Google Scholar, Lexis Law Reviews Database, Medline, PubMed, Scopus, PsycInfo, and Web of Science, and was expanded as literature and resources from other countries were identified by committee members and project staff as relevant. The committee drew upon the early childhood literature since there is substantial evidence indicating that bullying involvement happens as early as preschool (see Vlachou et al., 2011 ). The committee also drew on the literature on late adolescence and looked at related areas of research such as maltreatment for insights into this emerging field.

The committee used a variety of sources to supplement its review of the literature. The committee held two public information-gathering sessions, one with the study sponsors and the second with experts on the neurobiology of bullying; bullying as a group phenomenon and the role of bystanders; the role of media in bullying prevention; and the intersection of social science, the law, and bullying and peer victimization. See Appendix A for the agendas for these two sessions. To explore different facets of bullying and give perspectives from the field, a subgroup of the committee and study staff also conducted a site visit to a northeastern city, where they convened four stakeholder groups comprised, respectively, of local practitioners, school personnel, private foundation representatives, and young adults. The site visit provided the committee with an opportunity for place-based learning about bullying prevention programs and best practices. Each focus group was transcribed and summarized thematically in accordance with this report’s chapter considerations. Themes related to the chapters are displayed throughout the report in boxes titled “Perspectives from the Field”; these boxes reflect responses synthesized from all four focus groups. See Appendix B for the site visit’s agenda and for summaries of the focus groups.

The committee also benefited from earlier reports by the National Academies of Sciences, Engineering, and Medicine through its Division of Behavioral and Social Sciences and Education and the Institute of Medicine, most notably:

  • Reducing Risks for Mental Disorders: Frontiers for Preventive Intervention Research ( Institute of Medicine, 1994 )
  • Community Programs to Promote Youth Development ( National Research Council and Institute of Medicine, 2002 )
  • Deadly Lessons: Understanding Lethal School Violence ( National Research Council and Institute of Medicine, 2003 )
  • Preventing Mental, Emotional, and Behavioral Disorders Among Young People: Progress and Possibilities ( National Research Council and Institute of Medicine, 2009 )
  • The Science of Adolescent Risk-Taking: Workshop Report ( Institute of Medicine and National Research Council, 2011 )
  • Communications and Technology for Violence Prevention: Workshop Summary ( Institute of Medicine and National Research Council, 2012 )
  • Building Capacity to Reduce Bullying: Workshop Summary ( Institute of Medicine and National Research Council, 2014c )
  • The Evidence for Violence Prevention across the Lifespan and Around the World: Workshop Summary ( Institute of Medicine and National Research Council, 2014a )
  • Strategies for Scaling Effective Family-Focused Preventive Interventions to Promote Children’s Cognitive, Affective, and Behavioral Health: Workshop Summary ( Institute of Medicine and National Research Council, 2014b )
  • Investing in the Health and Well-Being of Young Adults ( Institute of Medicine and National Research Council, 2015 )

Although these past reports and workshop summaries address various forms of violence and victimization, this report is the first consensus study by the National Academies of Sciences, Engineering, and Medicine on the state of the science on the biological and psychosocial consequences of bullying and the risk and protective factors that either increase or decrease bullying behavior and its consequences.

Terminology

Given the variable use of the terms “bullying” and “peer victimization” in both the research-based and practice-based literature, the committee chose to use the current CDC definition quoted above ( Gladden et al., 2014, p. 7 ). While the committee determined that this was the best definition to use, it acknowledges that this definition is not necessarily the most user-friendly definition for students and has the potential to cause problems for students reporting bullying. Not only does this definition provide detail on the common elements of bullying behavior but it also was developed with input from a panel of researchers and practitioners. The committee also followed the CDC in focusing primarily on individuals between the ages of 5 and 18. The committee recognizes that children’s development occurs on a continuum, and so while it relied primarily on the CDC defini-

tion, its work and this report acknowledge the importance of addressing bullying in both early childhood and emerging adulthood. For purposes of this report, the committee used the terms “early childhood” to refer to ages 1-4, “middle childhood” for ages 5 to 10, “early adolescence” for ages 11-14, “middle adolescence” for ages 15-17, and “late adolescence” for ages 18-21. This terminology and the associated age ranges are consistent with the Bright Futures and American Academy of Pediatrics definition of the stages of development. 4

A given instance of bullying behavior involves at least two unequal roles: one or more individuals who perpetrate the behavior (the perpetrator in this instance) and at least one individual who is bullied (the target in this instance). To avoid labeling and potentially further stigmatizing individuals with the terms “bully” and “victim,” which are sometimes viewed as traits of persons rather than role descriptions in a particular instance of behavior, the committee decided to use “individual who is bullied” to refer to the target of a bullying instance or pattern and “individual who bullies” to refer to the perpetrator of a bullying instance or pattern. Thus, “individual who is bullied and bullies others” can refer to one who is either perpetrating a bullying behavior or a target of bullying behavior, depending on the incident. This terminology is consistent with the approach used by the FPBP (see above). Also, bullying is a dynamic social interaction ( Espelage and Swearer, 2003 ) where individuals can play different roles in bullying interactions based on both individual and contextual factors.

The committee used “cyberbullying” to refer to bullying that takes place using technology or digital electronic means. “Digital electronic forms of contact” comprise a broad category that may include e-mail, blogs, social networking Websites, online games, chat rooms, forums, instant messaging, Skype, text messaging, and mobile phone pictures. The committee uses the term “traditional bullying” to refer to bullying behavior that is not cyberbullying (to aid in comparisons), recognizing that the term has been used at times in slightly different senses in the literature.

Where accurate reporting of study findings requires use of the above terms but with senses different from those specified here, the committee has noted the sense in which the source used the term. Similarly, accurate reporting has at times required use of terms such as “victimization” or “victim” that the committee has chosen to avoid in its own statements.

4 For details on these stages of adolescence, see https://brightfutures.aap.org/Bright%20Futures%20Documents/3-Promoting_Child_Development.pdf [October 2015].

ORGANIZATION OF THE REPORT

This report is organized into seven chapters. After this introductory chapter, Chapter 2 provides a broad overview of the scope of the problem.

Chapter 3 focuses on the conceptual frameworks for the study and the developmental trajectory of the child who is bullied, the child who bullies, and the child who is bullied and also bullies. It explores processes that can explain heterogeneity in bullying outcomes by focusing on contextual processes that moderate the effect of individual characteristics on bullying behavior.

Chapter 4 discusses the cyclical nature of bullying and the consequences of bullying behavior. It summarizes what is known about the psychosocial, physical health, neurobiological, academic-performance, and population-level consequences of bullying.

Chapter 5 provides an overview of the landscape in bullying prevention programming. This chapter describes in detail the context for preventive interventions and the specific actions that various stakeholders can take to achieve a coordinated response to bullying behavior. The chapter uses the Institute of Medicine’s multi-tiered framework ( National Research Council and Institute of Medicine, 2009 ) to present the different levels of approaches to preventing bullying behavior.

Chapter 6 reviews what is known about federal, state, and local laws and policies and their impact on bullying.

After a critical review of the relevant research and practice-based literatures, Chapter 7 discusses the committee conclusions and recommendations and provides a path forward for bullying prevention.

The report includes a number of appendixes. Appendix A includes meeting agendas of the committee’s public information-gathering meetings. Appendix B includes the agenda and summaries of the site visit. Appendix C includes summaries of bullying prevalence data from the national surveys discussed in Chapter 2 . Appendix D provides a list of selected federal resources on bullying for parents and teachers. Appendix E provides biographical sketches of the committee members and project staff.

Berne, S., Frisén, A., Schultze-Krumbholz, A., Scheithauer, H., Naruskov, K., Luik, P., Katzer, C., Erentaite, R., and Zukauskiene, R. (2013). Cyberbullying assessment instruments: A systematic review. Aggression and Violent Behavior, 18 (2), 320-334.

Bradshaw, C.P., Waasdorp, T.E., and Johnson, S.L. (2015). Overlapping verbal, relational, physical, and electronic forms of bullying in adolescence: Influence of school context. Journal of Clinical Child & Adolescent Psychology, 44 (3), 494-508.

Burk, F.L. (1897). Teasing and bullying. The Pedagogical Seminary, 4 (3), 336-371.

Currie, C., Zanotti, C., Morgan, A., Currie, D., de Looze, M., Roberts, C., Samdal, O., Smith, O.R., and Barnekow, V. (2012). Social determinants of health and well-being among young people. Copenhagen, Denmark: World Health Organization Regional Office for Europe.

Eisenberg, M.E., and Aalsma, M.C. (2005). Bullying and peer victimization: Position paper of the Society for Adolescent Medicine. Journal of Adolescent Health, 36 (1), 88-91.

Espelage, D.L., and Swearer, S.M. (2003). Research on school bullying and victimization: What have we learned and where do we go from here? School Psychology Review, 32 (3), 365-383.

Farrington, D., and Ttofi, M. (2009). School-based programs to reduce bullying and victimization: A systematic review. Campbell Systematic Reviews, 5 (6).

Finkelhor, D., Ormrod, R.K., and Turner, H.A. (2007). Poly-victimization: A neglected component in child victimization. Child Abuse & Neglect , 31 (1), 7-26.

Gladden, R.M., Vivolo-Kantor, A.M., Hamburger, M.E., and Lumpkin, C.D. (2014). Bullying Surveillance among Youths: Uniform Definitions for Public Health and Recommended Data Elements, Version 1.0 . Atlanta, GA: Centers for Disease Control and Prevention and U.S. Department of Education.

Godleski, S.A., Kamper, K.E., Ostrov, J.M., Hart, E.J., and Blakely-McClure, S.J. (2015). Peer victimization and peer rejection during early childhood. Journal of Clinical Child & Adolescent Psychology, 44 (3), 380-392.

Hamburger, M.E., Basile, K.C., and Vivolo, A.M. (2011). Measuring Bullying Victimization, Perpetration, and Bystander Experiences: A Compendium of Assessment Tools. Atlanta, GA: Centers for Disease Control and Prevention, National Center for Injury Prevention and Control.

Hellström, L., Persson, L., and Hagquist, C. (2015). Understanding and defining bullying—Adolescents’ own views. Archives of Public Health, 73 (4), 1-9.

Holt, M.K., Vivolo-Kantor, A.M., Polanin, J.R., Holland, K.M., DeGue, S., Matjasko, J.L., Wolfe, M., and Reid, G. (2015). Bullying and suicidal ideation and behaviors: A meta-analysis. Pediatrics, 135 (2), e496-e509.

Hopkins, L., Taylor, L., Bowen, E., and Wood, C. (2013). A qualitative study investigating adolescents’ understanding of aggression, bullying and violence. Children and Youth Services Review, 35 (4), 685-693.

Hymel, S., and Swearer, S.M. (2015). Four decades of research on school bullying: An introduction. American Psychologist, 70 (4), 293.

Institute of Medicine. (1994). Reducing Risks for Mental Disorders: Frontiers for Preventive Intervention Research. Committee on Prevention of Mental Disorders. P.J. Mrazek and R.J. Haggerty, Editors. Division of Biobehavioral Sciences and Mental Disorders. Washington, DC: National Academy Press.

Institute of Medicine and National Research Council. (2011). The Science of Adolescent Risk-taking: Workshop Report . Committee on the Science of Adolescence. Washington, DC: The National Academies Press.

Institute of Medicine and National Research Council. (2012). Communications and Technology for Violence Prevention: Workshop Summary . Washington, DC: The National Academies Press.

Institute of Medicine and National Research Council. (2014a). The Evidence for Violence Prevention across the Lifespan and around the World: Workshop Summary . Washington, DC: The National Academies Press.

Institute of Medicine and National Research Council. (2014b). Strategies for Scaling Effective Family-Focused Preventive Interventions to Promote Children’s Cognitive, Affective, and Behavioral Health: Workshop Summary . Washington, DC: The National Academies Press.

Institute of Medicine and National Research Council. (2014c). Building Capacity to Reduce Bullying: Workshop Summary . Washington, DC: The National Academies Press.

Institute of Medicine and National Research Council. (2015). Investing in the Health and Well-Being of Young Adults . Washington, DC: The National Academies Press.

Kim, Y.S., and Leventhal, B. (2008). Bullying and suicide. A review. International Journal of Adolescent Medicine and Health, 20 (2), 133-154.

Koo, H. (2007). A time line of the evolution of school bullying in differing social contexts. Asia Pacific Education Review, 8 (1), 107-116.

Kota, R., Schoohs, S., Benson, M., and Moreno, M.A. (2014). Characterizing cyberbullying among college students: Hacking, dirty laundry, and mocking. Societies, 4 (4), 549-560.

McDougall, P., and Vaillancourt, T. (2015). Long-term adult outcomes of peer victimization in childhood and adolescence: Pathways to adjustment and maladjustment. American Psychologist, 70 (4), 300.

Monks, C.P., and Smith, P.K. (2006). Definitions of bullying: Age differences in understanding of the term and the role of experience. British Journal of Developmental Psychology, 24 (4), 801-821.

National Institute of Justice. (2015). Comprehensive School Safety Initiative. 2015. Available: http://nij.gov/topics/crime/school-crime/Pages/school-safety-initiative.aspx#about [October 2015].

National Research Council and Institute of Medicine. (2002). Community Programs to Promote Youth Development . Committee on Community-Level Programs for Youth. J. Eccles and J.A. Gootman, Editors. Board on Children, Youth, and Families, Division of Behavioral and Social Sciences and Education. Washington, DC: National Academy Press.

National Research Council and Institute of Medicine. (2003). Deadly Lessons: Understanding Lethal School Violence . Case Studies of School Violence Committee. M.H. Moore, C.V. Petrie, A.A. Barga, and B.L. McLaughlin, Editors. Division of Behavioral and Social Sciences and Education. Washington, DC: The National Academies Press.

National Research Council and Institute of Medicine. (2009). Preventing Mental, Emotional, and Behavioral Disorders among Young People: Progress and Possibilities. Committee on the Prevention of Mental Disorders and Substance Abuse Among Children, Youth, and Young Adults: Research Advances and Promising Interventions. M.E. O’Connell, T. Boat, and K.E. Warner, Editors. Board on Children, Youth, and Families, Division of Behavioral and Social Sciences and Education. Washington, DC: The National Academies Press.

Olweus, D. (1978). Aggression in the Schools: Bullies and Whipping Boys. Washington, DC: Hemisphere.

Olweus, D. (1993). Bullying at School. What We Know and Whal We Can Do. Oxford, UK: Blackwell.

Olweus, D. (1996). Bully/victim problems in school. Prospects, 26 (2), 331-359.

Slonje, R., and Smith, P.K. (2008). Cyberbullying: Another main type of bullying? Scandinavian Journal of Psychology, 49 (2), 147-154.

Smith, P. ., and Monks, C. . (2008). Concepts of bullying: Developmental and cultural aspects. International Journal of Adolescent Medicine and Health, 20 (2), 101-112.

Sourander, A. (2010). The association of suicide and bullying in childhood to young adulthood: A review of cross-sectional and longitudinal research findings. Canadian Journal of Psychiatry, 55 (5), 282.

Sticca, F., and Perren, S. (2013). Is cyberbullying worse than traditional bullying? Examining the differential roles of medium, publicity, and anonymity for the perceived severity of bullying. Journal of Youth and Adolescence, 42 (5), 739-750.

Substance Abuse and Mental Health Services Administration. (2015). Safe Schools/Healthy Students. 2015. Available: http://www.samhsa.gov/safe-schools-healthy-students/about [November 2015].

Tanrikulu, I., and Campbell, M. (2015). Correlates of traditional bullying and cyberbullying perpetration among Australian students. Children and Youth Services Review , 55 , 138-146.

Tokunaga, R.S. (2010). Following you home from school: A critical review and synthesis of research on cyberbullying victimization. Computers in Human Behavior, 26 (3), 277-287.

U.S. Department of Education. (2015). Safe and Supportive Schools . Available: http://www.ed.gov/news/press-releases/us-department-education-awards-388-million-safe-and-supportive-school-grants [October 2015].

Vaillancourt, T., Trinh, V., McDougall, P., Duku, E., Cunningham, L., Cunningham, C., Hymel, S., and Short, K. (2010). Optimizing population screening of bullying in school-aged children. Journal of School Violence, 9 (3), 233-250.

van Geel, M., Vedder, P., and Tanilon, J. (2014). Relationship between peer victimization, cyberbullying, and suicide in children and adolescents: A meta-analysis. Journal of the American Medical Association. Pediatrics, 168 (5), 435-442.

Vivolo, A.M., Holt, M.K., and Massetti, G.M. (2011). Individual and contextual factors for bullying and peer victimization: Implications for prevention. Journal of School Violence, 10 (2), 201-212.

Vlachou, M., Andreou, E., Botsoglou, K., and Didaskalou, E. (2011). Bully/victim problems among preschool children: A review of current research evidence. Educational Psychology Review, 23 (3), 329-358.

Wolke, D., and Lereya, S.T. (2015). Long-term effects of bullying. Archives of Disease in Childhood, 100 (9), 879-885.

Ybarra, M.L., Espelage, D.L., and Mitchell, K.J. (2014). Differentiating youth who are bullied from other victims of peer-aggression: The importance of differential power and repetition. Journal of Adolescent Health, 55 (2), 293-300.

This page intentionally left blank.

Bullying has long been tolerated as a rite of passage among children and adolescents. There is an implication that individuals who are bullied must have "asked for" this type of treatment, or deserved it. Sometimes, even the child who is bullied begins to internalize this idea. For many years, there has been a general acceptance and collective shrug when it comes to a child or adolescent with greater social capital or power pushing around a child perceived as subordinate. But bullying is not developmentally appropriate; it should not be considered a normal part of the typical social grouping that occurs throughout a child's life.

Although bullying behavior endures through generations, the milieu is changing. Historically, bulling has occurred at school, the physical setting in which most of childhood is centered and the primary source for peer group formation. In recent years, however, the physical setting is not the only place bullying is occurring. Technology allows for an entirely new type of digital electronic aggression, cyberbullying, which takes place through chat rooms, instant messaging, social media, and other forms of digital electronic communication.

Composition of peer groups, shifting demographics, changing societal norms, and modern technology are contextual factors that must be considered to understand and effectively react to bullying in the United States. Youth are embedded in multiple contexts and each of these contexts interacts with individual characteristics of youth in ways that either exacerbate or attenuate the association between these individual characteristics and bullying perpetration or victimization. Recognizing that bullying behavior is a major public health problem that demands the concerted and coordinated time and attention of parents, educators and school administrators, health care providers, policy makers, families, and others concerned with the care of children, this report evaluates the state of the science on biological and psychosocial consequences of peer victimization and the risk and protective factors that either increase or decrease peer victimization behavior and consequences.

Welcome to OpenBook!

You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

Do you want to take a quick tour of the OpenBook's features?

Show this book's table of contents , where you can jump to any chapter by name.

...or use these buttons to go back to the previous chapter or skip to the next one.

Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

Switch between the Original Pages , where you can read the report as it appeared in print, and Text Pages for the web version, where you can highlight and search the text.

To search the entire text of this book, type in your search term here and press Enter .

Share a link to this book page on your preferred social network or via email.

View our suggested citation for this chapter.

Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

Get Email Updates

Do you enjoy reading reports from the Academies online for free ? Sign up for email notifications and we'll let you know about new publications in your areas of interest when they're released.

U.S. flag

An official website of the United States government

The .gov means it's official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you're on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

  • Publications
  • Account settings
  • Browse Titles

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.

Committee on the Biological and Psychosocial Effects of Peer Victimization: Lessons for Bullying Prevention; Board on Children, Youth, and Families; Committee on Law and Justice; Division of Behavioral and Social Sciences and Education; Health and Medicine Division; National Academies of Sciences, Engineering, and Medicine; Rivara F, Le Menestrel S, editors. Preventing Bullying Through Science, Policy, and Practice. Washington (DC): National Academies Press (US); 2016 Sep 14.

Cover of Preventing Bullying Through Science, Policy, and Practice

Preventing Bullying Through Science, Policy, and Practice.

  • Hardcopy Version at National Academies Press

4 Consequences of Bullying Behavior

Bullying behavior is a serious problem among school-age children and adolescents; it has short- and long-term effects on the individual who is bullied, the individual who bullies, the individual who is bullied and bullies others, and the bystander present during the bullying event. In this chapter, the committee presents the consequences of bullying behavior for children and youth. As referenced in Chapter 1 , bullying can be either direct or indirect, and children and youth may experience different types of bullying. Specifically the committee examines physical (including neurobiological), mental, and behavioral health consequences. The committee also examines consequences for academic performance and achievement and explores evidence for some of the mechanisms proposed for the psychological effects of bullying. When applicable, we note the limited, correlational nature of much of the available research on the consequences of bullying.

  • CONSEQUENCES FOR INDIVIDUALS WHO ARE BULLIED

Mounting evidence on bullying has highlighted the detrimental effects of being bullied on children's health and behavior ( Gini and Pozzoli, 2009 ; Lereya et al., 2015 ; Reijntjes et al., 2010 ; Ttofi et al., 2011 ). In this section, the committee reviews the research on physical, psychosocial, and academic achievement consequences for those children and youth who are bullied.

Perspectives from the Field

Being bullied makes young people incredibly insecure: When you're being bullied, you can feel constantly insecure and on guard. Even if you're not actively being bullied, you're aware it could start anytime. It has a big mental and emotional impact—you feel unaccepted, isolated, angry, and withdrawn. You're always wondering how you can do better and how you can escape a bully's notice. You're also stunted because of the constant tension and because maybe you forego making certain friendships or miss out on taking certain chances that could actually help your development.

—Summary of themes from young adults focus group (See Appendix B for additional highlights from interviews.)

Physical Health Consequences

The physical health consequences of bullying can be immediate, such as physical injury, or they can involve long-term effects, such as headaches, sleep disturbances, or somatization. 1 However, the long-term physical consequences of bullying can be difficult to identify and link with past bullying behavior versus being the result of other causes such as anxiety or other adverse childhood events that can also have physical effects into adulthood ( Hager and Leadbeater, 2016 ). In one of the few longitudinal studies on the physical and mental effects of bullying, Bogart and colleagues (2014) studied 4,297 children and their parents from three urban locales: Birmingham, Alabama; 25 contiguous school districts in Los Angeles County, California; and one of the largest school districts in Houston, Texas. Bogart and her team were interested in the cumulative effects of bullying on an individual. They collected data when the cohort was in fifth grade (2004 to 2006), seventh grade (2006 to 2008), and tenth grade (2008 to 2010). Data consisted of responses to the Peer Experience Questionnaire, the Pediatric Quality of Life Inventory with its Psychosocial Subscale and Physical Health Subscale, and a Self-Perception Profile. The Physical Health Subscale measured perceptions of physical quality of life.

Bogart and colleagues (2014) found that children who were bullied experienced negative physical health compared to non-involved peers. Among seventh grade students with the worst-decile physical health, 6.4 percent were not bullied, 14.8 percent had been bullied in the past only, 23.9 percent had been bullied in the present only, and nearly a third (30.2%) had been bullied in both the past and present. These effects were not as strong when students were in tenth grade. Limitations to this study were that physical health was measured by participants' perceptions of their health-related quality of life, rather than by objectively defined physical symptoms. It is critical to understand that this study, or other studies assessing correlations between behavior and events, cannot state that the events caused the behavior. Future research might build on this large multisite longitudinal study and obtain more in-depth evidence on individuals' physical health as a consequence of bullying.

In their study of 2,232 twins reared together and separately as a part of the Environmental Risk (E-Risk) Longitudinal Twin Study, Baldwin and colleagues (2015) found that children who had experienced chronic bullying showed greater adiposity subsequently, but not at the time of victimization. The study revealed that at age 18, these children had a higher body mass index ( b = 1.11, CI [0.33, 1.88]), waist-hip ratio ( b = 0.017, CI [0.008, 0.026]), and were at a higher risk of being overweight ( OR = 1.80, CI [1.28, 2.53]) than their nonbullied counterparts ( Baldwin et al., 2015 ).

An important future direction for research is to gather more information on physical consequences such as elevated blood pressure, inflammatory markers, and obesity in light of work showing effects on these outcome of harsh language by parents and other types of early life adversity ( Danese and Tan, 2014 ; Danese et al., 2007 ; Evans et al., 2007 ; Miller and Chen, 2010 ).

Somatic Symptoms

Most of the extant evidence on the physical consequences—somatic symptoms in particular—of bullying pertains to the individual who is bullied. The emotional effects of being bullied can be expressed through somatic disturbances, which, similar to somatization, are physical symptoms that originate from stress or an emotional condition. Common stress or anxiety-related symptoms include sleep disorders, gastrointestinal concerns, headaches, palpitations, and chronic pain. The relationship between peer victimization and sleep disturbances has been well documented ( Hunter et al., 2014 ; van Geel et al., 2014 ).

For instance, Hunter and colleagues (2014) examined sleep difficulties (feeling too tired to do things, had trouble getting to sleep, and had trouble staying asleep) among a sample of 5,420 Scottish adolescents. The researchers found that youth who were bullied ( OR = 1.72, 95% CI [1.07, 2.75]) and youth who bully ( OR = 1.80, CI [1.16, 2.81]) were nearly twice as likely as youth who were not involved in bullying to experience sleep difficulties. One limitation of this study is that it was based on self-reports, which have sometimes been criticized as being subject to specific biases. Patients with insomnia may overestimate how long it takes them to fall asleep ( Harvey and Tang, 2012 ). Another limitation is that the study included young people at different stages of adolescence. Sleep patterns and sleep requirements vary across the different stages of adolescence.

A recent meta-analysis based on 21 studies involving an international sample of 363,539 children and adolescents examined the association between peer victimization and sleeping problems. A broader focus on peer victimization was used because of the definitional issues related to bullying. The authors defined peer victimization as “being the victim of relational, verbal or physical aggression by peers” ( van Geel et al., 2015 , p. 89). Children and youth who were victimized reported more sleeping problems than children who did not report victimization ( OR = 2.21, 95% CI [2.01, 2.44]). Moreover, the relationship between peer victimization and sleeping problems was stronger for younger children than it was for older children ( van Geel et al., 2015 ). This study was based on cross-sectional studies that varied widely in how peer victimization and sleeping problems were operationalized and thus cannot make any claims about causal relations between peer victimization and sleeping problems.

Knack and colleagues (2011a) posited that bullying results in meaningful biological alterations that may result in changes in one's sensitivity to pain responses. A recent meta-analysis by Gini and Pozzoli (2013) concluded that children and adolescents who are bullied were at least twice as likely to have psychosomatic disturbances (headache, stomachache, dizziness, bedwetting, etc.) than nonbullied children and adolescents ( OR = 2.39, 95% CI [1.76, 3.24] for longitudinal studies; OR = 2.17, 95% CI [1.91, 2.46] for cross-sectional studies). Although the use of self-report measures are very common in bullying research and are usually considered to be valid and reliable (Ladd and Kochenderfer- Ladd, 2002 ), their use requires adequate self-awareness on the part of the respondent, and some children who are bullied may be in denial about their experience of having been bullied.

There is also evidence of gender differences in the physical effects of being bullied. For example, Kowalski and Limber (2013) examined the relation between experiences with cyberbullying or traditional bullying (i.e., bullying that does not involve digital electronic means of communication) and psychological and physical health, as well as academic performance, of 931 students in grades 6 through 12 living in rural Pennsylvania. Students were asked how often in the past 4 weeks they experienced 10 physical health symptoms, with scores across these 10 symptoms averaged to provide an overall health index (higher scores equal more health problems). Traditional bullying was defined as “aggressive acts that are meant to hurt another person, that happen repeatedly, and that involve an imbalance of power” ( Kowalski and Limber, 2013 , p. S15). The authors found that girls who were traditionally bullied reported more anxiety and overall health problems than boys who were bullied (females: M = 1.65, SD = 0.41; males: M = 1.42, SD = 0.38). A limitation of this study is that it is correlational in nature and the authors cannot conclude that being a victim of traditional bullying caused the psychological or physical problems.

In summary, it is clear that children and youth who have been bullied also experience a range of somatic disturbances. There are also gender differences in the physical health consequences of being bullied.

Neuroendocrinology of Stress

Psychological and physical stressors, such as being the target of bullying, activate the stress system centered on the hypothalamic-pituitary-adrenal (HPA) axis ( Dallman et al., 2003 ; McEwen and McEwen, 2015 ). The role of HPA and other hormones is to promote adaptation and survival, but chronically elevated hormones can also cause problems. Stress has ubiquitous effects on physiology and the brain, alters levels of many hormones and other biomarkers, and ultimately affects behavior. Therefore, both a general understanding of stress during early adolescence and, where known, specific links between stress and bullying can provide insight into the enduring effects of bullying.

The levels of the stress hormone cortisol have been shown to change in targets of repeated bullying, with being bullied associated with a blunted cortisol response ( Booth et al., 2008 ; Kliewer, 2006 ; Knack et al., 2011b ; Ouellet-Morin et al., 2011 ; Vaillancourt et al., 2008 ). To the committee's knowledge, no study has examined bidirectional changes in cortisol, although there is evidence to suggest that cortisol is typically elevated immediately following many types of stress and trauma but blunted after prolonged stress ( Judd et al., 2014 ; Miller et al., 2007 ). Kliewer (2006) did find that cortisol increased from pre-task to post-task (i.e., watching a video clip from the film Boyz 'n the Hood followed by a discussion) among youth who had been bullied, and in a more recent study, Kliewer and colleagues (2012) reported, among African American urban adolescents, that peer victimization was associated with greater sympathetic nervous system (fight or flight reaction) reactivity to a stress task (measured using salivary a-amylase, an enzyme that increases in saliva when the sympathetic nervous system is activated). However, in these studies, the immediate effect of being bullied on stress reactivity was not examined. In contrast, Ouellet-Morin and colleagues (2011) and Knack and colleagues (2011b) did not find an increase in cortisol in bullied youth following a psychosocial stress test but rather found a blunted pattern of response after the test had concluded (see Figures 4-1 and 4-2 ). In order to test whether, in the short-term, bullying produces an increase in cortisol, whereas in the long-term it is associated with a blunted cortisol response (as seen with other types of psychosocial stressors; Judd et al., 2014 ; Miller et al., 2007 ), a longitudinal study is needed to examine bullying chronicity and regulation of the HPA axis. The importance of this future work notwithstanding, there is evidence to support a finding that when stress becomes prolonged, the stress hormone system becomes hypofunctional and a blunted stress response results ( McEwen, 2014 ).

Cortisol reactivity for victimized and nonvictimized adolescents during the Trier Social Stress Test. SOURCE: Adapted from Knack et al. (2011b, Fig. 3, p. 5).

Cortisol responses to a psychosocial stress test (PST) in the total sample and according to maltreatment/bullying victimization. SOURCE: Adapted from Ovellet-Morin et al. (2011, Fig. 1, p. 14).

When stress becomes prolonged, the stress hormone system becomes hypofunctional and a blunted stress response results ( Knack et al., 2012a ; McEwen, 2014 ; Vaillancourt et al., 2013a ). That is, the elevation in cortisol in response to stress fails to occur. Scientists are not exactly sure how this happens, but evidence suggests that the stress system has shut itself down through “negative feedback.” Although on the surface this may seem to be beneficial, it is not. Cortisol has many functions and serves to regulate myriad biological systems; a blunted stress response compromises the orchestration of cortisol's biological functions. The critical importance of the massive over-activation of the stress system producing a blunted stress response is clinically relevant since it is associated with posttraumatic stress disorder and other psychiatric disorders ( Heim et al., 1997 ). It is also relevant for understanding an individual's inability to self-regulate and cope with stress.

Prolonged stress also disrupts the circadian or daily rhythm of cortisol, which is normally elevated in the morning and slowly decreases over the day to result in low levels at bedtime ( Barra et al., 2015 ). An altered circadian rhythm results not only in difficulty awaking in the morning but also in difficulty falling asleep at night. It can cause profound disruption in sleep patterns that can initiate myriad additional problems; sleep deficits are associated with problems with emotional regulation, learning, mood disorders, and a heightened social threat detection and response system ( McEwen and Karatsoreos, 2015 ). Recent research suggests that the consolidation of memories 2 one learns each day continues during sleep ( Barnes and Wilson, 2014 ; Shen et al., 1998 ). Sleep disturbances disrupt memory consolidation, and studies in animals suggest stress during learning engages unique neurochemical and molecular events that cause memory to be encoded by some unique mechanism ( Baratta et al., 2015 ; Belujon and Grace, 2015 ; McGaugh, 2015 ; Rau and Fanselow, 2009 ). Although victims of bullying have sleep problems ( Miller-Graff et al., 2015 ), causal relations between bullying, sleep disorders, learning/memory consolidation, and cortisol dysregulation have not been established. Indeed, these correlations between being a target of bullying and physiological problems may highlight important interactions between events and outcome, but it is also likely that unidentified variables might be the critical causal factors.

It is also noteworthy that the HPA axis showed heightened responsiveness during the peak ages of bullying ( Blakemore, 2012 ; Dahl and Gunnar, 2009 ; Romeo, 2010 ; Spear, 2010 ). For example, cortisol response characteristics in children are such that, when cortisol is activated, the hormonal response is protracted and takes almost twice as much time to leave the blood and brain compared to adults ( Romeo, 2010 , 2015 ). The circadian rhythm of cortisol also seems altered during early adolescence, most notably associated with morning cortisol levels, with levels increasing with age and pubertal development ( Barra et al., 2015 ). Animal models suggest that the extended cortisol response begins in pre-puberty and indicate that recovery from stressful events is more challenging during this age range ( Romeo, 2015 ).

Emotional regulation, including a person's ability to recover from a traumatic or stressful event, involves being able to regulate or normalize stress hormone levels. Before adolescence, children's ability to regulate their stress response can be greatly assisted by parents or other significant caregivers—a process referred to as “social buffering” ( Hostinar et al., 2014 ; Ouellet-Morin et al., 2011 , 2013 ). Specifically, it is well documented in the human and animal research literature that a sensitive caregiver or a strong support system can greatly dampen the stress system's response and actually reduce the amount of stress hormone released, as well as shorten the amount of time the stress hormones circulate within the body and brain. This results in dramatic decreases in stress-related behavior ( Gee et al., 2014 ; Hostinar et al., 2014 ). The social cues actually reduce stress by reducing the activation of the stress system, or HPA axis, at the level of the hypothalamus ( Hennessy et al., 2009 , 2015 ; Moriceau and Sullivan, 2006 ). The social stimuli that buffer children as they transition into adolescence appear to begin to have greater reliance on peers rather than on the caregiver ( Hostinar et al., 2015 ).

Other physiological effects of stress include the activation of the immune system by bullying-induced stress ( Copeland et al., 2014 ; McCormick and Mathews, 2007 ), and a cardiovascular blunting among individuals with a history of being bullied ( Newman, 2014 ). Other hormones and physiological mechanisms are also involved in the stress activation response. For example, cortisol is associated with an increase in testosterone, the male sex hormone associated with aggression in nonhuman animals and with dominance and social challenge in humans, particularly among boys and men ( Archer, 2004 ). In fact, in rodents the combined assessment of testosterone and cortisol provides more predictive value of behavioral variability ( McCormick and Mathews, 2007 ) compared to controls ( Márquez et al., 2013 ). In humans, there is increasing evidence supporting an interaction between testosterone and cortisol in the prediction of social aggression (see Montoya et al., 2012 ). In a study of 12-year-olds, Vaillancourt and colleagues (2009) found that testosterone levels were higher among bullied boys than nonbullied boys, but lower among bullied girls than nonbullied girls. The authors speculated that the androgen dynamics were possibly adrenocortical in origin, highlighting the need to examine testosterone and cortisol in consort. To date, researchers have only investigated cortisol response to being bullied ( Kliewer, 2006 ; Knack et al., 2011b ; Ouellet-Morin et al., 2011 ; Vaillancourt et al., 2008 ), and only one study has examined testosterone and peer victimization ( Vaillancourt et al., 2009 ). There are no studies examining these two important hormones together in relation to bullying perpetration or to being bullied.

Together, the research on both humans and animals suggests that stress is beneficial when it is experienced at low-to-moderate levels, whereas prolonged or repeated stress becomes toxic by engaging a unique neural and molecular cascade within the brain that is thought to initiate a different developmental pathway. Indeed, from animal models, brain architecture is altered by chronic stress, with amygdala activity being enhanced, hippocampal function impaired, and medial prefrontal cortex function being reduced, leading to increased anxiety and aggression and decreased capacity for self-regulation, as well as a more labile mood ( Chattarji et al., 2015 ; McEwen and Morrison, 2013 ; McEwen et al., 2015 ). This stress effect on the brain is particularly strong when experienced during adolescence, but it is even more pronounced if combined with early life adversity ( Gee et al., 2014 ; Hanson et al., 2015 ; Richter-Levin et al., 2015 ; Romeo, 2015 ; Sandi and Haller 2015 ). This could produce behavioral responses that become maladaptive by compromising emotional and cognitive functioning or perhaps it could produce adaptive behavior for a dangerous environment that results in socially inappropriate behavior.

Consequences of Bullying on Brain Function

Being a child or youth who is bullied changes behavior, and neuroscience research suggests this experience may also change the brain ( Bradshaw et al., 2012 ; Vaillancourt et al., 2013a ). The major technique used to monitor brain function in humans is functional magnetic resonance imaging (fMRI), which works by monitoring blood flow to indirectly assess the functioning of thousands of brain cells over an area of the brain. This technique has rarely been used on either the perpetrator or target of a bullying incident during this very particular social interaction, and for that reason little is known about whether or not the brain of a child who bullies or of a child who has been bullied is different before these experiences or is changed by them. These very specific studies are required before one can make definitive statements about the brain for this topic or for how this information might help develop novel interventions or prevention.

Additionally, it is important to consider two limitations for understanding fMRI. First, one cannot scan the brain of a child during the action of bullying or being a target of bullying. Instead, one must rely on the child staying perfectly still as the investigator tries to approximate one or two aspects of the complex experience that occur in this complicated behavioral interaction. For example, the fMRI task used during a brain imaging session might mimic social exclusion as one facet of bullying, without the full social and emotional context of the real bullying process. Although this is an important methodology, these results need to be assessed with caution at this time and not directly applied as an accepted scientific interpretation of bullying. Therefore, the examples used below to assess brain function rely not on monitoring actual instances of bullying behavior but on monitoring components of behaviors that are thought to occur during a bullying incident.

Second, fMRI monitors a large brain area, which is composed of many smaller brain areas, each of which is involved in many, many behaviors, many of which are not yet fully understood. Thus, it is difficult to determine why the brain area one is examining changed, since that brain area is involved in hundreds of diverse behaviors. For this reason, the results reviewed below need to be viewed as preliminary and should not be misinterpreted as explaining any aspect of the experience of bullying. Rather, these preliminary results highlight the importance of brain assessment before and after bullying experiences, including developing monitorable tasks that more closely approximate the bullying experience within the physical constraints of an immobile subject during an fMRI brain scan. The value of neuroscience is that it enables exploration of brain mechanisms controlling behavior that are not obvious from behavioral assessment.

Social Pain

Whereas there are no studies directly examining bullying using neural imaging techniques, there are several studies examining how the brain processes social pain. Social pain describes the “feelings of pain that follow the experiences of peer rejection, ostracism, or loss” ( Vaillancourt et al., 2013a , p. 242). Social pain is consistent with how people describe their feeling about being bullied. For example, one victim of bullying described the emotional toll of his experience by saying, “I feel like, emotionally, they [his bullies] have been beating me with a stick for 42 years” ( Vaillancourt et al., 2013a , p. 242).

Researchers have demonstrated that when people experience social pain, they activate regions in their brain similar to those activated when they experience physical pain ( Eisenberger, 2012 ; Eisenberger and Lieberman, 2004 ; Eisenberger et al., 2003 ; Kross et al., 2011 ; Vaillancourt et al., 2010a ). Specifically, the dorsal anterior cingulate cortex, which is part of the prefrontal cortex, seems to be implicated in the processing of both physical and social pain. The fact that physical and social pain have overlapping neural systems might explain why people tend to use physical pain metaphors (e.g., “It broke my heart when she called me ugly.”) when describing their experiences with being humiliated, oppressed, or rejected ( Eisenberger, 2012 ). Eisenberger and Leiberman (2004) noted that these fMRI results are correlations between pain and the anterior cingulate cortex and could reflect other functions of that brain region, such as detecting conflict or errors, different ideas or goals about the task, or individual differences in the task difficulty. In a recent fMRI study by Rudolph and colleagues (2016) , adolescent girls were socially excluded during a laboratory task (i.e., cyberball; Williams et al., 2000 ). Results indicated that activation of the social pain network—the dorsal anterior cingulate cortex, subgenual anterior cingulate cortex, and anterior insula—was associated with internalizing symptoms. Of note, this effect was particularly pronounced among adolescent girls with a history of peer victimization. 3

In addition to studies on social pain, there are some studies examining how the brains of children who had been bullied reacted subsequently to different stimuli. Experiences of being bullied can alter an individual's view of the world. While no brain imaging study has directly addressed this issue, a longitudinal study investigating the risk factors of depression found that being a child who was bullied at ages 11 and 12 was associated with a decreased response to reward in the medial prefrontal cortex at age 16, although it was unclear if these brain differences were present before the bullying experiences or developed after them ( Casement et al., 2014 ). The medial prefrontal cortex, which is a brain area involved in memory and learning, was found to be disrupted in children who have been bullied ( Vaillancourt et al., 2011 ). Because it also has countless other functions including decision making, risk taking, and conflict monitoring, disruption of this region compromises one's ability to interpret results with respect to bullying ( Euston et al., 2012 ; Vaillancourt et al., 2011 ).

In another fMRI study involving children, 10-12 years old, who were presented with a task that examined their response to negative feedback stimuli of emotional faces, greater and more extensive brain activation was found in the amygdala, orbitofrontal cortex, and ventrolateral prefrontal cortex of children who had been rejected by their peers, compared with children in a control group who had not been rejected by peers ( Lee et al., 2014 ), a condition that is highly correlated with being bullied by peers ( r = .57; Knack et al., 2012a ). The prefrontal cortex is a very large brain area with many subareas, all of which serve diverse functions in many different behaviors, not just executive function. Indeed, the prefrontal cortex processes pain, self-regulation, stress integration, and safety signals and has been implicated in psychiatric disorders, higher order learning, extinction (active process to suppress a memory), personality, social behavior, planning, decision making, and many other behaviors and percepts including social exclusion, social/physical pain, and empathy ( Casey and Jones, 2010 ; Spear, 2013 ). These few studies are consistent with other imaging studies demonstrating functional brain differences among individuals who were maltreated in childhood ( Lim et al., 2014 , 2015 ). Taken together, this work supports a finding that being exposed to such adversity during maturation has enduring effects on brain function, although additional research is needed to establish the parameters controlling these effects (and qualifying the generalization).

There is also evidence that stressful events, such as might occur with bullying experiences, impact emotional brain circuits, an inference that is supported by changes in amygdala architecture and function described earlier in animal models in adulthood but more robust changes in brain structure are produced by stress during early life and around adolescence ( Chattarji et al., 2015 ; McEwen and Morrison, 2013 ; McEwen et al., 2015 ). This point is critical because the stress system of adolescents seems to have a heightened sensitivity, and experiencing bullying can increase stress hormones ( Romeo, 2010 , 2015 ; Spear, 2013 ; Vaillancourt et al., 2011 ). Human brain scanning experiments suggest the prefrontal cortex is affected by stress through attenuating the connectivity to the hippocampus and amygdala, which are brain areas critical for emotional regulation and emotional memories ( Ganzel et al., 2008 ; Liston et al., 2009 ). Animal research shows that this connectivity loss is caused by stress-induced atrophy of the prefrontal cortex ( Radley et al., 2006 ), although this brain region does show the ability to recover once the stress has terminated ( Liston et al., 2009 ). One aspect of being a target of bullying is that the memory of the experience seems to be enduring; the unique function of the prefrontal cortex and emotional circuits during preadolescence and adolescence may provide insight into the enduring memories of being bullied. Specifically, one function of the prefrontal cortex is to help suppress memories that are no longer important or true. Typically, memories are not simply forgotten or unlearned. Rather, as we update information in our brain, the old memory is suppressed by overlaying a new memory to attenuate the old memory, an active brain process called extinction ( Milaid and Quirk, 2012 ). With respect to memories of trauma, of being bullied, or of experiencing a threat, the prefrontal cortex is important for attenuating (extinguishing) memories in emotional brain areas, such as the amygdala. Importantly, dramatic changes occur in the extinction system during adolescence, where fear extinction learning is attenuated relative to children and adults ( Pattwell et al., 2012 , 2013 ). This learning mode has been modeled in animals to understand how the process occurs in the adolescent brain ( Kim and Richardson, 2010 ; Nair and Gonzalez-Lima, 1999 ; Pattwell et al., 2012 ). The research suggests that around the time of adolescence, it is more difficult to decrease emotionally aversive memories, such as experiences of being bullied, than at other times in the life cycle. Furthermore, anxious teens (anxiety is sometimes comorbid with experience of being bullied) show even greater difficulties with processing extinction of fear memory ( Jovanovic et al., 2013 ).

In conclusion, the available evidence indicates that the brain functioning of individuals who are bullied is altered (see reviews by Bradshaw et al., 2012 ; Vaillancourt et al., 2013a ). However, it is difficult to ascertain fully what it means when fMRI scans detect an alteration in brain activity. In terms of understanding the prolonged and repeated stress associated with bullying, this research suggests that greater experience with being bullied and repeated exposure as a target of bullying produces a neural signature in the brain that could underlie some of the behavioral outcomes associated with being bullied.

Psychosocial Consequences

In this section, the committee examines what is known about the psychosocial consequences of being bullied. A common method of examining mental health issues separates internalizing and externalizing problems ( Sigurdson et al., 2015 ). Internalizing symptoms include problems directed within the individual, such as depression, anxiety, fear, and withdrawal from social contacts. Externalizing symptoms reflect behavior that is typically directed outwards toward others, such as anger, aggression, and conduct problems, including a tendency to engage in risky and impulsive behavior, as well as criminal behavior. Externalizing problems also include the use and abuse of substances.

Psychological problems are common after being bullied (see review by Hawker and Boulton, 2000 ) and include internalizing problems, such as depression, anxiety, and, especially for girls, self-harming behavior ( Kidger et al., 2015 ; Klomek et al., 2009 , 2015 ). There can also be subsequent externalizing problems, especially for boys (see review by McDougall and Vaillancourt, 2015 ). Rueger and colleagues (2011) found consistent concurrent association with timing of peer victimization and maladjustment. Both psychological and academic outcomes were particularly strong for students who experienced sustained victimization over the school year.

“And these are the kids that are at risk for anxiety and depression and bipolar disorder to begin with, and it almost seems like it's a cycle that makes it worse. So they are isolated and they are angry, they are fearful. Many of them end up severely depressed, attempting suicide, utilizing NSSIs [nonsuicidal self-injuries] for comfort. Some turn to gangs because that is the group that would accept them. So that's when we get involved and we have to start working backwards.”

—Quote from community-based provider discussing bullying during focus group (See Appendix B for additional highlights from interviews.)

Internalizing Problems

A robust literature documents that youth who are bullied often have low self-esteem and feel depressed, anxious, and lonely ( Juvonen and Graham, 2014 ). Data from developmental psychopathology research indicate that stressful life events can lead to the onset and maintenance of depression, anxiety, and other psychiatric symptoms and that for many youth, being bullied is a major life stressor ( Swearer and Hymel, 2015 ). Based on sociometric nominations, targets of bullying also are disliked by the general peer group ( Knack et al., 2012b ).

Several meta-analyses have specifically explored the relation between depression and being bullied at school ( Ttofi et al., 2011 ) and victimized by peers 4 ( Hawker and Boulton, 2000 ; Reijntjes et al., 2010 ). Individuals who had been cyberbullied reported higher levels of depression and suicidal ideation, as well as increased emotional distress, externalized hostility, and delinquency, compared with peers who were not bullied ( Patchin, 2006 ; Ybarra et al., 2006 ). Furthermore, severity of depression in youth who have been cyberbullied has been shown to correlate with the degree and severity of cyberbullying ( Didden et al., 2009 ).

Two meta-analyses found that across several different longitudinal studies using different study populations, internalizing emotional problems increases both the risk and the harmful consequences of being bullied ( Cook et al., 2010 ; Reijntjes et al., 2010 ). Internalizing problems can thus function as both antecedents and consequences of bullying ( Reijntjes et al., 2010 ; Vaillancourt et al., 2013b ). Although most longitudinal studies suggest that psychological problems result from being bullied (see review by McDougall and Vaillancourt, 2015 ) and meta-analyses ( Reijntjes et al., 2010 ; Ttofi et al., 2011 ) support this directionality, there is some evidence that for some youth, the temporal pattern begins with mental health problems ( Kochel et al., 2012 ; Vaillancourt et al., 2013b ).

In a large cohort of Canadian children followed every year from grade 5 to grade 8, Vaillancourt and colleagues (2013b) found that internalizing problems in grades 5 and 7 predicted increased self-reported bullying behavior the following year. They noted that these findings provide evidence for the “symptom-driven pathway” across time with increased internalizing problems predicting greater self-reported peer victimization. This “symptom-drive pathway” was noted from grade 5 to grade 6 and again from grade 7 to grade 8 and was consistent with other published work. For instance, Kochel et al. (2012) reported a symptom-driven pathway in which depressive symptoms predicted peer victimization 5 1 year later (grade 4 to grade 5 and grade 5 to grade 6) and argued that this pathway may result from depressed youth displaying “social deficits,” selecting “maladaptive relationships,” and/or displaying a behavioral style that is perceived poorly by the peer group ( Kochel et al., 2012 , p. 638). Vaillancourt and colleagues (2013b) have also argued that depressed youth could be more “treat sensitive.” That is, these youth may select information from their environment that is consistent with their negative self-opinion. The idea that certain individuals may be more sensitive to environmental cues or make more hostile interpretation of ambiguous social data has been well documented in the literature ( Crick and Dodge, 1994 ; Dodge, 1986 ). This work is consistent with studies showing that social information processing differs in children based on their experience with being bullied and that hypersensitivity can impact their interpretation of social behavior and their self-reports of subsequent incidents of being bullied ( Camodeca et al., 2003 ; Smalley and Banerjee, 2013 ).

Most longitudinal studies to date are of relatively short duration (i.e., less than 2 years) and focus on a narrow developmental period such as childhood or adolescence ( McDougall and Vaillancourt, 2015 ). Nevertheless, there are several recently published studies examining the long-term adult outcomes of childhood bullying. These studies indicate that being bullied does affect future mental health functioning, as reviewed in the following paragraphs.

Most long-term studies of childhood bullying have focused on links to internalizing problems in adulthood, demonstrating robust long-standing effects ( Gibb et al., 2011 ; Olweus, 1993b ; Sourander et al., 2007 ; Stapinski et al., 2014 ). For example, Bowes and colleagues (2015) examined depression in a large sample of participants who reported being the target of bullying at age 13 and found higher rates of depression at age 18 compared to peers who had not been bullied. Specifically, they reported that 14.8 percent of participants who reported being frequently bullied in childhood at age 13 were clinically depressed at age 18 ( OR = 2.96, 95% CI [2.21, 3.97]) and that the population attributable fraction was 29.2 percent, suggesting that close to a third of the variance in depression could be explained by being bullied in childhood ( Bowes et al., 2015 ).

In another longitudinal study using two large population-based cohorts from the United Kingdom (the ALSPAC Cohort) and the United States (the GSMS Cohort), Lereya and colleagues (2015) reported that the effects of childhood bullying on adult mental health were stronger in magnitude than the effects of being maltreated by a caregiver in childhood. Being bullied only (and not maltreated) placed individuals at higher risk for mental health difficulties than being maltreated only (and not bullied) ( OR = 1.6, 95% CI [1.1, 2.2] for ALSPAC cohort; OR = 3.8, 95% CI [1.8, 7.9] for GSMS cohort). Children who were bullied were more likely than maltreated children to be anxious ( OR = 4.9, 95% CI [2.0, 12.0] for GSMS cohort), depressed ( OR = 1.7, 95% CI [1.1, 2.7] for ALSPAC cohort), and to engage in self-harming behavior ( OR = 1.7, 95% CI [1.1-2.6] for ALSPAC cohort) in adulthood ( Lereya et al., 2015 ).

Similarly, Stapinski and colleagues (2014) found that adolescents who experienced frequent peer victimization 6 were two to three times more likely to develop an anxiety disorder 5 years later at age 18 than nonvictimized adolescents ( OR = 2.49, 95% CI [1.62, 3.85]). The association remained after adjusting for potentially confounding individual and family factors and was not attributable to diagnostic overlap with depression. Frequently victimized adolescents were also more likely to develop multiple internalizing problems in adulthood ( Stapinski et al., 2014 ). After controlling for childhood psychiatric problems or family hardship, Copeland and colleagues (2013) found that individuals who were bullied continued to have higher prevalence of generalized anxiety ( OR = 2.7, 95% CI [1.1, 6.3]).

These findings suggest that being bullied and internalizing problems such as depression are mutually reinforcing, with the experience of one increasing the risk of the other in a harmful cycle that contributes to the high stability of being both bullied and experiencing other internalizing problems. These studies also suggest that the long-term consequences of being bullied, which extend into adulthood, can be more severe than being maltreated as a child by a caregiver.

Externalizing Problems

Alcohol and drug abuse and dependence have been associated with being bullied as a child ( Radliff et al., 2012 ). A longitudinal study of adolescents found that those who reported being bullied were more likely to report use of alcohol, cigarettes, and inhalants 12 months later ( Tharp-Taylor et al., 2009 ), compared to those who did not report being bullied. More longitudinal research that tracks children through adulthood is needed to fully understand the link between being bullied and substance abuse (see review by McDougall and Vaillancourt, 2015 ).

Several studies show links between being bullied and violence or crime, especially for men ( Gibb et al., 2011 ; McGee et al., 2011 ; Sourander et al., 2007 , 2011 ). A meta-analysis by Reijntjes and colleagues (2011) that included studies with data on 5,825 participants showed that after controlling for externalizing symptoms at baseline, peer victimization—under which they included being the target of teasing, deliberate exclusion, and being the target of physical threats and malicious gossip—was associated over time with exhibiting externalizing problems such as aggression, truancy, and delinquency ( r = .14, 95% CI [.09, .19]). This research team also found that externalizing problems predicted changes in peer victimization over time ( r = .13, 95% CI [.04, .21]) and concluded that there is a bidirectional relationship between peer victimization and externalizing problems.

Psychotic Symptoms

Evidence from the broader research on childhood trauma and stress indicates that earlier adverse life experiences, such as child abuse, are associated with the development of psychotic symptoms later in life ( Institute of Medicine and National Research Council, 2014b ). Until recently, the association between bullying and psychotic symptoms has been understudied ( van Dam et al., 2012 ). Two recent meta-analyses support the association between bullying and the development of psychotic symptoms later in life ( Cunningham et al., 2015 ; van Dam et al., 2012 ). van Dam and colleagues (2012) conducted a meta-analysis of 14 studies to assess whether being bullied in childhood is related to the development of psychotic (either clinical or nonclinical) symptoms. (Nonclinical psychotic symptoms 7 place individuals at risk for the development of psychotic disorders ( Cougnard et al., 2007 ).) Results from the analyses of studies that examined the association between bullying and nonclinical symptoms (six studies) were more definitive (adjusted OR = 2.3; 95% CI [1.5, 3.4]), with stronger associations when there was an increased frequency, severity, and persistence of bullying ( Cougnard et al., 2007 ). Although some research has found this association, a recent longitudinal study from New Zealand found that the link between bullying and the development of psychosis later in life is likely not causal but instead reflects the fact that individuals who display disordered behaviors across childhood and adolescences are more likely to become bullying targets ( Boden et al., 2016 ) An analysis of studies that examined the association between bullying and psychosis in clinical samples was inconclusive ( van Dam et al., 2012 ).

A recent meta-analysis conducted by Cunningham and colleagues (2015) examined ten European prospective studies, four from the Avon Longitudinal Study of Parents and Children. This analysis found that individuals who were bullied were more than twice as likely to develop later psychotic symptoms, compared to those who were not bullied ( OR = 2.1, 95% CI [1.1, 4.0]). These results were consistent in all but one of the studies included in the meta-analysis. More longitudinal research is needed to more fully understand the mechanisms through which trauma such as bullying may lead to the development of psychotic symptoms ( Cunningham et al., 2015 ; van Dam et al., 2012 ). Importantly, this research will need to be prospective and examine the development of bullying and psychotic symptoms in order to truly identify the temporal priority. The inclusion criteria for the Cunningham and colleagues (2015) meta-analysis included that the study had to be prospective and had to include a measure of psychosis and that bullying needed to be reported before the age of 18. Although the authors stated that “bullying appears to cause later development of psychosis,” such a conclusion requires that mental health functioning be assessed early and over time, as it is possible that premorbid characteristics may make individuals targets for poor peer treatment (see Kochel et al., 2012 ; Vaillancourt et al., 2013b , regarding depression leading to peer victimization).

Academic Performance Consequences

A growing literature has documented that targets of bullying suffer diminished academic achievement whether measured by grades or standardized test scores ( Espelage et al., 2013 ; Nakamoto and Schwartz, 2010 ). Cross-sectional research indicates that children who are bullied are at increased risk for poor academic achievement ( Beran, 2009 ; Beran and Lupart, 2009 ; Beran et al., 2008 ; Glew et al., 2005 ; Neary and Joseph, 1994 ; see also meta-analysis by Nakamoto and Schwartz, 2010 ) and increased absenteeism ( Juvonen et al., 2000 ; Kochenderfer and Ladd, 1996 ; Vaillancourt et al., 2013b ).

The negative relation between being bullied and academic achievement is evident as early as kindergarten ( Kochenderfer and Ladd, 1996 ) and continues into high school ( Espinoza et al., 2013 ; Glew et al., 2008 ). In a 2-week daily diary study with ninth and tenth grade Latino students, Espinoza and colleagues (2013) reported that on days when adolescents' reports of being bullied were greater than what was typical for them, they also reported more academic challenges such as doing poorly on a quiz, test, or homework and felt like less of a good student. Thus, even episodic encounters of being bullied can interfere with a student's ability to concentrate on any given day. In a cross-sectional study of more than 5,000 students in grades 7, 9, and 11, Glew and colleagues (2008) found that for every 1-point increase in grade point average (GPA), the odds of being a child who was bullied (versus a bystander) decreased by 10 percent. However, due to the cross-sectional nature of this study, this association does not establish whether lower academic achievement among children who were bullied was a consequence of having been bullied.

Several short-term (one academic year) longitudinal studies indicate that being bullied predicts academic problems rather than academic problems predicting being a target of bullying ( Kochenderfer and Ladd, 1996 ; Schwartz et al., 2005 ). Given the impairments in brain architecture associated with self-regulation and memory in animal models and the currently limited imaging data in human subjects, this is a reasonable inference, although reverse causation is possible. For instance, early life abuse and neglect impair these same abilities, lower self-esteem, and may make an individual more likely to be a target of bullying. In one of the few longitudinal studies to extend beyond one year, Juvonen and colleagues (2011) examined the relation between victimization 8 and academic achievement across the three years of middle school. Academic adjustment was measured by both year-end grades and teacher reports of engagement. These authors found that more self-reported victimization was related to lower school achievement from sixth to eighth grade. For every 1-unit increase in victimization (on a 1-4 scale), GPA declined by 0.3 points.

Other short-term longitudinal studies found similar results. For example, Nansel and colleagues (2003) found that being bullied in a given year (grade 6 or 7) predicted poor academic outcomes the following year, after controlling for prior school adjustment and if they were previously targets of bullying or not. Similarly, Schwartz and colleagues (2005) reported a negative association for third and fourth grade children between victimization 9 and achievement 1 year later. In addition, Baly and colleagues (2014) found that the cumulative impact of being bullied over 3 years from sixth grade to eighth grade had a negative impact on GPA and standardized test scores.

However, other studies have not found such associations. For instance, Kochenderfer and Ladd (1996) found no relation between being bullied and subsequent academic achievement in their study of students assessed in the fall and spring of kindergarten, nor did Rueger and Jenkins (2014) in their study of seventh and eighth graders assessed in the fall and spring of one academic year. Feldman and colleagues (2014) also reported no association between being a target of bullying and academic achievement in their 5-year longitudinal study of youth ages 11-14. Poor academic performance can also be a predictor of peer victimization ( Vaillancourt et al., 2013b ). The authors found that poor writing performance in third grade predicted increased bullying behavior in fifth grade that was stable until the end of eighth grade.

The longitudinal associations between peer victimization and school attendance are also equivocal, with some showing positive associations ( Baly et al., 2014 ; Buhs et al., 2006 ; Gastic, 2008 ; Kochenderfer and Ladd, 1996 ; Smith et al., 2004 ) and others not finding a statistically significant association ( Forero et al., 1999 ; Glew et al., 2008 ; Rueger et al., 2011 ; Vaillancourt et al., 2013b ). 10

In summary, there have been a number of cross-sectional and longitudinal studies that have provided support for a relation between being bullied and increased risk for poor academic achievement. However, given the inconsistent results found with longitudinal studies, more research is warranted in this area to more fully ascertain the relation between being bullied and academic achievement over time.

  • CONSEQUENCES FOR INDIVIDUALS WHO BULLY

There is evidence that supports a finding that individuals who bully others have contradictory attributes ( Institute of Medicine and National Research Council, 2014a ; Vaillancourt et al., 2010b ). Research suggests that there are children and adolescents who bully others because they have some form of maladjustment ( Olweus, 1993a ) or, as mentioned in Chapter 3 , are motivated by establishing their status in a social network ( Faris and Ennett, 2012 ; Rodkin et al., 2015 ; Sijtsema et al., 2009 ; Vaillancourt et al., 2003 ). Consequently, the relation between bullying, being bullied, acceptance, and rejection is complex ( Veenstra et al., 2010 ). This complexity is also linked to a stereotype held by the general public about individuals who bully. This stereotype casts children and youth who bully others as being high on psychopathology, low on social skills, and possessing few assets and competencies that the peer group values ( Vaillancourt et al., 2010b ). Although some occurrence of this “stereotypical bully” or “classic bully” is supported by research ( Kumpulainen et al., 2001 ; Olweus, 1993a ; Sourander et al., 2007 ), when researchers consider social status in relation to perpetration of bullying behavior, a different profile emerges. These studies suggest that most children and youth who bully others wield considerable power within their peer network and that high-status perpetrators tend to be perceived by peers as being popular, socially skilled, and leaders ( de Bruyn et al., 2010 ; Dijkstra et al., 2008 ; Peeters et al., 2010 ; Thunfors and Cornell, 2008 ; Vaillancourt et al., 2003 ). High-status bullies have also been found to rank high on assets and competencies that the peer group values such as being attractive or being good athletes ( Farmer et al., 2003 ; Vaillancourt et al., 2003 ); they have also been found to rank low on psychopathology and to use aggression instrumentally to achieve and maintain hegemony (for reviews, see Rodkin et al., 2015 , and Vaillancourt et al., 2010b ). Considering these findings of contrasting characteristics of perpetrators of bullying behavior, it makes sense that the research on outcomes of perpetrating is mixed. Unfortunately, most research on the short- and long-term outcomes of perpetrating bullying behavior has not taken into account this heterogeneity when considering the impact to children and youth who have bullied their peers.

Psychosomatic Consequences

Findings from cross-sectional studies that reported data on individuals who bullied others have shown that these individuals are at risk of developing psychosomatic problems ( Gini, 2008 ; Srabstein et al., 2006 ). Gini and Pozzoli (2009) conducted a meta-analysis to test whether children involved in bullying behavior in any role are at risk for psychosomatic problems. They included studies ( n = 11) that examined the association between bullying involvement and psychosomatic complaints in children and adolescents between the ages of 7 and 16. The studies included in the meta-analysis used self-report questionnaires; reports from peers, parents, or teachers; and clinical interviews that resulted in a clinical rating of the subject's behaviors and health problems. The included studies also had enough information to calculate effect sizes. An analysis of six studies that met the selection criteria revealed that children who bully had a higher risk ( OR = 1.65, 95% CI [1.34, 2.04]) of exhibiting psychosomatic problems than their uninvolved peers.

This meta-analysis was limited because of its inclusion of cross-sectional and observational studies. Such studies do not allow firm conclusions on cause and effect; hence, the association between bullying perpetration and psychosomatic problems may be difficult to interpret. The methodologies used in the studies make them susceptible to bias and misclassification due to the reluctance of individuals who bully to identify themselves as perpetrators of bullying behavior. Also, the different forms of victimization included in the underlying studies were not reported in this meta-analysis. Additional research is needed to examine the involvement in perpetrating bullying behavior and its short- and long-term psychosomatic consequences.

Psychotic Problems

Using a population-based cohort study, Wolke and colleagues (2014) examined whether bullying perpetration and being a target of bullying in elementary school predicted psychotic experiences 11 in adolescence. The authors assessed 4,720 individuals between the ages of 8 and 11 who were involved in bullying either as perpetrators or targets. At age 18, suspected or definite psychotic experiences were assessed using semistructured interviews. After controlling for the child's gender, intelligence quotient at age 8, and childhood behavioral and emotional problems, the researchers found that both individuals who are bullied (child report at age 10: OR = 2.4, 95% CI [1.6, 3.4]; mother report: OR = 1.6, 95% CI [1.1, 2.3]) and individuals who bullied others (child report at age 10: OR = 4.9, 95% CI [1.3, 17.7]; mother report: OR = 1.2, 95% CI [0.46, 3.1]) had a higher prevalence of psychotic experiences at age 18. The authors concluded that “involvement in any role in bullying may increase the risk of developing psychotic experiences in adolescence” ( Wolke et al., 2014 , p. 2208).

In summary, several studies have focused on the consequences of bullying for individuals who are bullied and have also reported more broadly on consequences for perpetrators of aggressive behavior (see Gini and Pozzoli, 2009 ; Lereya et al., 2015 ; Reijntjes et al., 2010 ; Ttofi et al., 2011 ), but the consequences of bullying involvement for individuals who perpetrate bullying behavior have been rarely studied to date. That is, although there is a rich literature on aggressors and the outcomes of being aggressive, there are few studies examining bullying perpetration specifically, taking into account the power imbalance, repetition, and intentionality that differentiates aggression from bullying from other forms of peer aggression. As discussed in Chapter 2 , the available research on the prevalence of bullying behavior focuses almost entirely on the children who are bullied. More research, in particular longitudinal research, is needed to understand the short- and long-term physical health, psychosocial, and academic consequences of bullying involvement on the individuals who have a pattern of bullying others, when those individuals are distinguished from children who engage in general aggressive behavior.

  • CONSEQUENCES FOR INDIVIDUALS WHO BULLY AND ARE ALSO BULLIED

Individuals who bully and are also bullied experience a particular combination of consequences that both children who are only perpetrators and children who are only targets also experience, such as comorbidity of both externalizing and internalizing problems, negative perception of self and others, poor social skills, and rejection by the peer group. However, at the same time this combination of roles in bullying is negatively influenced by the peers with whom they are interacting ( Cook et al., 2010 ). After controlling for adjustment problems existing prior to incidents of bullying others or being bullied, a nationally representative cohort study found that young children who have been both perpetrators and targets of bullying tended to develop more pervasive and severe psychological and behavioral outcomes than individuals who were only bullied ( Arseneault et al., 2006 ).

Adolescents who were involved in cyberbullying as both perpetrators and targets have been found to be most at risk for negative mental and physical health consequences, compared to those who were only perpetrators, those who were only targets, or those who only witnessed bullying ( Kowalski and Limber, 2013 ; Nixon, 2014 ). For example, the results from a study by Kowalski and Limber (2013) that examined the relation between children's and adolescents' experiences with cyberbullying or traditional bullying and outcomes of psychological health, physical health, and academic performance showed that students who were both perpetrators and targets had the most negative scores on most measures of psychological health, physical health, and academic performance, when compared to those who were only perpetrators, only targets, or only witnesses of bullying incidents.

Wolke and colleagues (2001) examined the association of direct and relational bullying experience with common health problems and found that students ages 6-9 who bullied others and were also bullied by others had more physical health symptoms than children who were only perpetrators or were not involved in bullying behavior. Hunter and colleagues (2014) evaluated whether adolescents who were involved in bullying experienced sleep difficulties more than adolescents who were not involved. They analyzed surveys that were originally collected on behalf of the UK National Health Service and had been completed by adolescents ages 11-17. Controlling for gender, school-stage, socioeconomic status, ethnicity, and other factors known to be associated with sleep difficulties—alcohol consumption, tea or coffee consumption, and illegal drug use—the authors found that individuals who were both perpetrators and targets in bullying incidents were almost three times more likely ( OR = 2.90, 95% CI [1.17, 4.92]) to experience these sleep difficulties, compared to uninvolved young people. Additional research is needed to identify the mechanisms underlying short- and long-term physical health outcomes of individuals who bully and are also bullied.

There is evidence that individuals who are both perpetrators and targets of bullying have the poorest psychosocial profile among individuals with any involvement in bullying behavior; their psychosocial maladjustment, peer relationships, and health problems are similar to individuals who are only bullied, while their school bonding and substance use is similar to individuals who are only perpetrators ( Graham et al., 2006 ; Nansel et al., 2001 , 2004 ). Individuals who both bully and are also bullied by others experience a greater variety of both internalizing and externalizing symptoms than those who only bully or those who are only bullied ( Kim et al., 2006 ).

Some meta-analyses have examined the association between involvement in bullying and internalizing problems in the school-age population and concluded that that individuals who are both perpetrators and targets of bullying had a significantly higher risk for psychosomatic problems than individuals who were only perpetrators or who were only targets ( Gini and Pozzoli, 2009 ; Reijntjes et al., 2010 ). In their meta-analysis, Gini and Pozzoli (2009) reviewed studies that examined the association between involvement in bullying and psychosomatic complaints in children and adolescents. Analysis of a subgroup of studies ( N = 5) that reported analyses for individuals who bully and are also bullied by others showed that these individuals have a significantly higher risk for psychosomatic problems than uninvolved peers ( OR = 2.22, 95% CI [1.77, 2.77]).

Studies suggest that individuals who bully and who are also bullied by others are especially at risk for suicidal ideation and behavior, due to increased mental health problems (see Holt et al., 2015 , and Box 4-1 ).

Suicidality: A Summary of the Available Meta-Analyses.

Similar to individuals who bully, individuals who bully and are also bullied by others often demonstrate heightened aggression compared with non-involved peers. Compared to these other groups, they are by far the most socially ostracized by their peers, most likely to display conduct problems, and least engaged in school, compared with those who are either just perpetrators or just targets; they also report elevated levels of depression and loneliness ( Juvonen et al., 2003 ). Additional research is needed that examines the unique consequences of those children and youth characterized as “bully-victims” because often they are not separated out from “pure victims” (those who are bullied only) in studies. School shootings are a violent externalizing behavior that has been associated with consequences of bullying behavior in the popular media (see Box 4-2 for additional detail).

Bullying and School Shootings.

Several studies have examined the associations between bullying involvement in adolescence and mental health problems in adulthood and have found that individuals who have bullied others and have also been bullied had increased risk of high levels of critical symptoms of psychosis compared to non-involved peers ( Gini, 2008 ; Sigurdson et al., 2015 ). Research is limited in this area, and the topic warrants further investigation.

  • CONSEQUENCES OF BULLYING FOR BYSTANDERS

Bullying cannot be viewed as an isolated phenomenon; it is intertwined within the particular peer ecology that emerges, an ecology constituted of social processes that serve particular functions for the individual and for the group ( Rodkin, 2004 ). Bullying frequently occurs in the presence of children and youth who are bystanders or witnesses. Research indicates that bullying can have significant adverse effects on these bystanders ( Polanin et al., 2012 ).

Bystanders have reported feelings of anxiety and insecurity ( Rigby and Slee, 1993 ) which stemmed, in part, from fears of retaliation ( Musher-Eizenman et al., 2004 ) and which often prevented bystanders from seeking help ( Unnever and Cornell, 2003 ). In a study to explore the impact of bullying on the mental health of students who witness it, Rivers and colleagues (2009) surveyed 2,002 students, ages 12-16 and attending 14 schools in the United Kingdom, using a questionnaire that included measures of bullying at school, substance abuse, and mental health risk. They found that witnessing bullying significantly predicted elevated mental health risks even after controlling for the effect of also being a perpetrator or victim (range of = .07 to .15). They also found that being a witness to the bullying predicted elevated levels (= .06) of substance use. Rivers and Noret (2013) found that, compared to students who were not involved in bullying, those who observed bullying reported more symptoms of interpersonal sensitivity (e.g., feelings of being hurt or inferior), helplessness, and potential suicide ideation.

In conclusion, there is very limited research available on the consequences of witnessing bullying for those children and youth who are the bystanders. Studies of bystander behavior have traditionally sought to understand their motives for participation in bullying ( Salmivalli, 2010 ), their roles ( Lodge and Frydenberg, 2005 ; Salmivalli et al., 1996 ), their behavior (either reinforcing the bully or defending the victim) in bullying situations ( Salmivalli et al., 2011 ), and why observers intervene or do not intervene ( Thornberg et al., 2012 ) from a social dynamic perspective, without exploring the emotional and psychological impact of witnessing bullying. More research is needed to understand these consequences.

MULTIPLE EXPOSURES TO VIOLENCE 12

One subpopulation of school-aged youth that may be at increased risk for detrimental short- and long-term outcomes associated with bullying victimization is poly-victims. Finkelhor and colleagues (2007) coined the terms “poly-victim” and “poly-victimization” to represent a subset of youth who experience multiple victimizations of different kinds—such as exposure to (1) violent and property crimes (e.g., assault, sexual assault, theft, burglary), (2) child welfare violations (child abuse, family abduction), (3) the violence of warfare and civil disturbances, and (4) being targets of bullying behavior—and who manifest high levels of traumatic symptomatology. The identification of a poly-victim is grounded not only in the frequency of the victimization but also in victimization across multiple contexts and perpetrators ( Finkelhor et al., 2007 , 2009 ).

Ford and colleagues (2010) determined that poly-victims were more likely to meet criteria for psychiatric disorder, including being two times more likely to report depressive symptoms, three times more likely to report posttraumatic stress disorder, up to five times more likely to use alcohol or drugs, and up to eight times more likely to have comorbid disorders, compared to youth that did not meet criteria for poly-victimization. Poly-victims often engaged in delinquent behavior, associated with deviant peers ( Ford et al., 2010 ), and were entrenched within the juvenile justice system ( Ford et al., 2013 ). Students who were poly-victims in the juvenile justice system reported higher levels of traumatic symptomatology ( Finkelhor et al., 2005 ). However, it is currently unclear whether being bullied plays a major or minor role in poly-victimization.

  • MECHANISMS FOR THE PSYCHOLOGICAL EFFECTS OF BULLYING

In the following sections, the committee describes five potential mechanisms for the psychological effects of bullying behavior for both the children who are bullied and children who bully. These include self-blame, social cognition, emotional dysregulation, genetic predisposition to mental health outcomes and bullying, and telomere erosion. 13

One important mechanism for the psychological effects of bullying is how the targets of bullying construe the reason for their plight ( Graham, 2006 ). For example, a history of bullying and the perception of being singled out as a target might lead an individual to ask “Why me ?” In the absence of disconfirming evidence, some might come to blame themselves for their peer relationship problems. Self-blame and accompanying negative affect can then lead to many negative outcomes, including low self-esteem, anxiety, and depression ( Graham and Juvonen, 1998 ).

The adult rape literature (another form of victimization) highlights a correlation between experiencing rape and self-attributions that imply personal deservingness, labeled characterological self-blame, since they may lead to the person thinking of themselves as chronic victims ( Janoff-Bulman, 1979 ). From an attributional perspective, characterological self-blame is internal and therefore reflects on the self; it is stable and therefore leads to an expectation that harassment will be chronic; and it is uncontrollable, suggesting an inability to prevent future harassment. Attributing negative outcomes to internal, stable, and uncontrollable causes leads individuals to feel both hopeless and helpless ( Weiner, 1986 ). In contrast, behavioral self-blame (e.g., “I was in the wrong place at the wrong time”) implies a cause that is both unstable (the harassment is not expected to occur again) and controllable (there are responses in one's repertoire to prevent future harassment). Several researchers in the adult literature have documented that individuals who make characterological self-blaming attributions for negative outcomes cope more poorly, feel worse about themselves, and are more depressed than individuals who make attributions to their behavior (see Anderson et al., 1994 ). Research with early adolescents also revealed that characterological self-blame for academic and social failure resulted in heightened depression ( Cole et al., 1996 ; Tilghman-Osborne et al., 2008 ).

In the first attribution study focused specifically on bullying, Graham and Juvonen (1998) documented that sixth grade students with reputations as targets made more characterological self-blaming attributions for harassment than behavioral self-blaming attributions. Characterological self-blame, in turn, partly mediated the relationship between victim status and psychological maladjustment as measured by depression and social anxiety. Many studies since then have documented the relation between being targets of bullying, characterological self-blame, and maladjustment ( Graham et al., 2006 , 2009 ; Perren et al., 2012 ; Prinstein et al., 2005 ). Furthermore, bullied youth who endorsed characterological self-blame were likely to develop negative expectations about the future, which may also increase risk for continued bullying. For example, Schacter and colleagues (2014) reported that characterological self-blame endorsed in the fall of sixth grade predicted increases in reports of being bullied in the spring of sixth grade. Self-blame can then instigate psychological distress over time as well as increases in experiences of being bullied.

Such findings have implications for interventions targeted at bullied youth. The goal would be to change targets' maladaptive thoughts about the causes of their plight. For example, one could seek more adaptive attributions that could replace characterological self-blame. In some cases, change efforts might target behavioral explanations for being bullied (e.g., “I was in the wrong place at the wrong time”). In such cases, the goal would be to help targeted youth recognize that they have responses in their repertoire to prevent future encounters with harassing peers—that is, the cause is unstable and controllable ( Graham and Bellmore, 2007 ). External attributions also can be adaptive because they protect self-esteem ( Weiner, 1986 ). Knowing that others are also victims or that there are some aggressive youth who randomly single out unsuspecting targets can help lessen the tendency to self-blame ( Graham and Bellmore, 2007 ; Nishina and Juvonen, 2005 ). This approach of altering dysfunctional thoughts about oneself to produce changes in affect and behavior has produced a rich empirical literature on attribution therapy in educational and clinical settings (see Wilson et al., 2002 ). The guiding assumption of that research can be applied to alleviating the plight of targets of bullying.

Social Cognition

The most commonly cited models of social cognitive processes often connect back to work by Bandura (1973) , as well as to more recent conceptualizations by Crick and Dodge (1994) . These models have been applied to understanding aggressive behavior, but there has been less research applying these models to bullying behavior specifically. Related research by Anderson and Bushman (2002) on their general aggression model allows for a more focused understanding of the thoughts, feelings, and behaviors that contribute to the development of the negative outcome. This framework characterizes the inputs, the routes, the proximal processes, and the outcomes associated with aggressive behavior and either being targeted by or perpetrating bullying behavior ( Kowalski and Limber, 2013 ; Vannucci et al., 2012 ). Although these theories pertain to aggressive behavior more broadly, given that bullying is considered by most researchers to be a specific form of aggressive behavior, these broader theories may also improve understanding of the etiology and development of bullying. For example, research on hostile attribution bias suggests that aggressive youth are particularly sensitive to ambiguous and potentially hostile peer behaviors. Similar hypersensitivity to threat is also likely present in youth who bully.

Another particular element of social cognitive processes that has been linked with aggressive behavior is normative beliefs about aggressive retaliation ( Crick and Dodge, 1994 ; Huesmann and Guerra, 1997 ). Such beliefs include the belief that aggressive retaliation is normative, acceptable, or justified, given the context of provocation. There has been exploration of links between these beliefs and both reactive and proactive aggression. However, there has been relatively limited research specifically focused on bullying behavior. Yet, the available literature suggests that although it may seem as if targets of bullying would most likely endorse such attitudes, it is the perpetrators of bullying, including those who are involved in bullying as both a perpetrator and a target, who are mostly likely to support aggressive retaliation ( Bradshaw et al., 2009 , 2013 ; O'Brennan et al., 2009 ).

Emotion Dysregulation

Attempts to identify mechanisms linking bullying to adverse outcomes have largely focused on social-cognitive processes ( Dodge et al., 1990 ) as described above. More recently, researchers have begun to examine emotion dysregulation as an additional mechanism that explains associations between peer victimization and adverse outcomes. Emotion regulation refers to the strategies that people use to “increase, maintain, or decrease one or more components of an emotional response” ( Gross, 2001 , p. 215). One's choices among such strategies have implications not only for how robustly one responds to a stressor but also for how quickly one can recover from a stressful experience. Several studies have shown that emotion regulation difficulties—also called emotion dysregulation —increase youths' risk of exposure to peer victimization ( Hanish et al., 2004 14 ) and to bullying ( Mahady Wilton et al., 2000 ). However, it is important to understand whether peer victimization itself causes emotion regulation difficulties, which in turn predict the adverse outcomes that result from peer victimization (e.g., depression, aggressive behaviors).

Several lines of evidence support the hypothesis that emotion dysregulation may account for the relationship between peer victimization and adverse outcomes among adolescents. First, constructs that are related to peer victimization—including social exclusion ( Baumeister et al., 2005 ) and stigma ( Inzlicht et al., 2006 )—impair self-regulation. Second, chronic stress during childhood and adolescence leads to deficits in emotion regulation ( Repetti et al., 2002 ). Bullying has been conceptualized as a chronic stressor for children who are the perpetrators and the targets ( Swearer and Hymel, 2015 ), which in turn may disrupt emotion regulation processes. Third, laboratory-based studies have indicated that peer victimization is associated with emotion dysregulation (e.g., self-directed negative emotion, emotional arousal and reactivity) in the context of a novel peer interaction ( Rudolph et al., 2009 ) and in a contrived play-group procedure ( Schwartz et al., 1993 ). Over time, the effort required to manage the increased arousal and negative affect associated with peer victimization 15 may eventually diminish individuals' coping resources and therefore their ability to understand and adaptively manage their emotions, leaving them more vulnerable to adverse outcomes ( McLaughlin et al., 2009 ).

Several studies have provided empirical support for emotion dysregulation as a mediator of the association between peer victimization and adverse outcomes among adolescents. In one of the first longitudinal demonstrations of mediation, McLaughlin and colleagues (2009) , using data from a large, prospective study of adolescents (ages 11-14), showed that peer victimization at baseline predicted increases in emotion dysregulation four months later, controlling for initial levels of emotion dysregulation. In turn, emotion dysregulation predicted subsequent psychological distress (depressive and anxious symptoms), thereby mediating the prospective relationship between peer victimization (relational and reputational forms) and internalizing symptoms ( McLaughlin et al., 2009 ). Subsequent research from this same sample of adolescents showed that emotion dysregulation also mediated the prospective relationship between peer victimization and subsequent aggressive behavior ( Herts et al., 2012 ).

There is also emerging evidence that emotion regulation mediates relationships between bullying and adverse outcomes. In one example of this work, Cosma et al. (2012) examined associations between bullying and several emotion regulation strategies, including rumination, catastrophizing, and other-blaming, in a sample of adolescents. Although bullying was predictive for each of these emotion regulation strategies, only one (catastrophizing) mediated the relationship between being a target of bullying and subsequent emotional problems. Thus, while more research is needed, existing evidence suggests that both social-cognitive and emotion regulation processes may be important targets for preventive interventions among youths exposed to peer victimization and bullying.

Genetic Predisposition to Mental Health Outcomes and Bullying

Longitudinal research suggests that being the victim or perpetrator of bullying does not lead to the same pathological or nonpathological outcomes in every person ( McDougall and Vaillancourt, 2015 ). There are many factors that contribute to how a person responds to the experience of being victimized, with very strong links already established with life experiences, as reviewed above. Most studies examining heterogeneity in outcomes associated with bullying have focused on environmental characteristics, such as individual, family, and school-level features to explain why some individuals fare better or worse when involved with bullying ( Vaillancourt et al., in press ). For example, the moderating role of the family has been examined with results indicating that bullied children and youth with better home environments tend to fare better than those living with more complicated families ( Flouri and Buchanan, 2003 ; also see Chapter 3 of this report). Far fewer studies have examined the role of potential genetic influences as mediators between life experiences such as bullying and mental health outcomes. Identifying potential genetic influences is critical for improving understanding of the rich behavioral and epidemiological data already gathered. At the present time, evidence-based understanding of physiology and neuroscience is very limited, and insufficient data have been gathered to produce informed hypothesis testing.

There is a growing body of literature examining the relative role of genes' interaction with the environment in relation to experiences with trauma. However, there are fewer studies exploring potential relations between genes and being the target or perpetrator of bullying. At first glance these studies may appear to suggest that a person's involvement with bullying is predetermined based on his/her genetic profile. Yet, it is important to bear in mind that heritable factors are also associated with specific environments—meaning it is difficult to separate genetic effects from environmental effects. This is a phenomenon termed gene-environment correlations , abbreviated as rGE ( Brendgen, 2012 ; Plomin et al., 1977 ; Scarr and McCartney, 1983 ). For example, aggression, which is highly heritable ( Niv et al., 2013 ), can be linked to the selection of environments in different ways (for review, see Brendgen, 2012 ). Aggressive children may choose friends who are similar in their genetically influenced behavioral characteristic of being aggressive, and this type of selection influences the characteristics of their peer group ( Brendgen, 2012 , p. 420). This is an example of selective rGE. A child's genetically influenced characteristic to be aggressive can also produce a negative reaction from others, such as being disliked. This environmental variable of being rejected now “becomes correlated with the aggressive genotype” ( Brendgen, 2012 , p. 421). This is an example of evocative rGE. Another way that a person's genetic predisposition can be correlated with their environment is through a more passive process, called a passive rGE ( Brendgen, 2012 ). For example, aggressive parents may be more likely to live in high-crime neighborhoods, which influence the probability that their child will be associating with antisocial peers. These important rGE processes and confounds of interaction notwithstanding, it is worth mentioning that the research on the genetics of being a target or perpetrator of bullying is still in its infancy, and caution is needed when evaluating the results, as replication is much needed in this area. Before considering these studies, the committee first reviews the concept of how genetic differences influence behavior because it is important to clarify new concepts in this burgeoning area of science (see Box 4-3 ).

How Do Genes Influence Behavior?

With this backdrop in mind, the committee focused on twin studies of familial (family environment) versus genetic influence, gene by environment interaction, and a newer area of inquiry, epigenetics: the study of cellular and physiological phenotypic trait variations caused by external or environmental factors.

Twin Studies

Twin studies are routinely used to examine the relative influence of genetics and the environment on a particular phenomenon, such as being the target or perpetrator of bullying. In these studies, the causes of phenotypic variation (for example the variation in being a target or perpetrator of bullying) is separated into three components: (1) the additive genetic component or the heritable factor; (2) the shared environment component or the aspect of the environment twins share such as poor family functioning; and (3) the nonshared environment component or the aspect of the environment that is unique to each twin, such as the classroom if twins are in different classes.

Studies that decompose the unique effects of the environment and genetics on bullying behavior are best illustrated by two examples. Using data from the Environmental Risk (E-Risk) Longitudinal Twin Study, a study of high-risk 16 British twins reared together and apart, Ball and colleagues (2008) examined children's involvement in bullying and the genetic versus environmental contributions associated with their involvement. The twins in this study were assessed at ages 7 and 10 on their experiences with bullying, using teacher and parent reports. Results indicated that 73 percent of the variation in being the target of bullying and 61 percent of the variation in bullying perpetration were accounted for by genetic factors. In another study of Canadian twins reared together and assessed at age 7, using teacher and peer reports to assess peer victimization and aggression, Brendgen and colleagues (2008) found that for girls, 60 percent of the variation in aggression was accounted for by genetic factors and for boys, the variation estimate was 66 percent. For peer victimization, the Canadian study found that genetics did not play a role in the prediction of being targeted by peers. In fact, almost all of the variance was accounted for by environmental factors—29 percent of the variance in peer victimization was from the shared environment and 71 percent from the nonshared environment. The authors concluded that “genetic modeling showed that peer victimization is an environmentally driven variable that is unrelated to children's genetic disposition” ( Brendgen et al., 2008 , p. 455).

These two studies address the role genetics might play in the expression of aggressive behavior but conflict on the heritability of being a target of bullying. Most studies examining the heritability of externalizing problems, which includes studies on perpetrating aggression and bullying, report high heritability estimates. In fact, a recent meta-analysis found that aggression and rule-breaking were highly influenced by genetics, estimating the heritability rate at 41 percent ( Niv et al., 2013 ). Moreover, studies have found that the heritability estimates tend to be higher for more serious forms of antisocial behavior. For example, the heritability of psychopathy in 7-year-old British twin children reared together and apart and studied in the Twins Early Development Study was reported to be 81 percent ( Viding et al., 2005 ). However, estimates of the heritability of peer victimization vary across studies, as illustrated by the above results from Ball and colleagues (2008) contrasted with those from Brendgen and colleagues (2008) , and even within studies ( Brendgen et al., 2008 , 2013 ).

Brendgen and colleagues have since revised their assessment about the role genetics play in the prediction of being the target of bullying. In a more recent study, following the same children highlighted in the 2008 paper ( Brendgen et al., 2008 ) across three assessment periods (kindergarten, grade 1, and grade 4), Boivin and colleagues (2013) reported that at each grade, among twins who were reared together and apart, genetic factors accounted for a notable percentage of the variance in children's difficulties with peers. Peer difficulties were assessed as a latent factor derived from self-, teacher-, and peer-reports of peer victimization 17 and peer rejection. Specifically, in kindergarten and grade 1, 73 percent of the variance was accounted by genetic factors and in grade 4, genetic factors account for 94 percent of the variance in peer rejection and victimization.

There are several reasons for discrepancies between and within studies of the genetic contribution to bullying behavior. One reason is related to how peer victimization is assessed. Parent-, teacher-, peer-, and self-reports of bullying victimization have been shown to vary considerably across reporters ( Ostrov and Kamper, 2015 ; Patton et al., 2015 ; Shakoor et al., 2011 ); thus, the method used to assess involvement with bullying may lead to different results. Another reason for the differences may be related to development. The influence of the environment is expected to change as children age. Young children are particularly sensitive to family influences, while the influence of peers tends to matter more during adolescence ( Harris, 1995 ). Moreover, the type of environment a person is exposed to (i.e., harsh or nurturing) interacts with genes to produce a brain that is tailored to deal with the particular demands of that environment.

Taken together, the genetic studies reviewed suggest that aggression, which characterizes the perpetrator role in bullying ( Vaillancourt et al., 2008 ), might have heritable components, but the findings on being the target of bullying or other aggressive behavior are mixed. Thus, the role of genetic influences on both perpetrating and being a target of bullying requires more empirical attention before conclusions can be drawn.

Gene-by-Environment Interactions

Researchers also question whether specific genotypic markers of vulnerability (e.g., candidate genes) influence developmental outcomes in the face of adversity (i.e., environment). Importantly, there is some indication that genetics influences the mental health issues related to bullying highlighted above, such as depression and heightened aggression. For example, in gene-environment studies, candidate genes have been examined as moderators of the exposure to a toxic stressor such as child maltreatment and health outcomes such as depression. When the body experiences repeated bouts of stress that fail to resolve quickly, the heightened state of vigilance and preparedness depletes it of resources and the stress hormone cortisol begins to produce adverse effects. Specifically, prolonged stress disrupts brain functions and results in compromised decision making, faulty cognitive assessment, compromised learning and memory, and a heightened sense of threat that alters behavior ( Lupien et al., 2005 ; McEwen, 2014 ). There is evidence that the impact of changes in cortisol (either too high or too low) on learning may contribute, in part, to bullied children's decline in academic performance ( Vaillancourt et al., 2011 ), overeating/metabolic disorder, or emotional dysregulation, but this research is relatively new and needs to be explicitly explored within the context of bullying ( McEwen, 2014 ).

A paradigmatic example of this type of study is one by Caspi and colleagues (2003) , in which the moderating role of a functional polymorphism in the promoter region of the serotonin transporter gene 5-HTTLPR was examined in relation to exposure to maltreatment in childhood and depression in adulthood. Results indicated that depression rates were far greater among abused individuals if they had two copies of the short allele. 18 Among individuals with a long allele, depression rates were lower, suggesting that the long allele was protective, while the short allele was a risk factor for depression in the face of adversity. Although the exact role of this serotonin-related gene has been a subject of controversy, a meta-analysis concluded that overall, the results are consistent across studies ( Karg et al., 2011 ). Nevertheless, skepticism and controversy remain regarding studies of gene-environment interactions ( Dick et al., 2015 ; Duncan, 2013 ; Duncan and Keller, 2011 ; Duncan et al., 2014 ). This important debate notwithstanding, there is evidence that variations in genotype might moderate the relation between exposure to being bullied and health outcomes. For example, Sugden and colleagues (2010) found that bullied children who carried two short versions of the 5-HTTLPR gene were more likely to develop emotional problems than bullied children who carried the long allele. Importantly, this moderating effect was present even when pre-victimization emotional problems were accounted for statistically. In addition to this study, three other studies have demonstrated the moderating effect of the 5-HTTLPR gene in the bullying-health link ( Banny et al., 2013 ; Benjet et al., 2010 ; Iyer et al., 2013 ), with depression being worse for carriers of the short/short genotype (both alleles are the short version) than carriers of the short/long and long/long genotypes.

Although the evidence suggests that genotypes moderate the relation between being a target of bullying and poorer mental health functioning like depression, it is important to acknowledge that this relation is more complex. Indeed, some individuals may be particularly biologically sensitive to negative environmental influences such as being bullied, but this genetic vulnerability can also be linked to better outcomes in the context of a more supportive and enriched environment (see Vaillancourt et al., in press ). This phenomenon is termed differential susceptibility ( Belsky and Pluess, 2009 ; Boyce and Ellis, 2005 ). For example, in their study of 5 and 6-year old children, Obradovic and colleagues (2010) found that high stress reactivity as measured using respiratory sinus arrhythmia and salivary cortisol was linked to poorer socioemotional behavior in the context of being in an environment that was high in family adversity. In a context characterized by lower adversity, high stress-reactive children had more adaptive outcomes.

To the committee's knowledge, there are no studies that have examined bullying perpetration in relation to serotonin transporter polymorphisms, although there are studies that have examined this polymorphism in aggressive and non-aggressive children. For example, Beitchman et al. (2006) examined 5-HTTLPR in clinically referred children between the ages of 5 and 15 and found a positive association between the short/short genotype and aggression. In other studies, the short allele has been associated with problems with impulse control that includes the use of aggression ( Retz et al., 2004 ).

The moderating role of different candidate genes has also been examined in relation to exposure to childhood adversity and poorer developmental outcomes (see review by Vaillancourt et al., in press ). With respect to bullying, only a few studies have examined gene-environment interactions. In one study by Whelan and colleagues (2014) , harsh parenting was associated with increased peer victimization and perpetration, but this effect was not moderated by the Monoamine Oxidase A (MAOA) genotype. 19 In another longitudinal study, Kretschmer and colleagues (2013) found that carriers of the 4-repeat homozygous variant of the dopamine receptor D4 gene were more susceptible to the effects of peer victimization 20 on delinquency later in adolescence than noncarriers of this allele. Finally, in a large sample of post-institutionalized children from 25 countries, VanZomeren-Dohm and colleagues (2015) examined the moderating role of FKBP5 rs1360780 21 in the relation between peer victimization 22 and depression symptoms. In this study, gender was also found to be a moderator. Specifically, girls who had the minor genotype (TT or CT) were more depressed at higher levels of peer victimization, but less depressed at lower level of peer victimization than girls who had CC genotype. For boys, the CC genotype was associated with more symptoms of depression than girls with the same CC genotype who had been bullied.

It is clear that genetics influences how experiences contribute to mental and physical well-being, although the specifics of these gene-environment interactions are complex and not completely understood. Even though genes appear to modulate humans' response to being a target or a perpetrator of bullying behavior, it is still unclear what aspects of these experiences are interacting with genes and which genes are implicated to produce the variability in outcomes. Human genes and environment interact in a very complex manner: what biological events a particular gene influences can change at different stages of development. That gene therefore interacts with the environment in unique ways across the development timeline. These gene-environment interactions can be subtle and are under constant flux ( Lake and Chan, 2015 ). Knowing both the genes involved and the specific environment conditions is critically important to understanding these interactions; a simplistic view of either the genetic or environmental component, especially when considered in isolation from the behavioral literature, is unlikely to be productive.

Epigenetic Consequences

It is clear from the research reviewed here that there are a variety of pathways leading to adaptive and maladaptive endpoints and that these pathways can also vary within the “system” along with other conditions and attributes ( McDougall and Vaillancourt, 2015 , p. 300), including a person's genetic susceptibility. In this section, the committee focuses on studies examining how genetic susceptibility can make certain individuals more sensitive to negative environmental influences.

Although a person's DNA is fixed at conception (i.e., nonmalleable), environment can have a strong effect on how some genes are used at each of the stages of development. One way such changes in gene use and expression can occur is through an epigenetic effect, in which environmental events alter the portions of the genome that control when gene replication is turned on or off and what parts of a gene get transcribed ( McGowan et al., 2009 ; Roth, 2014 ). That is, while an individual's genetic information is critically important, the environment can help to increase or decrease how some genetic information is used by indirectly turning on or off some genes based on input received by somatic cells from the environment. Such epigenetic alterations have been empirically validated in several animal studies. For example, in one line of epigenetic studies, infant rat pups are raised with either low- or high-nurturing mothers or with mothers that treated the pups harshly. The researchers found that the type of maternal care received in infancy had a notable effect on the rats' subsequent ability to deal with stress ( McGowan et al., 2011 ; Roth and Sweatt, 2011 ; Weaver et al., 2004 ). The behavioral effects were correlated with changes in DNA methylation. 23 Epigenetic changes associated with gene-environment interactions is a new and exciting research area that provide a direct link between how our genes are read and is thought to enable us to pass our experiences to the next generations. It is helpful to think of genes as books in a library and epigenetics as placing a barrier in front of a book to decrease the chances it is read or providing easy access to the book. Thus far, research has found that certain epigenetic mechanisms are strongly correlated with different neurobehavioral developmental trajectories, including changes in vulnerability and resilience to psychopathology. How epigenetics relates to individual responses to being a target or perpetrator of bullying is not clear, but the research in related areas of behavior highlights an important emerging area for investigation.

Various epigenetic processes appear to interact with many changes in the brain produced by early life experiences, including not only the number and shape of brain cells but also how these cells connect to one another at synapses ( Hanson et al., 2015 ).

Regarding bullying, the committee identified only one study that has examined epigenetic changes. Specifically, Ouellet-Morin and colleagues (2013) found an increase in DNA methylation of the serotonin transporter gene for children who had been bullied by their peers but not in children who had not been bullied. These researchers also found that children with higher serotonin DNA methylation had a blunted cortisol response to stress, which they had previously shown changes as a consequence of poor treatment by peers ( Ouellet-Morin et al., 2011 ). That is, their 2011 study of twin children assessed at ages 5 and 10 found that being bullied was correlated with a change in how the body responds to stress. Bullied children displayed a blunted cortisol response to a psychosocial stress test. Because the design of the study involved an examination of identical twins who were discordant with respect to their experiences of being bullied (one twin was bullied while the other one was not), Ouellet-Morin and colleagues (2011) concluded that the effect could not be attributed to “variations in either genetic makeup, family environment, or other concomitant factors, nor could they be attributed to the twins' perceptions of the degree of stress experienced during the task” ( Vaillancourt et al., 2013a , p. 243).

In summary, it is important to note that there is no gene for being a perpetrator or a target of bullying behavior. Based on current knowledge of the genetics of complex social behavior, such as bullying, the genetic component of individual response is likely to involve multiple genes that interact with the environment in a complex manner. The current understanding of genetics and complex behaviors is that genes do not cause a behavior; gene-by-environment studies do not use the word “environment” the same way it is used in everyday language or even in traditional social psychology (as in Chapter 3 ). Rather, it is a construct used in a model to estimate how much variability exists in a given environment. This means that the same gene placed in different environments would yield very different percentages for gene-environment interactions. It is unclear how this information would inform our understanding of bullying.

Telomere Erosion Consequences

Epigenetic research has found that negative life experiences can alter the expression of a gene, which in turn, can confer a risk for poor outcomes. Research also suggests that the experience of being bullied is associated with telomere erosion. The end of each chromatid has been found to shorten as people age; this telomere “tail” also erodes as a function of engaging in unhealthy behavior such as smoking or being obese. Telomere erosion is also associated with certain illnesses such as cancer, diabetes, and heart disease ( Blackburn and Epel, 2012 ; Kiecolt-Glaser et al., 2011 ; Vaillancourt et al., 2013a ). Given these associations, scientists are now examining telomere erosion as a biomarker of stress exposure ( Epel et al., 2004 ), including the stress of being bullied by peers.

A recent longitudinal study by Shalev and colleagues (2013) examined telomere erosion in relation to children's exposure to violence, 24 a significant early-life stressor that is known to have long-term consequences for health. They found that exposure to violence, including being a target of bullying, was associated with telomere erosion for children assessed at age 5 and again at age 10. The sample for this study included 236 children recruited from the Environmental-Risk Longitudinal Twin Study ( Moffitt, 2002 ), 42 percent of whom had one or more exposures to violence. The study found that cumulative exposure to violence 25 is positively associated with accelerated telomere erosion in children, from baseline to follow-up, with potential impact for life-long health ( Shalev et al., 2013 ).

In this chapter, the committee reviewed and critically analyzed the available research on the physical health, psychosocial, and academic achievement consequences for children and youth who are bullied, for those who bully, for those who are both bullied and bullies, and for those who are bystanders to events of bullying. It also examined the potential mediating mechanisms of, and the genetic predisposition to, mental health outcomes associated with childhood and youth experiences of bullying behavior. Most studies are cross-sectional and thus provide only associations suggestive of a possible causal effect. This problem is most acute for studies based on anonymous self-report, in which both the independent variable (experience of bullying in one or more roles) and dependent variables (such as emotional adjustment) are data collected at the same time from sources subject to various forms of bias.

The limited amount of data from longitudinal and experimental research designs limits the ability to draw conclusions with respect to causality. Additional longitudinal studies, for example, could help establish that the negative consequences attributed to bullying were not present before the bullying occurred. But even this does not prove a causal effect, since bullying and the associated impairments might be products of some third factor. Below, the committee summarizes what is known about associations and consequences and identifies key conclusions that can be drawn from this evidence base.

  • FINDINGS AND CONCLUSIONS
Finding 4.1: Individuals who both bully and are also bullied by others experience a greater variety of both internalizing and externalizing symptoms than those who only bully or are only bullied. Finding 4.2: Individuals who bully others are likely to experience negative emotional, behavioral, and mental health outcomes, though most research has not distinguished perpetration of bullying from other forms of peer aggression. Finding 4.3: A large body of research indicates that individuals who have been bullied are at increased risk of subsequent mental, emotional, and behavioral problems, especially internalizing problems. Finding 4.4: Studies of bystander behavior in bullying have rarely examined the emotional and psychological impact of witnessing bullying. Finding 4.5: Children and youth who are bullied subsequently experience a range of somatic disturbances. Finding 4.6: Social-cognitive factors (e.g., self-blame) and unsuccessful emotion regulation (i.e., emotion dysregulation) mediate relationships between bullying and adverse outcomes. Finding 4.7: There is evidence that stressful events, such as might occur with experiences of being bullied, alter emotional brain circuits. This potential outcome is critically in need of further investigation. Finding 4.8: Genetics influences how experiences contribute to mental and physical well-being, although the nature of this relationship is complex and not completely understood. Finding 4.9: Emerging evidence suggests that repeated exposure to bullying may produce a neural signature that could underlie some of the behavioral outcomes associated with being bullied. Finding 4.10: There are limited data on the physical health consequence of bullying for those individuals who are involved in bullying as targets, perpetrators, as both targets and perpetrators, and as bystanders. Finding 4.11: Poly-victims (individuals who are targets of multiple types of aggression) are more likely to experience negative emotional, behavioral, and mental health outcomes than individuals targeted with only one form of aggression. Finding 4.12: The long-term consequences of being bullied extend into adulthood and the effects can be more severe than other forms of being maltreated as a child. Finding 4.13: Individuals who are involved in bullying (as perpetrators, targets, or both) in any capacity are significantly more likely to contemplate or attempt suicide, compared to children who are not involved in bullying. It is not known whether bystanders are at increased risk of suicidal ideation or suicide attempts. Finding 4.14: There is not enough evidence to date to conclude that being the target of bullying is a causal factor for multiple-homicide targeted school shootings, nor is there clear evidence on how experience as a target or perpetrator of bullying, or the mental health and behavior issues related to such experiences, contribute to school shootings.

Conclusions

Conclusion 4.1: Further research is needed to obtain more in-depth evidence on the physical health consequences of being the target of bullying including neural consequences. Conclusion 4.2: Additional research is needed to examine mediators of short- and long-term physical health outcomes of individuals who are bullied. Evidence is also needed regarding how these outcomes vary over time for different groups of children and youth, why individuals with similar experiences of being bullied might have different physical health outcomes, and how physical and emotional health outcomes intersect over time. Conclusion 4.3: Although the effects of being bullied on the brain are not yet fully understood, there are changes in the stress response systems and in the brain that are associated with increased risk for mental health problems, cognitive function, self-regulation, and other physical health problems. Conclusion 4.4: Bullying has significant short- and long-term internalizing and externalizing psychological consequences for the children who are involved in bullying behavior. Conclusion 4.5: The data are unclear on the role of bullying as one of or a precipitating cause of school shootings. Conclusion 4.6: Individuals who both bully others and are themselves bullied appear to be at greatest risk for poor psychosocial outcomes, compared to those who only bully or are only bullied and to those who are not bullied. Conclusion 4.7: While cross-sectional studies indicate that children who are bullied are at increased risk for poor academic achievement relative to those who are not bullied, the results from longitudinal studies are inconsistent and warrant more research. Conclusion 4.8: Existing evidence suggests that both social-cognitive and emotion regulation processes may mediate the relation between being bullied and adverse mental health outcomes. Conclusion 4.9: Although genes appear to modulate humans' response to being either a target or a perpetrator of bullying behavior, it is still unclear what aspects of these experiences are interacting with genes and which genes are implicated to produce the variability in outcomes. Examining the role of genes in bullying in the context of the environment is essential to providing meaningful information on the genetic component of individual differences in outcomes from being a target or a perpetrator of bullying behavior.
  • Anderson CA, Bushman BJ. Human aggression. Annual Review of Psychology. 2002; 53 (1):27–51. [ PubMed : 11752478 ]
  • Anderson CA, Miller RS, Riger AL, Dill JC, Sedikides C. Behavioral and characterological attributional styles as predictors of depression and loneliness: Review, refinement, and test. Journal of Personality and Social Psychology. 1994; 66 (3):549–558. [ PubMed : 8169764 ]
  • Archer J. Testosterone and human aggression: An evaluation of the challenge hypothesis. Neuroscience and Biobehavioral Reviews. 2004; 30 (3):319–345. [ PubMed : 16483890 ]
  • Arseneault L, Walsh E, Trzesniewski K, Newcombe R, Caspi A, Moffitt T. Bullying victimization uniquely contributes to adjustment problems in young children: A nationally representative cohort study. Pediatrics. 2006; 118 (1):130–138. [ PubMed : 16818558 ]
  • Baldwin J, Arseneault L, Danese A. Childhood bullying and adiposity in young adulthood: Findings from the E-Risk Longitudinal Twin Study. Psychoneuroendocrinology. 2015; 61 :16.
  • Ball HA, Arseneault L, Taylor A, Maughan B, Caspi A, Moffitt TE. Genetic and environmental influences on victims, bullies and bully-victims in childhood. Journal of Child Psychology and Psychiatry. 2008; 49 (1):104–112. [ PubMed : 18181884 ]
  • Baly MW, Cornell DG, Lovegrove P. A longitudinal investigation of self- and peer reports of bullying victimization across middle school. Psychology in the Schools. 2014; 51 (3):217–240.
  • Bandura A. Aggression: A Social Learning Analysis. Englewood Cliffes, NJ: Prentice-Hall; 1973.
  • Banny AM, Cicchetti D, Rogosch FA, Oshri A, Crick NR. Vulnerability to depression: A moderated mediation model of the roles of child maltreatment, peer victimization, and serotonin transporter linked polymorphic region genetic variation among children from low socioeconomic status backgrounds. Development and Psychopathology. 2013; 25 (03):599–614. [ PMC free article : PMC3959105 ] [ PubMed : 23880379 ]
  • Baratta MV, Kodandaramaiah SB, Monahan PE, Yao J, Weber MD, Lin PA, Gisabella B, Petrossian N, Amat J, Kim K. Stress enables reinforcement-elicited serotonergic consolidation of fear memory. Biological Psychiatry. 2015; 79 (10):814–822. [ PMC free article : PMC4698247 ] [ PubMed : 26248536 ]
  • Barnes DC, Wilson DA. Slow-wave sleep-imposed replay modulates both strength and precision of memory. Journal of Neuroscience. 2014; 34 (15):5134–5142. [ PMC free article : PMC3983797 ] [ PubMed : 24719093 ]
  • Barra CB, Silva IN, Rodrigues TMB, Santos JLS, Colosimo EA. Morning serum basal cortisol levels are affected by age and pubertal maturation in school-aged children and adolescents. Hormone Research in Paediatrics. 2015; 83 (1):55–61. [ PubMed : 25592297 ]
  • Baumeister RF, DeWall CN, Ciarocco NJ, Twenge JM. Social exclusion impairs self-regulation. Journal of Personality and Social Psychology. 2005; 88 (4):589–604. [ PubMed : 15796662 ]
  • Beitchman JH, Baldassarra L, Mik H, Hons B, Vincenzo De Luca M, King N, Bender D, Ehtesham S, Kennedy JL. Serotonin transporter polymorphisms and persistent, pervasive childhood aggression. American Journal of Psychiatry. 2006; 163 (6):1103–1105. [ PubMed : 16741214 ]
  • Belsky J, Pluess M. Beyond diathesis stress: Differential susceptibility to environmental influences. Psychological Bulletin. 2009; 135 (6):885–908. [ PubMed : 19883141 ]
  • Belujon P, Grace AA. Regulation of dopamine system responsivity and its adaptive and pathological response to stress. Proceedings of the Royal Society of London B: Biological Sciences. 2015; 282 (1805):1–10. [ PMC free article : PMC4389605 ] [ PubMed : 25788601 ]
  • Benjet C, Thompson RJ, Gotlib IH. 5-HTTLPR moderates the effect of relational peer victimization on depressive symptoms in adolescent girls. Journal of Child Psychology and Psychiatry. 2010; 51 (2):173–179. [ PMC free article : PMC2804775 ] [ PubMed : 19754661 ]
  • Beran T. Correlates of peer victimization and achievement: An exploratory model. Psychology in the Schools. 2009; 46 (4):348–361.
  • Beran TN, Lupart J. The relationship between school achievement and peer harassment in Canadian adolescents: The importance of mediating factors. School Psychology International. 2009; 30 (1):75–91.
  • Beran TN, Hughes G, Lupart J. A model of achievement and bullying: Analyses of the Canadian National Longitudinal Survey of Children and Youth data. Educational Research. 2008; 50 (1):25–39.
  • Blackburn EH, Epel ES. Nature. 7419. Vol. 490. 2012. pp. 169–171. [ PubMed : 23060172 ]
  • Blakemore SJ. Development of the social brain in adolescence. Journal of the Royal Society of Medicine. 2012; 105 (3):111–116. [ PMC free article : PMC3308644 ] [ PubMed : 22434810 ]
  • Boden JM, van Stockum S, Horwood LJ, Fergusson DM. Bullying victimization in adolescence and psychotic symptomatology in adulthood: Evidence from a 35-year study. Psychological Medicine. 2016; 46 (6):1311–1320. [ PubMed : 26804185 ]
  • Bogart LM, Elliott MN, Klein DJ, Tortolero SR, Mrug S, Peskin MF, Davies SL, Schink ET, Schuster MA. Peer victimization in fifth grade and health in tenth grade. Pediatrics. 2014; 133 (3):440–447. [ PMC free article : PMC4530298 ] [ PubMed : 24534401 ]
  • Boivin M, Brendgen M, Vitaro F, Dionne G, Girard A, Perusse D, Tremblay RE. Strong genetic contribution to peer relationship difficulties at school entry: Findings from a longitudinal twin study. Child Development. 2013; 84 (3):1098–1114. [ PubMed : 23210840 ]
  • Booth A, Granger DA, Shirtcliff EA. Gender- and age-related differences in the association between social relationship quality and trait levels of salivary cortisol. Journal of Research on Adolescence. 2008; 18 (2):239–260.
  • Borum R, Cornell DG, Modzeleski W, Jimerson SR. What can be done about school shootings? A review of the evidence. Educational Researcher. 2010; 39 (1):27–37.
  • Bowes L, Joinson C, Wolke D, Lewis G. Peer victimisation during adolescence and its impact on depression in early adulthood: Prospective cohort study in the United Kingdom. The BMJ. 2015; 350 :1–9. [ PMC free article : PMC4452929 ] [ PubMed : 26037951 ]
  • Boyce WT, Ellis BJ. Biological sensitivity to context: I. An evolutionary-developmental theory of the origins and functions of stress reactivity. Development and Psychopathology. 2005; 17 (2):271–301. [ PubMed : 16761546 ]
  • Bradshaw CP, Sawyer AL, O'Brennan LM. A social disorganization perspective on bullying-related attitudes and behaviors: The influence of school context. American Journal of Community Psychology. 2009; 43 (3-4):204–220. [ PubMed : 19333749 ]
  • Bradshaw CP, Goldweber A, Fishbein D, Greenberg MT. Infusing developmental neuroscience into school-based preventive interventions: Implications and future directions. Journal of Adolescent Health. 2012; 51 (2):S41–S47. [ PubMed : 22794533 ]
  • Brendgen M. Genetics and peer relations: A review. Journal of Research on Adolescence. 2012; 22 (3):419–437.
  • Bradshaw CP, Goldweber A, Garbarino J. Linking social-environmental risk factors with aggression in suburban adolescents: The role of social-cognitive mediators. Psychology in Schools. 2013; 50 (5):433–450.
  • Brendgen M, Boivin M, Vitaro F, Bukowski WM, Dionne G, Tremblay RE, Pérusse D. Linkages between children's and their friends' social and physical aggression: Evidence for a gene–environment interaction? Child Development. 2008; 79 (1):13–29. [ PubMed : 18269506 ]
  • Brendgen M, Girard A, Vitaro F, Dionne G, Boivin M. Do peer group norms moderate the expression of genetic risk for aggression? Journal of Criminal Justice. 2013; 41 (5):324–330.
  • Buhs ES, Ladd GW, Herald SL. Peer exclusion and victimization: Processes that mediate the relation between peer group rejection and children's classroom engagement and achievement? Journal of Educational Psychology. 2006; 98 (1):1–13.
  • Camodeca M, Goossens FA, Schuengel C, Terwogt MM. Links between social information processing in middle childhood and involvement in bullying. Aggressive Behavior. 2003; 29 (2):116–127.
  • Casement MD, Guyer AE, Hipwell AE, McAloon RL, Hoffmann AM, Keenan KE, Forbes EE. Girls' challenging social experiences in early adolescence predict neural response to rewards and depressive symptoms. Developmental Cognitive Neuroscience. 2014; 8 :18–27. [ PMC free article : PMC3960334 ] [ PubMed : 24397999 ]
  • Casey B, Jones RM. Neurobiology of the adolescent brain and behavior: Implications for substance use disorders. Journal of the American Academy of Child & Adolescent Psychiatry. 2010; 49 (12):1189–1201. [ PMC free article : PMC3099425 ] [ PubMed : 21093769 ]
  • Caspi A, Sugden K, Moffitt TE, Taylor A, Craig IW, Harrington H, McClay J, Mill J, Martin J, Braithwaite A. Influence of life stress on depression: Moderation by a polymorphism in the 5-HTT gene. Science. 2003; 301 (5631):386–389. [ PubMed : 12869766 ]
  • Chattarji S, Tomar A, Suvrathan A, Ghosh S, Rahman MM. Neighborhood matters: Divergent patterns of stress-induced plasticity across the brain. Nature Neuroscience. 2015; 18 (10):1364–1375. [ PubMed : 26404711 ]
  • Cole DA, Peeke LG, Ingold C. Characterological and behavioral self-blame in children: Assessment and development considerations. Development and Psychopathology. 1996; 8 (02):381–397.
  • Cook CR, Williams KR, Guerra NG, Kim TE, Sadek S. Predictors of bullying and victimization in childhood and adolescence: A meta-analytic investigation. School Psychology Quarterly. 2010; 25 (2):65–83.
  • Copeland WE, Wolke D, Angold A, Costello EJ. Adult psychiatric outcomes of bullying and being bullied by peers in childhood and adolescence. Journal of the American Medical Association Psychiatry. 2013; 70 (4):419–426. [ PMC free article : PMC3618584 ] [ PubMed : 23426798 ]
  • Copeland WE, Wolke D, Lereya ST, Shanahan L, Worthman C, Costello EJ. Childhood bullying involvement predicts low-grade systemic inflammation into adulthood. Proceedings of the National Academy of Sciences of the United States of America. 2014; 111 (21):7570–7575. [ PMC free article : PMC4040559 ] [ PubMed : 24821813 ]
  • Cornell D. School Violence: Fears vs. Facts. New York: Routledge; 2006.
  • Cosma A, Balazsi R, Dobrean A, Baban A. Bullying victimization, emotional problems and cognitive emotion regulation in adolescence. Psychology & Health. 2012; 27 :185–188.
  • Cougnard A, Marcelis M, Myin-Germeys I, De Graaf R, Vollebergh W, Krabbendam L, Lieb R, Wittchen HU, Henquet C, Spauwen J. Does normal developmental expression of psychosis combine with environmental risk to cause persistence of psychosis? A psychosis proneness–persistence model. Psychological Medicine. 2007; 37 (04):513–527. [ PubMed : 17288646 ]
  • Crick NR, Dodge KA. A review and reformulation of social information-processing mechanisms in children's social adjustment. Psychological Bulletin. 1994; 115 (1):74–101.
  • Cunningham T, Hoy K, Shannon C. Does childhood bullying lead to the development of psychotic symptoms? A meta-analysis and review of prospective studies. Psychosis. 2015; 8 (1):1–12.
  • Dahl RE, Gunnar MR. Heightened stress responsiveness and emotional reactivity during pubertal maturation: Implications for psychopathology. Development and Psychopathology. 2009; 21 (01):1–6. [ PubMed : 19144219 ]
  • Dallman MF, Pecoraro N, Akana SF, La Fleur SE, Gomez F, Houshyar H, Bell M, Bhatnagar S, Laugero KD, Manalo S. Chronic stress and obesity: A new view of “comfort food.” Proceedings of the National Academy of Sciences of the United States of America. 2003; 100 (20):11696–11701. [ PMC free article : PMC208820 ] [ PubMed : 12975524 ]
  • Danese A, Tan M. Childhood maltreatment and obesity: Systematic review and meta-analysis. Molecular Psychiatry. 2014; 19 (5):544–554. [ PubMed : 23689533 ]
  • Danese A, Pariante CM, Caspi A, Taylor A, Poulton R. Childhood maltreatment predicts adult inflammation in a life-course study. Proceedings of the National Academy of Sciences of the United States of America. 2007; 104 (4):1319–1324. [ PMC free article : PMC1783123 ] [ PubMed : 17229839 ]
  • de Bruyn E, Cillessen A, Wissink I. Associations of peer acceptance and perceived popularity with bullying and victimization in early adolescence. Journal of Early Adolescence. 2010; 30 (4):543–566.
  • Dick DM, Agrawal A, Keller MC, Adkins A, Aliev F, Monroe S, Hewitt JK, Kendler KS, Sher KJ. Candidate gene–environment interaction research: Reflections and recommendations. Perspectives on Psychological Science. 2015; 10 (1):37–59. [ PMC free article : PMC4302784 ] [ PubMed : 25620996 ]
  • Didden R, Scholte RHJ, Korzilius H, de Moor JMH, Vermeulen A, O'Reilly M, Lang R, Lancioni GE. Cyberbullying among students with intellectual and developmental disability in special education settings. Developmental Neurorehabilitation. 2009; 12 (3):146–151. [ PubMed : 19466622 ]
  • Dijkstra JK, Lindenberg S, Veenstra R. Beyond the class norm: Bullying behavior of popular adolescents and its relation to peer acceptance and rejection. Journal of Abnormal Child Psychology. 2008; 36 (8):1289–1299. [ PubMed : 18607717 ]
  • Dodge KA. Cognitive Perspectives on Children's Social and Behavioral Development: The Minnesota Symposia on Child Psychology, Volume 18. Perlmutter M, editor. New York: Psychology Press; 1986. pp. 77–125. (A social information processing model of social competence in children).
  • Dodge KA, Bates JE, Pettit GS. Mechanisms in the cycle of violence. Science. 1990; 250 (4988):1678–1683. [ PubMed : 2270481 ]
  • Duncan LE. Paying attention to all results, positive and negative. Journal of the American Academy of Child & Adolescent Psychiatry. 2013; 52 (5):462–465. [ PubMed : 23622847 ]
  • Duncan LE, Keller MC. A critical review of the first 10 years of candidate gene-by-environment interaction research in psychiatry. Perspectives. 2011; 168 (10):1041–1049. [ PMC free article : PMC3222234 ] [ PubMed : 21890791 ]
  • Duncan LE, Pollastri AR, Smoller JW. Mind the gap: Why many geneticists and psychological scientists have discrepant views about gene–environment interaction (G × E) research. American Psychologist. 2014; 69 (3):249–268. [ PMC free article : PMC7446184 ] [ PubMed : 24750075 ]
  • Eisenberger NI. The neural bases of social pain: Evidence for shared representations with physical pain. Psychosomatic Medicine. 2012; 74 (2):126–135. [ PMC free article : PMC3273616 ] [ PubMed : 22286852 ]
  • Eisenberger NI, Lieberman MD. Why rejection hurts: A common neural alarm system for physical and social pain. Trends in Cognitive Sciences. 2004; 8 (7):294–300. [ PubMed : 15242688 ]
  • Eisenberger NI, Lieberman MD, Williams KD. Does rejection hurt? An fMRI study of social exclusion. Science. 2003; 302 (5643):290–292. [ PubMed : 14551436 ]
  • Epel ES, Blackburn EH, Lin J, Dhabhar FS, Adler NE, Morrow JD, Cawthon RM. Accelerated telomere shortening in response to life stress. Proceedings of the National Academy of Sciences of the United States of America. 2004; 101 (49):17312–17315. [ PMC free article : PMC534658 ] [ PubMed : 15574496 ]
  • Espelage DL, Swearer SM, editors. Bullying in American Schools: A Social-Ecological Perspective on Prevention and Intervention. Mahwah, NJ: Lawrence Erlbaum Associates; 2004.
  • Espelage DL, Hong JS, Rao MA, Low S. Associations between peer victimization and academic performance. Theory Into Practice. 2013; 52 (4):233–240.
  • Espinoza G, Gonzales NA, Fuligni AJ. Daily school peer victimization experiences among Mexican-American adolescents: Associations with psychosocial, physical, and school adjustment. Journal of Youth and Adolescence. 2013; 42 (12):1775–1788. [ PMC free article : PMC3951444 ] [ PubMed : 23238764 ]
  • Euston DR, Gruber AJ, McNaughton BL. The role of medial prefrontal cortex in memory and decision making. Neuron. 2012; 76 (6):1057–1070. [ PMC free article : PMC3562704 ] [ PubMed : 23259943 ]
  • Evans GW, Kim P, Ting AH, Tesher HB, Shannis D. Cumulative risk, maternal responsiveness, and allostatic load among young adolescents. Developmental Psychology. 2007; 43 (2):341. [ PubMed : 17352543 ]
  • Faris R, Ennett S. Adolescent aggression: The role of peer group status motives, peer aggression, and group characteristics. Social Networks. 2012; 34 (4):371–378. [ PMC free article : PMC4138540 ] [ PubMed : 25152562 ]
  • Farmer TW, Estell DB, Bishop JL, O'Neal KK, Cairns BD. Rejected bullies or popular leaders? The social relations of aggressive subtypes of rural African American early adolescents. Developmental Psychology. 2003; 39 (6):992–1004. [ PubMed : 14584980 ]
  • Fein RA, Vossekuil B, Pollack WS, Borum R, Modzeleski W, Reddy M. Threat Assessment in Schools: A Guide to Managing Threatening Situations and Creating Safe School Climates. Washington, DC: U.S. Department of Education, Office of Elementary and Secondary Education, Safe and Drug-Free Schools Program and U.S. Secret Service, National Threat Assessment Center; 2002.
  • Feldman MA, Ojanen T, Gesten EL, Smith-Schrandt H, Brannick M, Totura CMW, Alexander L, Scanga D, Brown K. The effects of middle school bullying and victimization on adjustment through high school: Growth modeling of achievement, school attendance, and disciplinary trajectories. Psychology in the Schools. 2014; 51 (10):1046–1062.
  • Finkelhor D, Ormrod RK, Turner HA, Hamby SL. Measuring poly-victimization using the juvenile victimization questionnaire. Child Abuse & Neglect. 2005; 29 (11):1297–1312. [ PubMed : 16274741 ]
  • Finkelhor D, Ormrod RK, Turner HA. Poly-victimization: A neglected component in child victimization. Child Abuse & Neglect. 2007; 31 (1):7–26. [ PubMed : 17224181 ]
  • Finkelhor D, Ormrod RK, Turner HA. Lifetime assessment of poly-victimization in a national sample of children and youth. Child Abuse & Neglect. 2009; 33 (7):403–411. [ PubMed : 19589596 ]
  • Flannery DJ, Modzeleski W, Kretschmar JM. Violence and school shootings. Current Psychiatry Reports. 2013; 15 (1):1–7. [ PubMed : 23254623 ]
  • Flouri E, Buchanan A. The role of mother involvement and father involvement in adolescent bullying behavior. Journal of Interpersonal Violence. 2003; 18 (6):634–644.
  • Ford JD, Elhai JD, Connor DF, Frueh BC. Poly-victimization and risk of posttraumatic, depressive, and substance use disorders and involvement in delinquency in a national sample of adolescents. Journal of Adolescent Health. 2010; 46 (6):545–552. [ PubMed : 20472211 ]
  • Ford JD, Grasso DJ, Hawke J, Chapman JF. Poly-victimization among juvenile justice-involved youths. Child Abuse & Neglect. 2013; 37 (10):788–800. [ PubMed : 23428165 ]
  • Forero R, McLellan L, Rissel C, Bauman A. Bullying behaviour and psychosocial health among school students in New South Wales, Australia, Cross-Sectional Survey. BMJ. 1999; 319 (7206):344–348. [ PMC free article : PMC28186 ] [ PubMed : 10435953 ]
  • Ganzel BL, Kim P, Glover GH, Temple E. Resilience after 9/11: Multimodal neuroimaging evidence for stress-related change in the healthy adult brain. Neuroimage. 2008; 40 (2):788–795. [ PMC free article : PMC2405811 ] [ PubMed : 18234524 ]
  • Gastic B. School truancy and the disciplinary problems of bullying victims. Educational Review. 2008; 60 (4):391–404.
  • Gee DG, Gabard-Durnam L, Telzer EH, Humphreys KL, Goff B, Shapiro M, Flannery J, Lumian DS, Fareri DS, Caldera C. Maternal buffering of human amygdala-prefrontal circuitry during childhood but not during adolescence. Psychological Science. 2014 [ PMC free article : PMC4377225 ] [ PubMed : 25280904 ] [ CrossRef ]
  • Gibb SJ, Horwood LJ, Fergusson DM. Bullying victimization/perpetration in childhood and later adjustment: Findings from a 30-year longitudinal study. Journal of Aggression, Conflict and Peace Research. 2011; 3 (2):82–88.
  • Giedd JN, Blumenthal J, Jeffries NO, Castellanos FX, Liu H, Zijdenbos A, Paus T, Evans AC, Rapoport JL. Brain development during childhood and adolescence: A longitudinal MRI study. Nature Neuroscience. 1999; 2 (10):861–863. [ PubMed : 10491603 ]
  • Gini G. Associations between bullying behaviour, psychosomatic complaints, emotional and behavioural problems. Journal of Paediatrics and Child Health. 2008; 44 (9):492–497. [ PubMed : 17608653 ]
  • Gini G, Pozzoli T. Association between bullying and psychosomatic problems: A meta-analysis. Pediatrics. 2009; 123 (3):1059–1065. [ PubMed : 19255040 ]
  • Gini G, Pozzoli T. Bullied children and psychosomatic problems: A meta-analysis. Pediatrics. 2013; 132 (4):720–729. [ PubMed : 24043275 ]
  • Glew GM, Fan MY, Katon W, Rivara FP, Kernic MA. Bullying, psychosocial adjustment, and academic performance in elementary school. Archives of Pediatrics and Adolescent Medicine. 2005; 159 (11):1026–1031. [ PubMed : 16275791 ]
  • Glew GM, Fan MY, Katon W, Rivara FP. Bullying and school safety. Journal of Pediatrics. 2008; 152 (1):123–128. [ PMC free article : PMC3839286 ] [ PubMed : 18154913 ]
  • Graham S. Peer victimization in school: Exploring the ethnic context. Current Directions in Psychological Science. 2006; 15 (6):317–321.
  • Graham S, Bellmore AD. Peer victimization and mental health during early adolescence. Theory into Practice. 2007; 46 (2):138–146.
  • Graham S, Juvonen J. Self-blame and peer victimization in middle school: An attributional analysis. Developmental Psychology. 1998; 34 (3):587–599. [ PubMed : 9597367 ]
  • Graham S, Bellmore AD, Mize J. Peer victimization, aggression, and their co-occurrence in middle school: Pathways to adjustment problems. Journal of Abnormal Child Psychology. 2006; 34 (3):349–364. [ PubMed : 16648999 ]
  • Graham S, Bellmore A, Nishina A, Juvonen J. “It must be me”: Ethnic diversity and attributions for peer victimization in middle school. Journal of Youth and Adolescence. 2009; 38 (4):487–499. [ PubMed : 19636723 ]
  • Greenberg DB. Somatization: Epidemiology, Pathogenesis, Clinical Features, Medical Evaluation, and Diagnosis. 2016. [June 2016]. http://www ​.uptodate.com ​/contents/somatizationtreatment-and-prognosis?source ​=see_link .
  • Gross JJ. Emotion regulation in adulthood: Timing is everything. Current Directions in Psychological Science. 2001; 10 (6):214–219.
  • Hager AD, Leadbeater BJ. The longitudinal effects of peer victimization on physical health from adolescence to young adulthood. Journal of Adolescent Health. 2016; 58 (3):330–336. [ PubMed : 26704181 ]
  • Hanish LD, Eisenberg N, Fabes RA, Spinrad TL, Ryan P, Schmidt S. The expression and regulation of negative emotions: Risk factors for young children's peer victimization. Development and Psychopathology. 2004; 16 (02):335–353. [ PubMed : 15487599 ]
  • Hanson JL, Nacewicz BM, Sutterer MJ, Cayo AA, Schaefer SM, Rudolph KD, Shirtcliff EA, Pollak SD, Davidson RJ. Behavioral problems after early life stress: Contributions of the hippocampus and amygdala. Biological Psychiatry. 2015; 77 (4):314–323. [ PMC free article : PMC4241384 ] [ PubMed : 24993057 ]
  • Harris JR. Where is the child's environment? A group socialization theory of development. Psychological Review. 1995; 102 (3):458–489.
  • Harvey AG, Tang NK. (Mis) perception of sleep in insomnia: A puzzle and a resolution. Psychological Bulletin. 2012; 138 (1):77–101. [ PMC free article : PMC3277880 ] [ PubMed : 21967449 ]
  • Hawker DS, Boulton MJ. Twenty years' research on peer victimization and psychosocial maladjustment: A meta-analytic review of cross-sectional studies. Journal of Child Psychology and Psychiatry. 2000; 41 (4):441–455. [ PubMed : 10836674 ]
  • Heim C, Owens MJ, Plotsky PM, Nemeroff CB. Persistent changes in corticotropin-releasing factor systems due to early life stress: Relationship to the pathophysiology of major depression and post-traumatic stress disorder. Psychopharmacology Bulletin. 1997; 33 (2):185–192. [ PubMed : 9230630 ]
  • Hennessy MB, Kaiser S, Sachser N. Social buffering of the stress response: Diversity, mechanisms, and functions. Frontiers in Neuroendocrinology. 2009; 30 (4):470–482. [ PubMed : 19545584 ]
  • Hennessy MB, Schiml PA, Willen R, Watanasriyakul W, Johnson J, Garrett T. Selective social buffering of behavioral and endocrine responses and Fos induction in the prelimbic cortex of infants exposed to a novel environment. Developmental Psychobiology. 2015; 57 (1):50–62. [ PubMed : 25355379 ]
  • Herts KL, McLaughlin KA, Hatzenbuehler ML. Emotion dysregulation as a mechanism linking stress exposure to adolescent aggressive behavior. Journal of Abnormal Child Psychology. 2012; 40 (7):1111–1122. [ PMC free article : PMC3448707 ] [ PubMed : 22466516 ]
  • Holt MK, Vivolo-Kantor AM, Polanin JR, Holland KM, DeGue S, Matjasko JL, Wolfe M, Reid G. Bullying and suicidal ideation and behaviors: A meta-analysis. Pediatrics. 2015; 135 (2):e496–e509. [ PMC free article : PMC4702491 ] [ PubMed : 25560447 ]
  • Hostinar CE, Sullivan RM, Gunnar MR. Psychobiological mechanisms underlying the social buffering of the hypothalamic–pituitary–adrenocortical axis: A review of animal models and human studies across development. Psychological Bulletin. 2014; 140 (1):256–282. [ PMC free article : PMC3844011 ] [ PubMed : 23607429 ]
  • Hostinar CE, Johnson AE, Gunnar MR. Parent support is less effective in buffering cortisol stress reactivity for adolescents compared to children. Developmental Science. 2015; 18 (2):281–297. [ PMC free article : PMC4270957 ] [ PubMed : 24942038 ]
  • Huesmann LR, Guerra NG. Children's normative beliefs about aggression and aggressive behavior. Journal of Personality and Social Psychology. 1997; 72 (2):408–419. [ PubMed : 9107008 ]
  • Hunter SC, Durkin K, Boyle JM, Booth JN, Rasmussen S. Adolescent bullying and sleep difficulties. Europe's Journal of Psychology. 2014; 10 (4):740–755.
  • Institute of Medicine and National Research Council. Building Capacity to Reduce Bullying: Workshop Summary. Washington, DC: The National Academies Press; 2014a. [ PubMed : 25232636 ]
  • Institute of Medicine and National Research Council. New Directions in Child Abuse and Neglect Research. Washington, DC: The National Academies Press; 2014b. [ PubMed : 24757747 ]
  • Inzlicht M, McKay L, Aronson J. Stigma as ego depletion: How being the target of prejudice affects self-control. Psychological Science. 2006; 17 (3):262–269. [ PubMed : 16507068 ]
  • Iyer PA, Dougall AL, Jensen-Campbell LA. Are some adolescents differentially susceptible to the influence of bullying on depression? Journal of Research in Personality. 2013; 47 (4):272–281.
  • Janoff-Bulman R. Characterological versus behavioral self-blame: Inquiries into depression and rape. Journal of Personality and Social Psychology. 1979; 37 (10):1798–1809. [ PubMed : 512837 ]
  • Jovanovic T, Smith A, Gamwell K, Nylocks M, Norrholm SD, Ressler KJ, Bradley B. Psychophysiological biomarkers of anxiety in children at high risk for trauma exposure. Biological Psychiatry. 2013; 73 (9):17S–17S.
  • Judd LL, Schettler PJ, Brown ES, Wolkowitz OM, Sternberg EM, Bender BG, Bulloch K, Cidlowski JA, de Kloet ER, Fardet L. Adverse consequences of glucocorticoid medication: Psychological, cognitive, and behavioral effects. American Journal of Psychiatry. 2014; 171 (10):1045–1051. [ PubMed : 25272344 ]
  • Juvonen J, Graham S. Bullying in schools: The power of bullies and the plight of victims. Annual Review of Psychology. 2014; 65 (1):159–185. [ PubMed : 23937767 ]
  • Juvonen J, Nishina A, Graham S. Peer harassment, psychological adjustment, and school functioning in early adolescence. Journal of Educational Psychology. 2000; 92 (2):349–359.
  • Juvonen J, Graham S, Schuster MA. Bullying among young adolescents: The strong, the weak, and the troubled. Pediatrics. 2003; 112 (6):1231–1237. [ PubMed : 14654590 ]
  • Juvonen J, Wang Y, Espinoza G. Bullying experiences and compromised academic performance across middle school grades. Journal of Early Adolescence. 2011; 31 (1):152–173.
  • Kalmakis KA, Chandler GE. Health consequences of adverse childhood experiences: A systematic review. Journal of the American Association of Nurse Practitioners. 2015; 27 (8):457–465. [ PubMed : 25755161 ]
  • Karg K, Burmeister M, Shedden K, Sen S. The serotonin transporter promoter variant (5-HTTLPR), stress, and depression meta-analysis revisited: Evidence of genetic moderation. Archives of General Psychiatry. 2011; 68 (5):444–454. [ PMC free article : PMC3740203 ] [ PubMed : 21199959 ]
  • Kidger J, Heron J, Leon DA, Tilling K, Lewis G, Gunnell D. Self-reported school experience as a predictor of self-harm during adolescence: A prospective cohort study in the south west of England (ALSPAC). Journal of Affective Disorders. 2015; 173 :163–169. [ PMC free article : PMC4286629 ] [ PubMed : 25462412 ]
  • Kiecolt-Glaser JK, Gouin JP, Weng NP, Malarkey WB, Beversdorf DQ, Glaser R. Childhood adversity heightens the impact of later-life caregiving stress on telomere length and inflammation. Psychosomatic Medicine. 2011; 73 (1):16–22. [ PMC free article : PMC3051180 ] [ PubMed : 21148804 ]
  • Kim YS, Leventhal B. Bullying and suicide. A review. International Journal of Adolescent Medicine and Health. 2008; 20 (2):133–154. [ PubMed : 18714552 ]
  • Kim JH, Richardson R. New findings on extinction of conditioned fear early in development: Theoretical and clinical implications. Biological Psychiatry. 2010; 67 (4):297–303. [ PubMed : 19846065 ]
  • Kim YS, Leventhal BL, Koh YJ, Hubbard A, Boyce WT. School bullying and youth violence: Causes or consequences of psychopathologic behavior? Archives of General Psychiatry. 2006; 63 (9):1035–1041. [ PubMed : 16953006 ]
  • Kimmel MS, Mahler M. Adolescent masculinity, homophobia, and violence: Random school shootings, 1982-2001. American Behavioral Scientist. 2003; 46 (10):1439–1458.
  • Klein J. The Bully Society: School Shootings and the Crisis of Bullying in America's Schools. New York: New York University Press; 2012.
  • Kliewer W. Violence exposure and cortisol responses in urban youth. International Journal of Behavioral Medicine. 2006; 13 (2):109–120. [ PubMed : 16712428 ]
  • Kliewer W, Dibble AE, Goodman KL, Sullivan TN. Physiological correlates of peer victimization and aggression in African American urban adolescents. Development and Psychopathology. 2012; 24 (2):637–650. [ PMC free article : PMC5828867 ] [ PubMed : 22559136 ]
  • Klomek AB, Marrocco F, Kleinman M, Schonfeld IS, Gould MS. Bullying, depression, and suicidality in adolescents. Journal of the American Academy of Child & Adolescent Psychiatry. 2007; 46 (1):40–49. [ PubMed : 17195728 ]
  • Klomek AB, Sourander A, Niemelä S, Kumpulainen K, Piha J, Tamminen T, Almqvist F, Gould MS. Childhood bullying behaviors as a risk for suicide attempts and completed suicides: A population-based birth cohort study. Journal of the American Academy of Child & Adolescent Psychiatry. 2009; 48 (3):254–261. [ PubMed : 19169159 ]
  • Klomek AB, Sourander A, Gould M. The association of suicide and bullying in childhood to young adulthood: A review of cross-sectional and longitudinal research findings. Canadian Journal of Psychiatry. 2010; 55 (5):282–288. [ PubMed : 20482954 ]
  • Klomek AB, Sourander A, Elonheimo H. Bullying by peers in childhood and effects on psychopathology, suicidality, and criminality in adulthood. The Lancet Psychiatry. 2015; 2 (10):930–941. [ PubMed : 26462227 ]
  • Knack JM, Gomez HL, Jensen-Campbell LA. Social Pain: Neuropsychological and Health Implications of Loss and Exclusion. MacDonald G, Jensen-Campbell LA, editors. Washington, DC: American Psychological Association; 2011a. pp. 215–236. (Bullying and its long-term health implications).
  • Knack JM, Jensen-Campbell LA, Baum A. Worse than sticks and stones? Bullying is associated with altered HPA axis functioning and poorer health. Brain and Cognition. 2011b; 77 (2):183–190. [ PubMed : 21839567 ]
  • Knack J, Vaillancourt T, Hutcherson A. Psychology of Victimization. Hutcherson AN, editor. New York: Nova Science; 2012a. [June 2016]. pp. 205–218. (Evidence of altered cortisol levels across child maltreatment, intimate partner abuse, and peer victimization). https://www ​.novapublishers ​.com/catalog/product_info ​.php?products_id=27225 .
  • Knack JM, Tsar V, Vaillancourt T, Hymel S, McDougall P. What protects rejected adolescents from also being bullied by their peers? The moderating role of peer-valued characteristics. Journal of Research on Adolescence. 2012b; 22 (3):467–479.
  • Kochel KP, Ladd GW, Rudolph KD. Longitudinal associations among youth depressive symptoms, peer victimization, and low peer acceptance: An interpersonal process perspective. Child Development. 2012; 83 (2):637–650. [ PMC free article : PMC3305833 ] [ PubMed : 22313098 ]
  • Kochenderfer BJ, Ladd GW. Peer victimization: Cause or consequence of school maladjustment? Child Development. 1996; 67 (4):1305–1317. [ PubMed : 8890485 ]
  • Kowalski RM, Limber SP. Psychological, physical, and academic correlates of cyberbullying and traditional bullying. Journal of Adolescent Health. 2013; 53 (1):S13–S20. [ PubMed : 23790195 ]
  • Kretschmer T, Dijkstra JK, Ormel J, Verhulst FC, Veenstra R. Dopamine receptor D4 gene moderates the effect of positive and negative peer experiences on later delinquency: The Tracking Adolescents' Individual Lives Survey study. Development and Psychopathology. 2013; 25 (4 pt. 1):1107–1117. [ PubMed : 24229552 ]
  • Kross E, Berman MG, Mischel W, Smith EE, Wager TD. Social rejection shares somatosensory representations with physical pain. Proceedings of the National Academy of Sciences of the United States of America. 2011; 108 (15):6270–6275. [ PMC free article : PMC3076808 ] [ PubMed : 21444827 ]
  • Kumpulainen K, Räsänen E, Puura K. Psychiatric disorders and the use of mental health services among children involved in bullying. Aggressive Behavior. 2001; 27 (2):102–110.
  • Ladd GW, Kochenderfer-Ladd B. Identifying victims of peer aggression from early to middle childhood: Analysis of cross-informant data for concordance, estimation of relational adjustment, prevalence of victimization, and characteristics of identified victims. Psychological Assessment. 2002; 14 (1):74–96. [ PubMed : 11911051 ]
  • Lake A, Chan M. Putting science into practice for early child development. The Lancet. 2015; 385 (9980):1816–1817. [ PubMed : 25245180 ]
  • Langman P. Rampage school shooters: A typology. Aggression and Violent Behavior. 2009; 14 (1):79–86.
  • Langman P. School Shooters: Understanding High School, College, and Adult Perpetrators. Lanham, MD: Rowman & Littlefield; 2015.
  • Leary M, Kowalski R, Smith L, Phillips S. Teasing, rejection, and violence: Case studies of the school shootings. Aggressive Behavior. 2003; 29 (3):202–214.
  • Lee HS, Lee JE, Lee KU, Kim YH. Neural changes associated with emotion processing in children experiencing peer rejection: A functional MRI study. Journal of Korean Medical Science. 2014; 29 (9):1293–1300. [ PMC free article : PMC4168185 ] [ PubMed : 25246750 ]
  • Lereya ST, Copeland WE, Costello EJ, Wolke D. Adult mental health consequences of peer bullying and maltreatment in childhood: Two cohorts in two countries. The Lancet Psychiatry. 2015; 2 (6):524–531. [ PMC free article : PMC4580734 ] [ PubMed : 26360448 ]
  • Lim L, Radua J, Rubia K. Gray matter abnormalities in childhood maltreatment: A voxel-wise meta-analysis. American Journal of Psychiatry. 2014; 171 (8):854–863. [ PubMed : 24781447 ]
  • Lim L, Hart H, Mehta MA, Simmons A, Mirza K, Rubia K. Neural correlates of error processing in young people with a history of severe childhood abuse: An fMRI study. American Journal of Psychiatry. 2015; 172 (9):892–900. [ PubMed : 25882324 ]
  • Liston C, McEwen B, Casey B. Psychosocial stress reversibly disrupts prefrontal processing and attentional control. Proceedings of the National Academy of Sciences of the United States of America. 2009; 106 (3):912–917. [ PMC free article : PMC2621252 ] [ PubMed : 19139412 ]
  • Lodge J, Frydenberg E. The role of peer bystanders in school bullying: Positive steps toward promoting peaceful schools. Theory Into Practice. 2005; 44 (4):329–336.
  • Lupien SJ, Fiocco A, Wan N, Maheu F, Lord C, Schramek T, Tu MT. Stress hormones and human memory function across the lifespan. Psychoneuroendocrinology. 2005; 30 (3):225–242. [ PubMed : 15511597 ]
  • Madfis E. The Risk of School Rampage: Assessing and Preventing Threats of School Violence. New York: Polgrave MacMillan; 2014.
  • Mahady Wilton MM, Craig WM, Pepler DJ. Emotional regulation and display in classroom victims of bullying: Characteristic expressions of affect, coping styles, and relevant contextual factors. Social Development. 2000; 9 (2):227–245.
  • Márquez C, Poirier GL, Cordero MI, Larsen MH, Groner A, Marquis J, Magistretti PJ, Trono D, Sandi C. Peripuberty stress leads to abnormal aggression, altered amygdala and orbitofrontal reactivity and increased prefrontal MAOA gene expression. Translational Psychiatry. 2013; 3 (1):1–12. [ PMC free article : PMC3566724 ] [ PubMed : 23321813 ]
  • McCormick CM, Mathews IZ. HPA function in adolescence: Role of sex hormones in its regulation and the enduring consequences of exposure to stressors. Pharmacology Biochemistry and Behavior. 2007; 86 (2):220–233. [ PubMed : 16901532 ]
  • McDermott R, Tingley D, Cowden J, Frazzetto G, Johnson DD. Monoamine oxidase A gene (MAOA) predicts behavioral aggression following provocation. Proceedings of the National Academy of Sciences of the United States of America. 2009; 106 (7):2118–2123. [ PMC free article : PMC2650118 ] [ PubMed : 19168625 ]
  • McDougall P, Vaillancourt T. Long-term adult outcomes of peer victimization in childhood and adolescence: Pathways to adjustment and maladjustment. American Psychologist. 2015; 70 (4):300–310. [ PubMed : 25961311 ]
  • McEwen BS. Synaptic Stress and Pathogenesis of Neuropsychiatric Disorders. Popoli M, Diamond D, Sanacora G, editors. New York: Springer; 2014. pp. 1–18. (The brain on stress: The good and the bad).
  • McEwen BS, Karatsoreos IN. Sleep deprivation and circadian disruption: Stress, allostasis, and allostatic load. Sleep Medicine Clinics. 2015; 10 (1):1–10. [ PMC free article : PMC8935364 ] [ PubMed : 26055668 ]
  • McEwen BS, McEwen CA. Emerging Trends in the Social and Behavioral Sciences: An Interdisciplinary, Searchable, and Linkable Resource. Scott RA, Kosslyn SM, Pinkerton N, editors. New York: J. Wiley; 2015. pp. 1–15. (Social, psychological, and physiological reactions to stress).
  • McEwen BS, Morrison JH. The brain on stress: Vulnerability and plasticity of the prefrontal cortext over the life course. Neuron. 2013; 79 (1):16–29. [ PMC free article : PMC3753223 ] [ PubMed : 23849196 ]
  • McEwen BS, Gray JD, Nasca C. Recognizing resilience: Learning from the effects of stress on the brain. Neurobiology of Stress. 2015; 1 :1–11. [ PMC free article : PMC4260341 ] [ PubMed : 25506601 ]
  • McGaugh JL. Consolidating memories. Annual Review of Psychology. 2015; 66 :1–24. [ PubMed : 25559113 ]
  • McGee TR, Scott JG, McGrath JJ, Williams GM, O'Callaghan M, Bor W, Najman JM. Young adult problem behaviour outcomes of adolescent bullying. Journal of Aggression, Conflict and Peace Research. 2011; 3 (2):110–114.
  • McGowan PO, Sasaki A, D'Alessio AC, Dymov S, Labonté B, Szyf M, Turecki G, Meaney MJ. Epigenetic regulation of the glucocorticoid receptor in human brain associates with childhood abuse. Nature Neuroscience. 2009; 12 (3):342–348. [ PMC free article : PMC2944040 ] [ PubMed : 19234457 ]
  • McGowan PO, Suderman M, Sasaki A, Huang T, Hallett M, Meaney MJ, Szyf M. Broad epigenetic signature of maternal care in the brain of adult rats. PLoS One. 2011; 6 (2) [August 2016]; http://journals ​.plos ​.org/plosone/article?id=10 ​.1371/journal.pone.0014739 . [ PMC free article : PMC3046141 ] [ PubMed : 21386994 ]
  • McLaughlin KA, Hatzenbuehler ML, Hilt LM. Emotion dysregulation as a mechanism linking peer victimization to internalizing symptoms in adolescents. Journal of Consulting and Clinical Psychology. 2009; 77 (5):894–904. [ PMC free article : PMC2778003 ] [ PubMed : 19803569 ]
  • Milaid MR, Quirk GJ. Fear extinction as a model for translational neuroscience: Ten years of progress. Annual Review of Psychology. 2012; 63 :129–151. [ PMC free article : PMC4942586 ] [ PubMed : 22129456 ]
  • Miller GE, Chen E, Zhou ES. If it goes up, must it come down? Chronic stress and the hypothalamic-pituitary-adrenocortical axis in humans. Psychological Bulletin. 2007; 133 (1):25–45. [ PubMed : 17201569 ]
  • Miller GE, Chen E. Harsh family climate in early life presages the emergence of a proinflammatory phenotype in adolescence. Psychological Science. 2010; 21 (6):848–856. [ PMC free article : PMC3207635 ] [ PubMed : 20431047 ]
  • Miller-Graff LE, Cater ÅK, Howell KH, Graham-Bermann SA. Victimization in childhood: General and specific associations with physical health problems in young adulthood. Journal of Psychosomatic Research. 2015; 70 (4):269–271. [ PubMed : 26208402 ]
  • Moffitt TE. Teen-aged mothers in contemporary Britain. Journal of Child Psychology and Psychiatry. 2002; 43 (6):727–742. [ PubMed : 12236608 ]
  • Montoya ER, Terburg D, Bos PA, Van Honk J. Testosterone, cortisol, and serotonin as key regulators of social aggression: A review and theoretical perspective. Motivation and Emotion. 2012; 36 (1):65–73. [ PMC free article : PMC3294220 ] [ PubMed : 22448079 ]
  • Moriceau S, Sullivan RM. Maternal presence serves as a switch between learning fear and attraction in infancy. Nature Neuroscience. 2006; 9 (8):1004–1006. [ PMC free article : PMC1560090 ] [ PubMed : 16829957 ]
  • Mulvey E, Cauffman E. The inherent limits of predicting school violence. American Psychologist. 2001; 56 (10):797–802. [ PubMed : 11675986 ]
  • Musher-Eizenman DR, Boxer P, Danner S, Dubow EF, Goldstein SE, Heretick DML. Social-cognitive mediators of the relation of environmental and emotion regulation factors to children's aggression. Aggressive Behavior. 2004; 30 (5):389–408.
  • Nair HP, Gonzalez-Lima F. Extinction of behavior in infant rats: Development of functional coupling between septal hippocampal and vental tegmental regions. The Journal of Neuroscience. 1999; 19 (19):8646–8655. [ PMC free article : PMC6783035 ] [ PubMed : 10493765 ]
  • Nakamoto J, Schwartz D. Is peer victimization associated with academic achievement? A meta-analytic review. Social Development. 2010; 19 (2):221–242.
  • Nansel TR, Overpeck M, Pilla RS, Ruan WJ, Simons-Morton B, Scheidt P. Bullying behaviors among U.S. youth: Prevalence and association with psychosocial adjustment. Journal of the American Medical Association. 2001; 285 (16):2094–2100. [ PMC free article : PMC2435211 ] [ PubMed : 11311098 ]
  • Nansel TR, Haynie DL, Simonsmorton BG. The association of bullying and victimization with middle school adjustment. Journal of Applied School Psychology. 2003; 19 (2):45–61.
  • Nansel TR, Craig W, Overpeck MD, Saluja G, Ruan WJ. Cross-national consistency in the relationship between bullying behaviors and psychosocial adjustment. Archives of Pediatrics and Adolescent Medicine. 2004; 158 (8):730–736. [ PMC free article : PMC2556236 ] [ PubMed : 15289243 ]
  • National Research Council and Institute of Medicine; Division of Behavioral and Social Sciences and Education. Deadly Lessons: Understanding Lethal School Violence. Moore MH, Petrie CV, Braga AA, McLaughlin BL, editors. Washington, DC: The National Academies Press; 2003. (Case Studies of School Violence Committee).
  • Neary A, Joseph S. Peer victimization and its relationship to self-concept and depression among schoolgirls. Personality and Individual Differences. 1994; 16 (1):183–186.
  • Newman KS, Fox C, Harding D, Mehta J, Roth W. Rampage: The Social Roots of School Shootings. New York: Basic Books; 2004.
  • Newman ML. Here we go again: Bullying history and cardiovascular responses to social exclusion. Physiology & Behavior. 2014; 133 :76–80. [ PubMed : 24858188 ]
  • Nishina A, Juvonen J. Daily reports of witnessing and experiencing peer harassment in middle school. Child Development. 2005; 76 (2):435–450. [ PubMed : 15784092 ]
  • Niv S, Tuvblad C, Raine A, Baker LA. Aggression and rule-breaking: Heritability and stability of antisocial behavior problems in childhood and adolescence. Journal of Criminal Justice. 2013; 41 (5):285–291. [ PMC free article : PMC3856338 ] [ PubMed : 24347737 ]
  • Nixon C. Current perspectives: The impact of cyberbullying on adolescent health. Adolescent Health, Medicine and Therapeutics. 2014:143–158. [ PMC free article : PMC4126576 ] [ PubMed : 25177157 ]
  • O'Brennan LM, Bradshaw CP, Sawyer AL. Examining developmental differences in the social-emotional problems among frequent bullies, victims, and bully/victims. Psychology in the Schools. 2009; 46 (2):100–115.
  • Obradovic J, Bush NR, Stamperdahl J, Adler NE, Boyce WT. Biological sensitivity to context: The interactive effects of stress reactivity and family adversity on socioemotional behavior and school readiness. Child Development. 2010; 81 (1):270–289. [ PMC free article : PMC2846098 ] [ PubMed : 20331667 ]
  • Olweus D. Bullying at School. What We Know and What We Can Do. Oxford, UK: Blackwell; 1993a.
  • Olweus D. Social Withdrawal, Inhibition, and Shyness in Childhood. Rubin KH, Asendorpf JB, editors. New York: Psychology Press; 1993b. pp. 315–341. (Victimization by peers: Antecedents and long-term outcomes).
  • Ostrov JM, Kamper KE. Future directions for research on the development of relational and physical peer victimization. Journal of Clinical Child & Adolescent Psychology. 2015; 44 (3):509–519. [ PubMed : 25751392 ]
  • O'Toole ME. The School Shooter: A Threat Assessment Perspective. Quantico, VA: US Department of Justice, Federal Bureau of Investigation; 2000.
  • O'Toole ME, Folino PJ, Garbarino J, Gorelick SM, Häkkänen-Nyholm H, Meloy JR, Samenow SE, Nishimura YS. Why do young males attack schools? Seven discipline leaders share their perspectives. Violence and Gender. 2014; 1 (1):13–18.
  • Ouellet-Morin I, Odgers CL, Danese A, Bowes L, Shakoor S, Papadopoulos AS, Caspi A, Moffitt TE, Arseneault L. Blunted cortisol responses to stress signal social and behavioral problems among maltreated/bullied 12-year-old children. Biological Psychiatry. 2011; 70 (11):1016–1023. [ PMC free article : PMC3816750 ] [ PubMed : 21839988 ]
  • Ouellet-Morin I, Wong C, Danese A, Pariante C, Papadopoulos A, Mill J, Arseneault L. Increased serotonin transporter gene (SERT) DNA methylation is associated with bullying victimization and blunted cortisol response to stress in childhood: A longitudinal study of discordant monozygotic twins. Psychological Medicine. 2013; 43 (09):1813–1823. [ PMC free article : PMC4231789 ] [ PubMed : 23217646 ]
  • Patchin JW. Bullies move beyond the schoolyard: A preliminary look at cyberbullying. Youth Violence and Juvenile Justice. 2006; 4 (2):148–169.
  • Patton DU, Hong JS, Patel S, Kral MJ. A systematic review of research strategies used in qualitative studies on school bullying and victimization. Trauma, Violence, & Abuse. 2015:1–14. [ PubMed : 26092753 ] [ CrossRef ]
  • Pattwell SS, Duhoux S, Hartley CA, Johnson DC, Jing D, Elliott MD, Ruberry EJ, Powers A, Mehta N, Yand RR, Soliman F, Glatt CE, Casey BJ, Ninan I, Lee FS. Altered fear learning across development in both mouse and human. Proceedings of the National Academy of Sciences of the United States of America. 2012; 109 (40):16318–16323. [ PMC free article : PMC3479553 ] [ PubMed : 22988092 ]
  • Pattwell SS, Lee FS, Casey BJ. Fear learning and memory across adolescent development: Hormones and behavior special issue: Puberty and adolescence. Hormones and Behavior. 2013; 64 (2):380–389. [ PMC free article : PMC3761221 ] [ PubMed : 23998679 ]
  • Peeters M, Cillessen AH, Scholte RH. Clueless or powerful? Identifying subtypes of bullies in adolescence. Journal of Youth and Adolescence. 2010; 39 (9):1041–1052. [ PubMed : 20625880 ]
  • Perren S, Ettekal I, Ladd G. The impact of peer victimization on later maladjustment: Mediating and moderating effects of hostile and self-blaming attributions. Journal of Child Psychology and Psychiatry. 2012; 54 (1):46–55. [ PMC free article : PMC3527635 ] [ PubMed : 23057732 ]
  • Perry R, Sullivan RM. Neurobiology of attachment to an abusive caregiver: Short-term benefits and long-term costs. Developmental Psychobiology. 2014; 56 (8):1626–1634. [ PMC free article : PMC4209208 ] [ PubMed : 24771610 ]
  • Plomin R, DeFries JC, Loehlin JC. Genotype-environment interaction and correlation in the analysis of human behavior. Psychological Bulletin. 1977; 84 (2):309–322. [ PubMed : 557211 ]
  • Polanin JR, Espelage DL, Pigott TD. A meta-analysis of school-based bullying prevention programs' effects on bystander intervention behavior. School Psychology Review. 2012; 41 (1):47–65.
  • Prinstein MJ, Cheah CSL, Guyer AE. Peer victimization, cue interpretation, and internalizing symptoms: Preliminary concurrent and longitudinal findings for children and adolescents. Journal of Clinical Child & Adolescent Psychology. 2005; 34 (1):11–24. [ PubMed : 15677277 ]
  • Radley JJ, Rocher AB, Miller M, Janssen WG, Liston C, Hof PR, McEwen BS, Morrison JH. Repeated stress induces dendritic spine loss in the rat medial prefrontal cortex. Cerebral Cortex. 2006; 16 (3):313–320. [ PubMed : 15901656 ]
  • Radliff KM, Wheaton JE, Robinson K, Morris J. Illuminating the relationship between bullying and substance use among middle and high school youth. Addictive Behaviors. 2012; 37 (4):569–572. [ PubMed : 22277772 ]
  • Rau V, Fanselow MS. Exposure to a stressor produces a long lasting enhancement of fear learning in rats: Original research report. Stress. 2009; 12 (2):125–133. [ PubMed : 18609302 ]
  • Reijntjes A, Kamphuis JH, Prinzie P, Telch MJ. Peer victimization and internalizing problems in children: A meta-analysis of longitudinal studies. Child Abuse & Neglect. 2010; 34 (4):244–252. [ PubMed : 20304490 ]
  • Reijntjes A, Kamphuis JH, Prinzie P, Boelen PA, Van der Schoot M, Telch MJ. Prospective linkages between peer victimization and externalizing problems in children: A meta-analysis. Aggressive Behavior. 2011; 37 (3):215–222. [ PubMed : 21433031 ]
  • Repetti RL, Taylor SE, Seeman TE. Risky families: Family social environments and the mental and physical health of offspring. Psychological Bulletin. 2002; 128 (2):330–366. [ PubMed : 11931522 ]
  • Retz W, Retz-Junginger P, Supprian T, Thome J, Rösler M. Association of serotonin transporter promoter gene polymorphism with violence: Relation with personality disorders, impulsivity, and childhood adhd psychopathology. Behavioral Sciences & the Law. 2004; 22 (3):415–425. [ PubMed : 15211560 ]
  • Reuter-Rice K. Male adolescent bullying and the school shooter. Journal of School Nursing. 2008; 24 (6):350–359. [ PubMed : 19114465 ]
  • Richter-Levin G, Horovitz O, Tsoory MM. Future Directions in Post-Traumatic Stress Disorder: Prevention Diagnosis, and Treatment. Safir MP, Wallach HS, Rizzo A, editors. New York: Springer; 2015. (The early adolescent of “juvenile stress” translational animal model of posttraumatic stress disorder).
  • Rigby K, Slee PT. Dimensions of interpersonal relation among Australian children and implications for psychological well-being. Journal of Social Psychology. 1993; 133 (1):33–42. [ PubMed : 8464217 ]
  • Rivers I, Noret N. Potential suicide ideation and its association with observing bullying at school. Journal of Adolescent Health. 2013; 53 (1):S32–S36. [ PubMed : 23790198 ]
  • Rivers I, Poteat VP, Noret N, Ashurst N. Observing bullying at school: The mental health implications of witness status. School Psychology Quarterly. 2009; 24 (4):211–223.
  • Robertson KD. DNA methylation and human disease. Nature Reviews: Genetics. 2005; 6 (8):597–610. [ PubMed : 16136652 ]
  • Rocque M. Exploring school rampage shootings: Research, theory, and policy. Social Science Journal. 2012; 49 (3):304–313.
  • Rodkin PC. Bullying in American Schools: A Social-Ecological Perspective on Prevention and Intervention. Espelage DL, Swearer SM, editors. Mahwah, NJ: Lawrence Erlbaum Associates; 2004. pp. 87–106. (Peer ecologies of aggression and bullying).
  • Rodkin PC, Espelage DL, Hanish LD. A relational framework for understanding bullying: Developmental antecedents and outcomes. American Psychologist. 2015; 70 (4):311–321. [ PubMed : 25961312 ]
  • Romeo RD. Pubertal maturation and programming of hypothalamic–pituitary–adrenal reactivity. Frontiers in Neuroendocrinology. 2010; 31 (2):232–240. [ PubMed : 20193707 ]
  • Romeo RD. Perspectives on stress resilience and adolescent neurobehavioral function. Neurobiology of Stress. 2015; 1 :128–133. [ PMC free article : PMC4721430 ] [ PubMed : 27589663 ]
  • Roth TL. How traumatic experiences leave their signature on the genome: An overview of epigenetic pathways in PTSD. Frontiers in Psychiatry. 2014; 5 (93):1–2. [ PMC free article : PMC4116797 ] [ PubMed : 25132824 ]
  • Roth TL, Sweatt JD. Epigenetic marking of the BDNF gene by early-life adverse experiences. Hormones and Behavior. 2011; 59 (3):315–320. [ PMC free article : PMC2948595 ] [ PubMed : 20483357 ]
  • Rudolph KD, Troop-Gordon W, Flynn M. Relational victimization predicts children's social-cognitive and self-regulatory responses in a challenging peer context. Developmental Psychology. 2009; 45 (5):1444–1454. [ PMC free article : PMC2780469 ] [ PubMed : 19702404 ]
  • Rudolph KD, Miernicki ME, Troop-Gordon W, Davis MM, Telzer EH. Adding insult to injury: Neural sensitivity to social exclusion is associated with internalizing symptoms in chronically peer-victimized girls. Social Cognitive and Affective Neuroscience. 2016 [ PMC free article : PMC4847705 ] [ PubMed : 26892162 ] [ CrossRef ]
  • Rueger SY, Jenkins LN. Effects of peer victimization on psychological and academic adjustment in early adolescence. School Psychology Quarterly. 2014; 29 (1):77–88. [ PubMed : 24015982 ]
  • Rueger SY, Malecki CK, Demaray MK. Stability of peer victimization in early adolescence: Effects of timing and duration. Journal of School Psychology. 2011; 49 (4):443–464. [ PubMed : 21724000 ]
  • Salmivalli C. Bullying and the peer group: A review. Aggression and Violent Behavior. 2010; 15 (2):112–120.
  • Salmivalli C, Lagerspetz K, Björkqvist K, Österman K, Kaukiainen A. Bullying as a group process: Participant roles and their relations to social status within the group. Aggressive Behavior. 1996; 22 (1):1–15.
  • Salmivalli C, Voeten M, Poskiparta E. Bystanders matter: Associations between reinforcing, defending, and the frequency of bullying behavior in classrooms. Journal of Clinical Child & Adolescent Psychology. 2011; 40 (5):668–676. [ PubMed : 21916686 ]
  • Sanchez M, Pollak S. Handbook of Developmental Social Neuroscience. de Haan M, Gunnar MR, editors. New York: Guilford Press; 2009. pp. 497–520. (Socio-emotional development following early abuse and neglect: Challenges and insights from translational research).
  • Sandi C, Haller J. Stress and the social brain: Behavioural effects and neurobiological mechanisms. Nature Reviews Neuroscience. 2015; 16 :290–304. [ PubMed : 25891510 ]
  • Scarr S, McCartney K. How people make their own environments: A theory of genotype→ environment effects. Child Development. 1983; 52 (2):424–435. [ PubMed : 6683622 ]
  • Schacter HL, White SJ, Chang VY, Juvonen J. “Why me?”: Characterological self-blame and continued victimization in the first year of middle school. Journal of Clinical Child & Adolescent Psychology. 2014; 44 (3):446–455. [ PMC free article : PMC6129379 ] [ PubMed : 24483145 ]
  • Schwartz D, Dodge KA, Coie JD. The emergence of chronic peer victimization in boys' play groups. Child Development. 1993; 64 (6):1755–1772. [ PubMed : 8112117 ]
  • Schwartz D, Gorman AH, Nakamoto J, Toblin RL. Victimization in the peer group and children's academic functioning. Journal of Educational Psychology. 2005; 97 (3):425–435.
  • Shakoor S, Jaffee SR, Andreou P, Bowes L, Ambler AP, Caspi A, Moffitt TE, Arseneault L. Mothers and children as informants of bullying victimization: Results from an epidemiological cohort of children. Journal of Abnormal Child Psychology. 2011; 39 (3):379–387. [ PMC free article : PMC4231790 ] [ PubMed : 20938734 ]
  • Shalev I, Moffitt TE, Sugden K, Williams B, Houts RM, Danese A, Mill J, Arseneault L, Caspi A. Exposure to violence during childhood is associated with telomere erosion from 5 to 10 years of age: A longitudinal study. Molecular Psychiatry. 2013; 18 (5):576–581. [ PMC free article : PMC3616159 ] [ PubMed : 22525489 ]
  • Shen J, Kudrimoti H, McNaughton B, Barnes C. Reactivation of neuronal ensembles in hippocampal dentate gyrus during sleep after spatial experience. Journal of Sleep Research. 1998; 7 (S1):6–16. [ PubMed : 9682188 ]
  • Shonkoff JP, Boyce WT, McEwen BS. Neuroscience, molecular biology, and the childhood roots of health disparities: Building a new framework for health promotion and disease prevention. Journal of the American Medical Association. 2009; 301 (21):2252–2259. [ PubMed : 19491187 ]
  • Shultz JM, Thoresen S, Flynn BW, Muschert GW, Shaw JA, Espinel Z, Walter FG, Gaither JB, Garcia-Barcena Y, O'Keefe K. Multiple vantage points on the mental health effects of mass shootings. Current Psychiatry Reports. 2014; 16 (9):1–17. [ PubMed : 25085235 ]
  • Sigurdson JF, Undheim AM, Wallander JL, Lydersen S, Sund AM. The long-term effects of being bullied or a bully in adolescence on externalizing and internalizing mental health problems in adulthood. Child and Adolescent Psychiatry and Mental Health. 2015; 9 (1):1–13. [ PMC free article : PMC4546259 ] [ PubMed : 26300969 ]
  • Sijtsema JJ, Veenstra R, Lindenberg S, Salmivalli C. Empirical test of bullies' status goals: Assessing direct goals, aggression, and prestige. Aggressive Behavior. 2009; 35 :57–67. [ PubMed : 18925635 ]
  • Smalley D, Banerjee R. The role of social goals in bullies' and victims' social information processing in response to ambiguous and overtly hostile provocation. Social Development. 2013; 23 (3):593–610.
  • Smith PK, Talamelli L, Cowie H, Naylor P, Chauhan P. Profiles of non-victims, escaped victims, continuing victims and new victims of school bullying. British Journal of Educational Psychology. 2004; 74 :565–581. [ PubMed : 15530202 ]
  • Sourander A, Jensen P, Rönning JA, Elonheimo H, Niemelä S, Helenius H, Kumpulainen K, Piha J, Tamminen T, Moilanen I, Almqvist F. Childhood bullies and victims and their risk of criminality in late adolescence. Archives of Pediatrics and Adolescent Medicine. 2007; 161 (6):546–552. [ PubMed : 17548758 ]
  • Sourander A, Brunstein KA, Kumpulainen K, Puustjärvi A, Elonheimo H, Ristkari T, Tamminen T, Moilanen I, Piha J, Ronning J. Bullying at age eight and criminality in adulthood: Findings from the Finnish Nationwide 1981 Birth Cohort Study. Social Psychiatry and Psychiatric Epidemiology. 2011; 46 (12):1211–1219. [ PubMed : 21120451 ]
  • Spear L. The Behavioral Neuroscience of Adolescence. New York: WW Norton & Company; 2010.
  • Spear LP. Adolescent neurodevelopment. Journal of Adolescent Health. 2013; 52 (2):S7–S13. [ PMC free article : PMC3982854 ] [ PubMed : 23332574 ]
  • Srabstein JC, McCarter RJ, Shao C, Huang ZJ. Morbidities associated with bullying behaviors in adolescents. School based study of American adolescents. International Journal of Adolescent Medicine and Health. 2006; 18 (4):587–596. [ PubMed : 17340850 ]
  • Stapinski LA, Bowes L, Wolke D, Pearson RM, Mahedy L, Button KS, Lewis G, Araya R. Peer victimization during adolescence and risk for anxiety disorders in adulthood: A prospective cohort study. Depression and anxiety. 2014; 31 (7):574–582. [ PMC free article : PMC4190687 ] [ PubMed : 24788688 ]
  • Sugden K, Arseneault L, Harrington H, Moffitt TE, Williams B, Caspi A. Serotonin transporter gene moderates the development of emotional problems among children following bullying victimization. Journal of the American Academy of Child & Adolescent Psychiatry. 2010; 49 (8):830–840. [ PMC free article : PMC2908591 ] [ PubMed : 20643316 ]
  • Swearer SM, Hymel S. Understanding the psychology of bullying: Moving toward a social-ecological diathesis–stress model. American Psychologist. 2015; 70 (4):344–353. [ PubMed : 25961315 ]
  • Tharp-Taylor S, Haviland A, D'Amico EJ. Victimization from mental and physical bullying and substance use in early adolescence. Addictive Behaviors. 2009; 34 (6):561–567. [ PMC free article : PMC2707251 ] [ PubMed : 19398162 ]
  • Thornberg R, Tenenbaum L, Varjas K, Meyers J, Jungert T, Vanegas G. Bystander motivation in bullying incidents: To intervene or not to intervene? Western Journal of Emergency Medicine. 2012; 13 (3):247–252. [ PMC free article : PMC3415829 ] [ PubMed : 22900122 ]
  • Thunfors P, Cornell D. The popularity of middle school bullies. Journal of School Violence. 2008; 7 (1):65–82.
  • Tilghman-Osborne C, Cole DA, Felton JW, Ciesla JA. Relation of guilt, shame, behavioral and characterological self-blame to depressive symptoms in adolescents over time. Journal of Social and Clinical Psychology. 2008; 27 (8):809–842. [ PMC free article : PMC4238306 ] [ PubMed : 25419043 ]
  • Ttofi MM, Farrington DP, Lösel F, Loeber R. Do the victims of school bullies tend to become depressed later in life? A systematic review and meta-analysis of longitudinal studies. Journal of Aggression, Conflict and Peace Research. 2011; 3 (2):63–73.
  • Unnever JD, Cornell DG. The culture of bullying in middle school. Journal of School Violence. 2003; 2 (2):5–27.
  • Vaillancourt T, Hymel S, McDougall P. Bullying is power: Implications for school-based intervention strategies. Journal of Applied School Psychology. 2003; 19 (2):157–176.
  • Vaillancourt T, Duku E, Decatanzaro D, Macmillan H, Muir C, Schmidt LA. Variation in hypothalamic–pituitary–adrenal axis activity among bullied and non-bullied children. Aggressive Behavior. 2008; 34 (3):294–305. [ PubMed : 18161876 ]
  • Vaillancourt T, Decatanzaro D, Duku E, Muir C. Androgen dynamics in the context of children's peer relations: An examination of the links between testosterone and peer victimization. Aggressive Behavior. 2009; 35 (1):103–113. [ PubMed : 19021234 ]
  • Vaillancourt T, Hymel S, McDougall P. Bullying in North American Schools. Espelage D, Swearer S, editors. New York: Taylor & Francis; 2010a. pp. 23–33. (Why does bullying hurt so much? Insights from neuroscience).
  • Vaillancourt T, McDougall P, Hymel S, Sunderani S. Handbook of Bullying in Schools: An International Perspective. Jimerson SR, Swearer SM, Espelage DL, editors. New York: Routledge; 2010b. pp. 211–222. (The relationship between power and bullying behavior).
  • Vaillancourt T, Duku E, Becker S, Schmidt LA, Nicol J, Muir C, MacMillan H. Peer victimization, depressive symptoms, and high salivary cortisol predict poorer memory in children. Brain and Cognition. 2011; 77 (2):191–199. [ PubMed : 21855200 ]
  • Vaillancourt T, Hymel S, McDougall P. The biological underpinnings of peer victimization: Understanding why and how the effects of bullying can last a lifetime. Theory Into Practice. 2013a; 52 (4):241–248.
  • Vaillancourt T, Brittain HL, McDougall P, Duku E. Longitudinal links between childhood peer victimization, internalizing and externalizing problems, and academic functioning: Developmental cascades. Journal of Abnormal Child Psychology. 2013b; 41 (8):1203–1215. [ PubMed : 23907699 ]
  • Vaillancourt T, Sanderson C, Arnold P, McDougall P. Handbook of Bullying Prevention: A Life Course Perspective. Bradshaw CP, editor. National Association of Social Workers Press; (The neurobiology of peer victimization: Longitudinal links to health, genetic risk, and epigenetic mechanisms). in press.
  • van Dam DS, van der Ven E, Velthorst E, Selten JP, Morgan C, de Haan L. Childhood bullying and the association with psychosis in non-clinical and clinical samples: A review and meta-analysis. Psychological Medicine. 2012; 42 (12):2463–2474. [ PubMed : 22400714 ]
  • van Geel M, Vedder P, Tanilon J. Relationship between peer victimization, cyberbullying, and suicide in children and adolescents. Journal of American Medical Association Pediatrics. 2014; 168 (5):435–442. [ PubMed : 24615300 ]
  • van Geel M, Goemans A, Vedder PH. The relation between peer victimization and sleeping problems: A meta-analysis. Sleep Medicine Reviews. 2015; 27 :89–95. [ PubMed : 26140869 ]
  • Vannucci M, Nocentini A, Mazzoni G, Menesini E. Recalling unpresented hostile words: False memories predictors of traditional and cyberbullying. European Journal of Developmental Psychology. 2012; 9 (2):182–194.
  • VanZomeren-Dohm AA, Pitula CE, Koss KJ, Thomas K, Gunnar MR. FKBP5 moderation of depressive symptoms in peer victimized, post-institutionalized children. Psychoneuroendocrinology. 2015; 51 :426–430. [ PMC free article : PMC4268402 ] [ PubMed : 25462914 ]
  • Veenstra R, Lindenberg S, Munniksma A, Dijkstra JK. The complex relation between bullying, victimization, acceptance, and rejection: Giving special attention to status, affection, and sex differences. Child Development. 2010; 81 (2):480–486. [ PubMed : 20438454 ]
  • Viding E, Blair RJR, Moffitt TE, Plomin R. Evidence for substantial genetic risk for psychopathy in 7-year-olds. Journal of Child Psychology and Psychiatry. 2005; 46 (6):592–597. [ PubMed : 15877765 ]
  • Vossekuil B, Fein RA, Reddy M, Borum R, Modzeleski W. The Final Report and Findings of the Safe School Initiative: Implications for the Prevention of the Safe School Initiative. Washington, DC: U.S. Secret Service and Department of Education; 2002.
  • Weaver IC, Cervoni N, Champagne FA, D'Alessio AC, Sharma S, Seckl JR, Dymov S, Szyf M, Meaney MJ. Epigenetic programming by maternal behavior. Nature Neuroscience. 2004; 7 (8):847–854. [ PubMed : 15220929 ]
  • Weiner B. An Attributional Theory of Motivation and Emotion. New York: Springer-Verlag; 1986.
  • Whelan YM, Kretschmer T, Barker ED. MAOA, early experiences of harsh parenting, irritable opposition, and bullying–victimization: A moderated indirect-effects analysis. Merrill-Palmer Quarterly. 2014; 60 (2):217–237.
  • Wilker S, Pfeiffer A, Kolassa S, Elbert T, Lingenfelder B, Ovuga E, Papassotiropoulos A, de Quervain D, Kolassa IT. The role of FKBP5 genotype in moderating long-term effectiveness of exposure-based psychotherapy for posttraumatic stress disorder. Translational Psychiatry. 2014; 4 (6):1–7. [ PMC free article : PMC4080328 ] [ PubMed : 24959896 ]
  • Williams KD, Bernieri FJ, Faulkner SL, Gada-Jain N, Grahe JE. The Scarlet Letter Study: Five days of social ostracism. Journal of Personal & Interpersonal Loss. 2000; 5 (1):19–63.
  • Wilson TD, Damiani M, Shelton N. Improving Academic Achievement: Impact of Psychological Factors on Education. Wilson TD, editor. San Diego, CA: Elsevier BV; 2002. pp. 89–108. (Improving the academic performance of college students with brief attributional interventions).
  • Wolke D, Woods S, Bloomfield L, Karstadt L. Bullying involvement in primary school and common health problems. Archives of Disease in Childhood. 2001; 85 (3):197–201. [ PMC free article : PMC1718894 ] [ PubMed : 11517098 ]
  • Wolke D, Lereya ST, Fisher H, Lewis G, Zammit S. Bullying in elementary school and psychotic experiences at 18 years: A longitudinal, population-based cohort study. Psychological Medicine. 2014; 44 (10):2199–2211. [ PubMed : 24342773 ]
  • Yang GS, McLoyd VC. Do parenting and family characteristics moderate the relation between peer victimization and antisocial behavior? A 5-year longitudinal study. Social Development. 2015; 24 :748–765.
  • Ybarra ML, Mitchell KJ, Wolak J, Finkelhor D. Examining characteristics and associated distress related to Internet harassment: Findings from the second Youth Internet Safety Survey. Pediatrics. 2006; 118 (4):e1169–e1177. [ PubMed : 17015505 ]

Somatization is “a syndrome of physical symptoms that are distressing and may not be fully explained by a known medical condition after appropriate investigation. In addition, the symptoms may be caused or exacerbated by anxiety, depression, and interpersonal conflicts, and it is common for somatization, depression, and anxiety to all occur together” ( Greenberg, 2016 ).

Consolidation of memory is a biological process where the information one learns is stabilized within neural circuits and placed into long-term memory through a complex orchestration of molecular-level change and gene activation within neurons.

Peer victimization was measured with a 21-item revised version of the Social Experiences Questionnaire. The measure assesses overt and relational victimization and frequency of different acts of victimization ( Rudolph et al., 2016 ).

Reijntjes and colleagues (2010, p. 244) defined peer victimization as taking “various forms, including direct bullying behaviors (e.g., teasing, physical aggression) as well as more indirect manifestations such as group exclusion or malicious gossip.” Hawker and Boulton (2000, p. 441) defined peer victimization as “the experience among children of being a target of the aggressive behavior of other children, who are not siblings and not necessarily age-mates.”

Peer victimization was measured using peer, self-, and teacher reports, including peer nominations, a four-item self-report victimization scale, and a six-item teacher report victimization scale ( Kochel et al., 2012 ).

Stapinski et al. (2014) used a modified version of the Bullying and Friendship Interview Schedule to assess self-reported peer victimization. This measure includes items on overt victimization, such as threats, physical violence, and relational victimization.

Nonclinical psychotic symptoms are symptoms that do not meet the clinical definition for those psychotic disorders associated with such symptoms.

Peer victimization was measured using a modified six-item version of the Peer Victimization Scale, which asks students to select a statement that is most like them. Higher scores indicated higher levels of peer victimization ( Juvonen et al., 2011 ).

Peer victimization was measured using a 16-item peer nomination interview and a teacher-completed Social Behavior Rating Scale ( Schwartz et al., 2005 ).

Peer victimization is used here to include the broader category of bullying, peer victimization, and bullying behavior.

Psychotic experiences included hallucinations (visual and auditory), delusions (spied on, persecution, thoughts read, reference, control, grandiosity), and experiences of thought interference (broadcasting, insertion, and withdrawal), and any unspecified delusions.

This section is adapted from Rose (2015 , pp. 18-21).

A telomere is the “segment at the end of each chromosome arm which consists of a series of repeated DNA sequences that regulate chromosomal replication at each cell division.” See http://ghr ​.nlm.nih.gov/glossary=telomere [December 2015]. Telomeres are associated with “chromosomal stability” and the regulation of “cells' cellular replicative lifespan” (Kiecolt-Glaser et al., 2011, p. 16).

Peer victimization was measured by a teacher-reported seven-item measure with items measuring broader peer victimization (Hanish et al., 2004).

Peer victimization was measured using the Revised Peer Experiences Questionnaire, which assesses overt, relational, and reputational victimization by peers (McLaughlin et al., 2009).

High risk was defined as a mother who had her first child at age 20 or younger ( Moffitt, 2002 ).

Peer victimization was assessed through teacher, peer, and self-ratings. Children were asked to circle photographs of two classmates who get called names by other children and who are often pushed or hit by other children.

An allele is an alternate form of the same gene. Except for the XY chromosomes in males, human chromosomes are paired, so a cell's genome usually has two alleles for each gene.

The MAOA genotype has been called the “warrior” gene because of its association with aggression in studies using surveys and observations ( McDermott et al., 2009 ).

Peer victimization was measured using a teacher-report 3-item scale that assessed relational victimization in the classroom ( Kretschmer et al., 2013 ).

The FKBP5 rs1360780 gene is associated with a number of different psychological disorders ( Wilker et al., 2014 ).

VanZomeren-Dohm and colleagues (2015 measured peer victimization using the MacArthur Health and Behavior Questionnaire Parent-Form, version 2.1, in which parents reported on their children's experiences of overt peer victimization.

DNA methylation is a heritable epigenetic mark involving the covalent transfer of a methyl group to the C-5 position of the cytosine ring by DNA methyltransferases (a family of enzymes that act on DNA). Cytosine is one of the four bases that occur in varying sequences to form the “code” carried by strands of DNA ( Robertson, 2005 ).

Exposure to violence included domestic violence, bullying victimization, and physical abuse by an adult.

Cumulative violence exposure was measured by an index that summed each type of violence exposure.

  • Cite this Page Committee on the Biological and Psychosocial Effects of Peer Victimization: Lessons for Bullying Prevention; Board on Children, Youth, and Families; Committee on Law and Justice; Division of Behavioral and Social Sciences and Education; Health and Medicine Division; National Academies of Sciences, Engineering, and Medicine; Rivara F, Le Menestrel S, editors. Preventing Bullying Through Science, Policy, and Practice. Washington (DC): National Academies Press (US); 2016 Sep 14. 4, Consequences of Bullying Behavior.
  • PDF version of this title (3.8M)

In this Page

  • MULTIPLE EXPOSURES TO VIOLENCE

Other titles in this collection

  • The National Academies Collection: Reports funded by National Institutes of Health

Related information

  • PMC PubMed Central citations
  • PubMed Links to PubMed

Recent Activity

  • Consequences of Bullying Behavior - Preventing Bullying Through Science, Policy,... Consequences of Bullying Behavior - Preventing Bullying Through Science, Policy, and Practice

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

Connect with NLM

National Library of Medicine 8600 Rockville Pike Bethesda, MD 20894

Web Policies FOIA HHS Vulnerability Disclosure

Help Accessibility Careers

statistics

Examining the Effectiveness of School-Bullying Intervention Programs Globally: a Meta-analysis

  • Original Article
  • Open access
  • Published: 21 February 2019
  • Volume 1 , pages 14–31, ( 2019 )

Cite this article

You have full access to this open access article

  • Hannah Gaffney   ORCID: orcid.org/0000-0001-9677-0218 1 ,
  • David P. Farrington 1 &
  • Maria M. Ttofi 1  

83k Accesses

155 Citations

80 Altmetric

Explore all metrics

This article presents results from an extensive systematic and meta-analytical review of the effectiveness of school-based bullying prevention programs. Its main aim is to explore the results of this meta-analysis specifically in regard to variations in the effectiveness of school-bullying programs globally and the effectiveness of specific anti-bullying programs. Our meta-analysis included 100 independent evaluations, and found that, overall, programs were effective in reducing school-bullying perpetration and victimization. In the present paper, we focused on 12 countries (e.g., Italy, Norway, USA, UK), three regions (i.e., Europe, North America, and Scandinavia) and four anti-bullying programs (i.e., KiVa, NoTrap!, OBPP, and ViSC) with multiple evaluations. Our results showed that anti-bullying programs evaluated in Greece were the most effective in reducing bullying perpetration, followed by Spain and Norway. Anti-bullying programs evaluated in Italy were the most effective in reducing bullying victimization, followed by Spain and Norway. Evaluations conducted in North America were the most effective in reducing bullying perpetration, and evaluations conducted in Scandinavia were the most effective in reducing bullying victimization. Evaluations of the Olweus Bullying Prevention Program produced the largest effect sizes for bullying perpetration outcomes, but the NoTrap! Program was the most effective in reducing bullying victimization. We also systematically review the core components of the intervention programs and make recommendations for researchers, practitioners, and policy makers.

Similar content being viewed by others

essay on prevention of bullying

What Works for Whom in School-Based Anti-bullying Interventions? An Individual Participant Data Meta-analysis

Maud Hensums, Brechtje de Mooij, … Geertjan Overbeek

essay on prevention of bullying

Bullying Prevention in Turkish Schools: Evaluation of the ViSC Program

essay on prevention of bullying

A Meta-analytic Review of School-Based Anti-bullying Programs with a Parent Component

Yuanhong Huang, Dorothy L. Espelage, … Jun Sung Hong

Avoid common mistakes on your manuscript.

Introduction

Bullying remains a ubiquitous problem internationally and is an important topic for effective intervention and empirical research. Bullying is characterized by three core elements, namely (1) an intention to harm; (2) repetitive in nature; and (3) a clear power imbalance between perpetrator and victim (Centers for Disease Control and Prevention 2014 ; Farrington 1993 ; Olweus 1992 ). In other words, a bully is an individual who intends to cause harm to a victim, or victims, repeatedly, over a long period of time. Additionally, victims of bullying will feel that they cannot easily defend themselves against a bully, either due to a physical or social power imbalance.

Recent research has highlighted the various forms that bullying can take, not only amongst school children and adolescents but also between adults too, particularly within the workplace environment (Kowalski et al. 2018 ). Moreover, bullying can include relational, verbal, or physical behaviors. Most recently, online aggressive behaviors that are consistent with definitions of school bullying have been defined as cyberbullying (Bauman 2013 ; Betts 2016 ). The present review, however, is concerned only with school-bullying, specifically, bullying that occurs in schools involving children and adolescents, typically aged between 4 and 18 years old. School bullying is a complex social phenomenon and can commonly involve the whole peer group (Salmivalli 2010 ).

Outcomes of School Bullying

The negative outcomes of school-bullying perpetration and victimization are well documented in the research literature. These outcomes highlight the need for effective intervention and prevention programs to reduce school-bullying amongst children and adolescents around the world. Cross-sectional studies have found that bullying perpetration and victimization experiences are associated with worrying mental health outcomes, such as increased suicidal ideation (e.g., Hinduja and Patchin 2010 ; Holt et al. 2015 ; Klomek et al. 2010 ). In addition, adolescent victims of school bullying have been found to report higher levels of social anxiety (e.g., Hawker and Boulton 2000 ) and depression (e.g., Ttofi et al. 2011a ) in comparison to their non-victimized peers. Bullies, on the other hand, are more likely to carry weapons (e.g., Valdebenito et al. 2017 ) or use drugs (e.g., Ttofi et al. 2016 ; Valdebenito et al. 2015 ).

A recent review of systematic reviews concluded that the outcomes of school-bullying behaviors can occur not only concurrently with these experiences but also during adulthood (Zych et al. 2015 ). For example, longitudinal studies have suggested that individuals who bully others in childhood are more likely to be violent (e.g., Ttofi et al. 2012 ) and offend (e.g., Ttofi et al. 2011b ) as adults. While there is limited understanding of how these outcomes may vary between bullies and victims in different countries, researchers have suggested that experiences of school bullying may function as stepping stones towards many undesirable life outcomes (Arsenault et al. 2010 ). Thus, bullying is not only a concern for parents and educators but it is a public health concern also (Masiello and Schroeder 2013 ), and it is imperative that effective intervention efforts are put in place (Ttofi 2015 ).

Internationally, Due et al. ( 2005 ) reported that the risk of physical and psychological symptoms increased with higher levels of exposure to bullying across 28 countries. More recently, Fry et al. ( 2018 ) conducted an extensive meta-analysis across 21 countries to examine the relationship between childhood violence and educational outcomes. Predictors included school-bullying perpetration and victimization, as well as cyberbullying and peer-to-peer victimization (Fry et al. 2018 ). This study concluded that experiences of bullying in childhood were significantly related to higher rates of school dropout and absenteeism. Bullying was also related to a decrease in school graduation and lower academic achievement overall, although, the latter relationship was not statistically significant (Fry et al. 2018 ).

International Prevalence of School Bullying

A recent report published by the United Nations Educational, Scientific, and Cultural Organization (UNESCO 2018 ) proposes that creating educational spaces that are free from violence and safe learning environments for all children remains a global priority. This report outlines that bullying and other forms of violence affect approximately one-third of children and adolescents, but the rates of bullying victimization vary between regions. Using international self-report data (e.g., Health Behavior of School Children survey; HBSC), this report suggests that reports of bullying victimization are highest in regions such as the Middle East (41.1%), North Africa (42.7%), and sub-Saharan Africa (48.2%). Additionally, reports of bullying victimization were comparatively low in North America (31.7%) and lowest in Europe (25%), the Caribbean (25%), and Central America (22.8%).

An extensive meta-analysis reported that the mean prevalence of involvement in school bullying was 35% across 80 different countries (Modecki et al. 2014 ). Recent analyses of the Health Behaviour in School-aged Children (HBSC) study found interesting trends in bullying victimization across male and female schoolchildren (aged 11, 13, and 15 years old) from 33 countries (Chester et al. 2015 ). The authors suggested that, overall, occasional school-bullying victimization had decreased from 33.5% in 2001–2002 to 29.2% in 2009–2010, while chronic school-bullying victimization had also decreased from 12.7% in 2001–2002 to 11.3% in 2009–2010. This report also found that, while reports of school-bullying victimization were declining in one-third of countries included in the analysis, there are still large variations in bullying victimization across countries.

Researchers have attempted to identify factors that may explain these geographical differences. Elgar, Craig, Boyce, Morgan, and Vella-Zarb ( 2009 ) concluded that school-bullying prevalence varied according to rates of income inequality across 37 countries. Specifically, higher income inequality was associated with more reports of school bullying amongst adolescents. After controlling for income inequality, family and school support were associated with lower levels of school-bullying perpetration (Elgar et al. 2009 ). However, the relationship between income inequality and school-bullying victimization was not consistent across each of the countries included in the analysis.

Definitions of school bullying, and behaviors that constitute bullying, can also differ between countries. Previous research conducted by Smith, Kwak, and Toda ( 2016 ) showed that school bullying in Eastern cultures manifests more often as exclusion or isolation of an individual victim. Specifically in Japan, ijime involves a group excluding or isolating one student. In comparison, school bullying in Western cultures comprises a wider range of physical, verbal, and relational forms of aggression (e.g., Toda 2016 ). Thus, standardized international surveys may be insufficient at detecting different manifestations of bullying in different cultures which may in turn influence prevalence rates.

Regardless of international variation, bullying behaviors remain very frequent. One in four schoolchildren in Europe to nearly one in two children in sub-Saharan Africa report bullying victimization (UNESCO 2018 ). It is imperative, therefore, that practitioners should implement effective anti-bullying programs in their schools to protect students from bullying and its potential negative outcomes. From the perspective of international human rights law, the right to be safe at school and not be subjected to the aggression and victimization associated with bullying should be afforded to all children (Olweus and Limber 2010 ; Convention on the Rights of the Child 1989; Universal Declaration of Human Rights 1948).

Effectiveness of School-Bullying Intervention Programs

There have been many previous attempts to establish what works in bullying intervention and prevention. Farrington and Ttofi ( 2009 ) found that school-based anti-bullying programs were effective in reducing bullying perpetration by approximately 20–23% and bullying victimization by approximately 17–20%. This report identified that evaluations conducted in Norway were significantly more likely to report desirable results in comparison to evaluations conducted in other locations (Farrington and Ttofi 2009 ). The authors also reported the difference between evaluations conducted in Europe and elsewhere, but the difference in the odds ratio mean effect sizes was not statistically significant (p. 140).

More recent analyses have found that anti-bullying programs are effective in reducing both school-bullying perpetration and victimization, but these reviews are limited in various ways. For example, some previous systematic reviews have failed to conduct a meta-analysis to quantify the effectiveness of school-bullying intervention programs (i.e., Cantone et al. 2015 ; Chalamandaris and Piette 2015 ; Evans et al. 2014 ). Therefore, we cannot adequately quantify and judge the objective effectiveness of included anti-bullying programs.

Some previous meta-analyses have over-restricted their analysis to include only randomized controlled trials (i.e., Jiménez-Barbero et al. 2016 ), or evaluations published after 2000 and conducted with participants between the ages of 6 and 16 years old (i.e., Jiménez-Barbero et al. 2012 ). These restrictive inclusion criteria may unnecessarily exclude studies that used non-randomized quasi-experimental designs or younger/older children and adolescents. Often in school-based evaluation research, randomized controlled trials are not feasible and thus, high-quality non-randomized quasi-experimental designs are an appropriate alternative evaluation design. Furthermore, although forms of bullying may change with age, bullying behaviors have been reported in kindergarten-aged students and adolescents over the age of 16 (UNESCO 2018 ).

Objectives of the Current Report

A recent comprehensive systematic review and meta-analysis of the effectiveness of school-based bullying prevention programs found overall that anti-bullying programs are effective (Gaffney, Ttofi, and Farrington 2019a ). This meta-analysis found that anti-bullying programs were collectively effective in reducing school-bullying perpetration by around 19–20% (odds ratio = 1.309) and school-bullying victimization by around 15–16% (odds ratio = 1.244). This study included evaluations of many different anti-bullying programs from across the world. However, as you would expect, there was significant heterogeneity in the results (see Gaffney et al. 2019b ).

Thus, the objective of the present report is to explore some possible explanations for the variations in results between evaluations of anti-bullying programs. We use the data collected for the aforementioned review and evaluated the effectiveness of anti-bullying programs according to moderator variables. The present report explores variables such as the location of the evaluation and the particular intervention program that was evaluated. We aim to establish the effectiveness of existing anti-bullying efforts globally, to better inform ongoing research and potential translation of existing programs between countries. We also aim to identify and review existing anti-bullying programs that are widely disseminated or have been implemented across different settings and populations.

We suggest that the results of this analysis will be useful to researchers, policy makers, and practitioners (e.g., teachers, principals, school counselors/psychologists). It is important for all parties involved in anti-bullying work to understand the mechanisms of change underlying effective anti-bullying programs, and also to appraise the existing evidence on “what works” in bullying prevention. Therefore, we hope that this review will inform practitioners, such as school staff or counselors/psychologists, when deciding what anti-bullying program to implement in their schools.

Systematic Review

In order to locate studies for our review, we conducted a series of extensive systematic searches of the literature. Boolean searches were conducted using combinations of the following keywords: bully* ; victim *; bully-victim ; school ; intervention ; prevention ; program *; evaluation ; effect *; and anti-bullying . We searched several online databases, including, but not limited to, Web of Science, PsychINFO, EMBASE, ERIC, DARE, Google Scholar, and Scopus. Databases of unpublished reports (e.g., ProQuest) were also searched to include gray literature in this review. The inclusion of unpublished studies should reduce any potential publication bias (Easterbrook et al. 1991 ; McAuley et al. 2000 ).

In addition, studies both included and excluded by previous meta-analyses and systematic reviews (i.e., Cantone et al. 2015 ; Chalamandaris and Piette 2015 ; Evans et al. 2014 ; Jiménez-Barbero et al. 2016 ; Jiménez-Barbero et al. 2012 ) were reviewed to identify any potentially includable studies for the present review. In total, 49 studies that were included in a previous systematic review (i.e., Farrington and Ttofi ( 2009 )) were included in our updated analysis. New searches were conducted for studies published from 2009 to the end of December 2016.

To be included in the updated meta-analysis, primary studies were measured against a set of pre-determined inclusion criteria. Namely, studies must (1) describe an evaluation of a school-based anti-bullying program that was implemented with school-age participants; (2) utilize an operational definition of school bullying that coincides with existing definitions (e.g., CDC 2014 ; Farrington 1993 ; Olweus 1992 ); (3) measure school-bullying perpetration and/or victimization using quantitative measures, such as self-, peer-, or teacher-report questionnaires; and (4) use an experimental or quasi-experimental design, with one group receiving the intervention and another (control group) not receiving the intervention.

Search Results

Our searches of the literature produced approximately 20,000 reports that were screened for eligibility. Based on titles and abstracts, 474 of these results were retained for further screening. The majority of these studies were excluded for various reasons. Our initial wave of screening excluded 107 studies that did not actually evaluate a specific anti-bullying program, 108 studies that reviewed several anti-bullying programs, and 43 studies that did not report empirical quantitative data.

Following more in-depth screening of the methodologies and results of the remaining studies, 133 studies were excluded because they (1) reported irrelevant outcomes; (2) did not have an adequate control group; or (3) did not meet the specified methodological criteria. For a detailed description of the screening process and how we determined which studies were included, please see Gaffney et al. ( 2019b ). Following screening, 83 studies published after 2009 were eligible for inclusion in the systematic review.

In total however, 141 studies were eligible for inclusion in the present systematic review. This number includes 83 studies identified in the searches described here, five studies identified after searches were completed, and 53 studies that were included in the previous systematic review by Farrington and Ttofi ( 2009 ). However, only 100 primary evaluations were included in our meta-analysis, as a number of studies were excluded for a number of different reasons. For example, 10 studies lacked statistical information (needed to estimate effect sizes), 26 reported outcomes of evaluations conducted with the same sample (i.e., non-independent studies, repeat publications, or follow-up studies), and the remaining studies used an “other” experimental-control design (i.e., non-randomized with no before and after measures).

Included evaluations used one of three experimental methodologies: (1) randomized controlled trials; (2) quasi-experimental designs with before and after measures; and (3) age cohort designs. Randomized controlled trials are considered the gold standard in experimental evaluations (Weisburd et al. 2001 ) and involve the random assignment of individuals, or clusters of individuals, to experimental and control conditions. Quasi-experiments are conceptually similar to randomized controlled trials but do not use random assignment. As such, the validity of results may be reduced so in our meta-analysis, we only included quasi-experiments that measured school bullying before and after the implementation of an intervention. Age cohort designs involve students of a particular age assessed for relevant outcomes in the first year of the intervention and this data acts as a control for students in the same school and the same age tested after the intervention has taken place. For detailed descriptions of these 100 evaluations, please refer to Gaffney et al. ( 2019b ), for studies published after 2009, and to the original systematic review by Farrington and Ttofi ( 2009 ), for studies published before 2009.

  • Meta-analysis

From the 100 evaluations, we estimated 103 independent effect sizes for the effectiveness of anti-bullying programs in reducing bullying perpetration and bullying victimization. The majority of effect sizes were corrected for the effect of clustering (i.e., the allocation of groups, classes, or schools, rather than individuals, to experimental conditions) which is a common approach in school-based evaluation studies (Donner et al. 2001 ). Our meta-analysis included evaluations that were conducted using randomized-controlled designs ( n  = 45 effect sizes), quasi-experimental designs with before and after measures of bullying outcomes ( n  = 44 effect sizes), and age cohort designs ( n  = 14 effect sizes).

The Comprehensive Meta-analysis software was used to conduct our analysis of the effectiveness of anti-bullying programs. Gaffney et al. ( 2019b ) presented the results of this analysis using three different models of meta-analysis and highlighted the strengths and weaknesses of each approach. For the present report, the results will be presented only using the multiplicative variance adjustment model (MVA; Farrington and Welsh 2013 ). This model of meta-analysis overcomes the problems associated with both the fixed-effects model (i.e., the assumption of a normal distribution of studies, even though homogeneity between primary studies is rare) and the random effects model (i.e., the additive adjustment for heterogeneity resulting in disproportionate weight given to smaller studies, which is undesirable).

We also translated odds ratio effect sizes to percentages to more effectively communicate the effectiveness of school-based anti-bullying programs. A clear example is provided by Ttofi and Farrington (2011), but this process involves assuming equal allocation of participants to experimental and control conditions in primary evaluations. For example, if there were around 55 bullies and around 145 non-bullies in the control condition ( n  = 200) and approximately 45 bullies and approximately 155 non-bullies in the experimental condition ( n  = 200), the OR would be about 1.3. This relates to a reduction in bullying perpetration of approximately 19–20%. Following this logic, we were able to translate ORs to approximate percentage decreases in bullying behaviors.

Coding Moderator Variables

For the purpose of the present report, we coded each of the 100 evaluations according to three moderators. Firstly, the country in which the evaluation took place was recorded (e.g., Australia, Sweden, or the USA). Secondly, for comparison, we coded the world region in which this country lies. For example, studies conducted in Italy, France, Spain, etc. were coded as the region “Europe,” and studies conducted in the USA or Canada were coded as “North America.” Evaluations conducted in Finland, Norway, or Sweden were coded as the region “Scandinavia,” but, an additional category (named EU) was created to encompass all European studies (i.e., inclusive of Scandinavian countries).

Both the country and regional information of all was coded all except one country. Sapouna et al. ( 2010 ) evaluated the FearNot! Virtual-learning intervention program in both the UK and Germany. Therefore, this study was not included in either the UK or German evaluations but was included in regional analysis as a European study. Thirdly, we also recorded the specific intervention program evaluated in each primary study. For example, some anti-bullying programs are widely disseminated and have been evaluated repeatedly in different locations and samples (e.g., KiVa or the Olweus Bullying Prevention Program).

Systematic Review Results

Evaluations globally.

Of the 100 evaluations included in our meta-analysis of school-based anti-bullying programs, the majority (80 for perpetration, 84 for victimization) were conducted in one of 12 different countries (i.e., Australia, Canada, Cyprus, Finland, Germany, Greece, Italy, Netherlands, Norway, Spain, UK, USA). We also identified singular evaluations conducted in Austria (Yanagida et al. 2016 ); Brazil (da Silva et al. 2016 ); China (Ju et al. 2009 ); Czechoslovakia (modern day Czech Republic and Slovakia; Rican, Ondrova, and Svatos 1996 ); Hong Kong (Wong et al. 2011 ); Ireland (O’Moore and Minton 2004 ); Malaysia (Yaakub et al. 2010 ); Romania (Trip et al. 2015 ); Sweden (Kimber et al. 2008 ); South Africa (Meyer and Lesch 2000 ); Switzerland (Alsaker and Valkanover 2001 ); and Zambia (Kaljee et al. 2017 ).

Repeatedly Evaluated Anti-bullying Programs

We found that very few specific anti-bullying programs had been implemented and evaluated more than once using independent samples. Sixty-five different school-based bullying intervention and prevention programs were included in our meta-analysis, but only eight were repeatedly evaluated (i.e., Bully Proofing Your School; the fairplayer.manual; KiVa; NoTrap!; OBPP; Second Step; Steps to Respect; ViSC). Moreover, of these programs, only four were evaluated more than twice across different locations with different evaluators (i.e., KiVa, OBPP, NoTrap!, and ViSC). The following sections of this report outline the key features of these programs. These four studies are outlined in Table 1 .

KiVa Anti-bullying Program

The KiVa anti-bullying program was developed and widely disseminated in Finland from 2007 to the present (Kärnä et al. 2013 ). The program was developed on the basis on several theoretical models of human social behavior, such as Bandura’s (1989) social-cognitive theory and the complex involvement of peers in school-bullying scenarios (e.g., Salmivalli 2010 ). Thus, the KiVa anti-bullying program targets bystanders in bullying situations, with the aim of reducing the social rewards for bullies and in turn reducing their bullying behaviors (Kärnä et al. 2013 ). The program is composed of three age-appropriate curriculum materials that focus on enhancing empathy, self-efficacy, and anti-bullying attitudes of bystanders.

Kärnä et al. ( 2011a , b , 2013 ) reported that trained teachers implement the KiVa intervention program in their classrooms and are provided with detailed lesson plans, which include various activities, such as group discussion, role-play, and short anti-bullying videos. Classroom anti-bullying rules are also devised throughout lessons. The KiVa program also includes a virtual-learning element, with primary school students playing an anti-bullying computer game both during and between lessons. Secondary school students are introduced to “KiVa Street” which is an online forum, providing vast information on bullying-related topics. Kärnä et al. ( 2011a ) state that the KiVa program includes many features identified by a previous review (Farrington and Ttofi 2009 ) as being significantly effective intervention components. For example, it includes disciplinary methods, improved playground supervision, teacher training, classroom rules, a whole-school anti-bullying policy, information for parents, videos, and cooperative group work (Kärnä et al. 2011a , p. 797).

Our systematic searches identified 16 potentially includable evaluations of the KiVa anti-bullying intervention (i.e., Ahtola et al. 2012 , 2013 ; Garandeau et al. 2014a , b ; Haataja et al. 2014 ; Hutchings and Clarkson 2015 ; Kärnä et al. 2011a , b , 2013 ; Nocentini and Menesini 2016 ; Noland 2011 ; Sainio et al. 2012 ; Salmivalli et al. 2012 ; Williford et al. 2012 ; Williford et al. 2013 ; Yang and Salmivalli 2014 ). Of these 16 studies, only four met our inclusion criteria and were included in our meta-analysis (i.e., Kärnä et al. 2011a , b , 2013 ; Nocentini and Menesini 2016 ). These studies presented the results of nationwide evaluations of the KiVa anti-bullying program using an age cohort design (i.e., Kärnä et al. 2011a ) and a randomized controlled trial (i.e., Kärnä et al. 2011b , 2013 ). Additionally, Nocentini and Menesini ( 2016 ) reported the results of the implementation and evaluation of the KiVa anti-bullying program in Italy using a randomized controlled trial design.

Noncadiamointrappola (let us Not Fall Into a Trap), or NoTrap!, is a web-based anti-bullying program that has been developed and evaluated in Italian high schools (Menesini et al. 2012 ). The intervention involves actively engaging students in the development of a website to promote anti-bullying. In addition, a number of participating students are enrolled as peer-educators throughout the intervention. These students act as moderators of the online anti-bullying forum, regulating discussion threads and responding to users’ questions and concerns (Menesini et al. 2012 ).

Additionally, peer-educators hold workshops offline with participating students to highlight the key issues surrounding both school- and cyberbullying (Palladino et al. 2016 ). Offline activities incorporate several elements that focus on (1) victims’ roles and victim support; (2) involving bystanders in bullying; (3) greater involvement of teachers; and (4) creation of a Facebook group to supplement online forum materials (Palladino et al. 2012 ). Classroom workshops target empathy and problem-solving skills (Palladino et al. 2016 ).

Our meta-analysis included four independent evaluations of the NoTrap! program in Italian secondary schools using quasi-experimental designs with before and after measures of school- and cyberbullying. Menesini et al. ( 2012 ; Study 1), implemented the program with 386 9th to 13th grade students during the December 2009 to June 2010 academic year. Palladino et al. ( 2012 ) and Menesini et al. ( 2012 ; Study 2) reported the results of the implementation and evaluation during the December 2010 to June 2011 academic year. Finally, Palladino et al. ( 2016 ) reported the results of two trials of the NoTrap! program with 9th grade students from 15 secondary schools, for the 2011/12 (Trial 1) and 2012/13 (Trial 2) academic years.

Olweus Bullying Prevention Program

It can be argued that the Olweus Bullying Prevention Program (OBPP; Olweus 1993a , b ) was the original whole-school anti-bullying program. This program aims to improve the school environment in order to reduce existing bullying problems and prevent further instances of bullying (Olweus et al. 1999 ). The program includes elements at many levels, specifically, school, classroom, individual, and community levels (Olweus et al. 2007 ). Intervention components are guided by four key principles, namely, adults, both at school and home, should (1) show warmth and positivity towards students; (2) set strict limits and restrictions on unacceptable student behavior; (3) apply consistent and non-aggressive consequences; and (4) act as positive and authoritative role models (Olweus and Limber 2010 , p. 126).

Olweus and Limber (Olweus and Limber 2010 , p. 127, see Table 1 ) specify that, at the school-level, the OBPP intervention involves establishing a Bullying Prevention Coordinating Committee (BPCC) that is comprised of school staff, parents, and members of the wider community. Intensive training is also provided for staff, and regular staff discussion groups are held. School rules against bullying are implemented at the whole-school and classroom levels, and a school-wide “kick off” event is held to launch the start of the intervention. At the individual level, intervention components include “hot-spot” supervision (i.e., increased staff presence at locations around the school where bullying is known to occur). The intervention also targets specific individuals who are recognized as bullies and victims, and their respective parents. Individual-specific intervention strategies are also designed for students involved in bullying.

Our meta-analysis of school-based anti-bullying programs included 12 independent evaluations of the OBPP intervention, largely implemented in Norway and the USA (e.g., Finn 2009 ; Limber et al. 2018 ; Losey 2009 ; Purugulla 2011 ). We also identified one evaluation of the OBPP in Malaysia (i.e., Yaakub et al. 2010 ). The OBPP was largely evaluated using quasi-experimental designs with before and after measures, or age cohort designs. The OBPP can be implemented with children and adolescents of a range of ages. For example, Finn ( 2009 ) implemented and evaluated the program with elementary schoolchildren, Purugulla ( 2011 ) implemented the program with middle school students, and Losey ( 2009 ) and Yaakub et al. ( 2010 ) implemented the program with secondary school students. Several of the OBPP evaluations that were included in our meta-analysis were implemented with students from a range of grades (e.g., Limber et al. 2018 ).

Viennese Social Competence Program

The Viennese Social Competence (ViSC) intervention program approaches bullying prevention from a socio-ecological perspective (Bronfenbrenner 1979 ; Swearer and Espelage 2004 ). This intervention targets not only individual students but also includes teachers, parents, and school staff, from a social learning theory (Bandura 1977 ) perspective. The ViSC program ensures that teachers have a shared responsibility to prevent bullying perpetration and victimization amongst students. The aim of the ViSC program is to reduce aggressive and bullying behaviors and also to create social and intercultural competencies within the school environment (Gradinger et al. 2015 ).

Designed to be implemented with secondary school students, the ViSC program is a 1-year program and adopts a “train-the-trainer” model. In other words, experts train teachers, who in turn train their students (Gradinger et al. 2015 ). The first semester of the program incorporates school-level intervention components, implemented with teachers and school staff. Participants are trained in how to recognize and tackle bullying scenarios and implement preventative measures at the school- and class-levels. Participating students also complete 13 lessons that follow a student-centered approach. Lessons one to eight focus on bullying behaviors and require students to actively work together to develop ways to prevent aggressive behavior in their respective classes. In the remaining five lessons, students work together on a class project to achieve a positive common goal and practice their social skills (Atria et al. 2007 ; Gradinger et al. 2015 ).

Our systematic review included five evaluations of the ViSC program, implemented in Austria (Gradinger et al. 2015 ; Yanagida et al. 2016 ); Cyprus (Solomontos-Kountouri et al. 2016 ); Germany (Gollwitzer et al. 2006 ); and Romania (Trip et al. 2015 ). One evaluation (i.e., Trip et al. 2015 ) of the ViSC program also implemented additional cognitive-behavioral intervention lessons, based on Rational Emotive Behavioral Education (REBE).

Meta-analysis Results

Overall, our meta-analysis found that anti-bullying programs were effective in reducing both school-bullying perpetration (OR = 1.324; 95% CI 1.27–1.38; p  < 0.001) and school-bullying victimization (OR = 1.248; 95% CI 1.27–1.38; p  < 0.001) outcomes. We estimated that this result corresponds to an approximate reduction of 19–20% and 15–16% for bullying perpetration and victimization respectively.

While the mean effect sizes suggest that anti-bullying programs are effective, there was significant heterogeneity for both bullying perpetration ( Q  = 323.39; p  < 0.001) and bullying victimization ( Q  = 387.26; p  < 0.001) outcomes. This result is not surprising in light of the large number of studies included in our meta-analysis, and the wide array of countries and intervention programs represented. Therefore, the aim of the present report is to explore variations in the effectiveness of intervention programs between countries and regions and specific anti-bullying programs.

School-Bullying Perpetration

Table 2 presents the effectiveness of anti-bullying programs across 22 different countries for bullying perpetration outcomes. Table 2 shows that, amongst international locations where more than one evaluation was conducted, evaluations carried out in Greece were the most effective in significantly reducing bullying perpetration, followed by Norway, Italy, the USA, and Finland. When singular evaluations were included, the anti-bullying program implemented in the former Czechoslovakia had the largest effect size for bullying perpetration, followed by Ireland. Effect sizes for bullying perpetration across all 22 countries included in our meta-analysis are represented graphically in Fig.  1 .

figure 1

Forest plot of weighted mean odds ratios for bullying perpetration outcomes across 22 different countries. Odds ratios are shown on a logarithmic scale

School-Bullying Victimization

Table 2 also summarizes the effectiveness of anti-bullying programs across 21 different countries for bullying victimization outcomes. Amongst international locations where more than one evaluation was conducted, evaluations conducted in Italy were the most effective in significantly reducing bullying victimization, followed by Spain, Norway, the USA, and Finland. Additionally, evaluations conducted in Germany and the UK were significantly effective. When singular evaluations were included, the anti-bullying program implemented in Austria had the largest effect size for bullying victimization, followed by Switzerland. Effect sizes for bullying victimization across all 21 countries included in our meta-analysis are represented graphically in Fig.  2 .

figure 2

Forest plot of weighted mean odds ratios for bullying victimization outcomes across 21 different countries. Odds ratios are shown on a logarithmic scale

Comparing Regional Effectiveness

In addition to exploring the effectiveness of anti-bullying programs conducted in individual countries, we also estimated effect sizes for different regions. Table 3 shows the weighted mean effect sizes across seven different geographical regions for school-bullying perpetration and victimization outcomes. We were able to code effect sizes for seven regions: Africa, Asia, Australia, Europe (excluding Scandinavia), North America, South America, and Scandinavia. The majority of studies were conducted in either Europe, North America, or Scandinavia. We also estimated a weighted mean effect size for studies conducted in Europe (including Scandinavia).

In regard to school-bullying perpetration outcomes, evaluations conducted in North America were the most effective, followed by Scandinavian studies, and then European studies. For school-bullying victimization outcomes, evaluations conducted in Scandinavia were the most effective. Evaluations conducted in Europe were the second most effective, followed by North American studies. When weighted mean effect sizes were estimated for European and Scandinavian countries collectively, they were significantly more effective in reducing bullying victimization outcomes than North American studies. However, the effect size in North American studies for bullying perpetration outcomes was not significantly different from the weighted mean for European and Scandinavian studies.

Effectiveness of Specific Anti-bullying Programs

Table 4 summarizes the effectiveness of specific anti-bullying programs in reducing school-bullying perpetration and victimization. Eight programs (i.e., Bully Proofing Your School, fairplayer.manual, KiVa, NoTrap!, OBPP, Second Step, Steps to Respect, and ViSC) could be studied in relation to bullying perpetration outcomes. The same programs, with the exception of the fairplayer.manual program, were studied in relation to bullying victimization outcomes. The effectiveness of these programs varied greatly. For both perpetration and victimization outcomes, we also report effect sizes for evaluations of the OBPP conducted in Norway ( n  = 5) and the USA ( n  = 6) separately. Overall, there were 12 evaluations of the OBPP included in our analysis, which includes one evaluation conducted in Malaysia.

In relation to school-bullying perpetration outcomes, overall the OBPP was the most effective intervention program. In addition, evaluations of the OBPP in Norway and in the USA were the most effective individually, in comparison with other included anti-bullying programs. The difference in the magnitude of OBPP evaluations conducted in Norway and in the USA was not statistically significant for school-bullying outcomes. Other programs were also significantly effective in reducing school-bullying perpetration behaviors, including KiVa, Second Step, and Steps to Respect, although their effect sizes were markedly lower in comparison to the OBPP. Positive effect sizes (i.e., OR > 1) were also observed for the BPYS and NoTrap! programs, but these effects were not statistically significant. Surprisingly, negative effects were found for two anti-bullying programs, the fairplayer manual and ViSC, although these effects were not statistically significant.

In relation to school-bullying victimization outcomes, NoTrap! was the most effective anti-bullying program, followed by the Bully Proofing Your School Program. Our analysis found that other anti-bullying programs were also significantly effective in reducing school-bullying victimization, including Steps to Respect and KiVa. The OBPP intervention program was the third most effective anti-bullying program for reducing victimization. Effect sizes for the OBPP varied significantly between evaluations conducted in Norway and evaluations conducted in the USA. Our analysis also found negative effects of the Second Step program in relation to victimization. Evaluations of the ViSC program also had a negative effect on bullying victimization, although this effect was not statistically significant.

Overall, the results of our meta-analysis are consistent with previous findings and show that school-based anti-bullying programs are effective in reducing bullying perpetration and victimization. Our meta-analysis included evaluations of anti-bullying programs from a wide range of countries and specific intervention programs, far more than in any previous meta-analysis (e.g., Cantone et al. 2015 ; Chalamandaris and Piette 2015 ; Evans et al. 2014 ; Jiménez-Barbero et al. 2012 ; Jiménez-Barbero et al. 2016 ). We conclude that school-based anti-bullying programs are effective in reducing both school-bullying perpetration and victimization globally and across different school-based programs.

Global Effectiveness

In Greece, where evaluations included in our meta-analysis were highly effective, school-bullying perpetration was reduced by approximately 40%. Evaluations conducted in the Norway, Italy, and the USA were effective in reducing bullying perpetration by approximately 21–25%. Anti-bullying programs implemented and evaluated in Italy were also very effective in reducing victimization in our meta-analysis, with the odds ratio effect size corresponding to an approximate reduction of 31%. Evaluations conducted in Spain and Norway reduced victimization by approximately 28% and 23%, respectively. Evaluations conducted in Finland, Germany, and the UK were also significantly effective in reducing victimization by approximately 8–12%.

We also identified regional differences in the effectiveness of anti-bullying programs. Specifically, intervention programs conducted in Europe significantly reduced bullying perpetration by around 13%, while interventions conducted in Scandinavian countries significantly reduced bullying perpetration by around 20%. Evaluations conducted in North America (i.e., the USA and Canada) significantly reduced bullying perpetration by around 21% and bullying victimization by around 11%. Comparatively, anti-bullying programs that were implemented and evaluated in Scandinavia and Europe reduced victimization by a larger percentage, 18% and 15% respectively. However, no clear pattern of statistically significant differences between regional effect sizes was identified in our analysis.

Limitations and Future Research

While the results of our further analysis in relation to the location of evaluations are interesting, the findings are limited in explaining why heterogeneity occurs between mean effect sizes. The current report highlights that anti-bullying programs are effective and are largely effective worldwide. The results are consistent with previous findings such as the recent UNESCO ( 2018 ) report on bullying. The majority of anti-bullying programs were evaluated in regions where the prevalence of bullying is already comparatively low, for example, Europe and North America. Our systematic review further highlights the lack of existing anti-bullying programs in areas where UNESCO report worryingly high levels of bullying, such as sub-Saharan Africa and the Middle East.

The lack of a clear pattern in relation to the regional effectiveness of anti-bullying programs may be explained by several factors. Firstly, there are a large number of potential confounding factors that could be influencing the overall results. When comparing the effectiveness of anti-bullying programs in a meta-analysis such as this, other moderators need to be considered. For example, previous analyses have found that anti-bullying programs are more effective with older participants (i.e., over age 11) than they are with participants aged 10 years old and younger (Farrington and Ttofi 2009 ). The relationships between participant age and overall effectiveness are not consistent, with prominent researchers disagreeing with this finding (e.g., Smith et al. 2012 ; Smith 2010 ).

Other potential confounding variables include the type of measurement, the specific intervention components, or the evaluation methodology used. Gaffney et al. ( 2019b ) showed that evaluations conducted using an age cohort design consistently resulted in the largest effect sizes. This may also serve to explain why the OBPP program and evaluations conducted in Norway/Scandinavia are found to produce larger effect sizes as this evaluation method is predominantly used to evaluate this program in Norwegian schools (Gaffney et al. 2019b ).

Previous research has indicated that there are cultural differences in bullying behaviors amongst adolescents (e.g., Smith et al. 2016 ). Therefore, an anti-bullying program that is designed to reduce these behaviors should reflect these differences. This is particularly evident when we observe the variations in effect sizes for the Olweus Bullying Prevention Program (OBPP; Olweus 1993a , b ). This program was originally designed and implemented in Norway, and it is therefore not surprising that the OBPP program was more effective in reducing both perpetration and victimization when evaluated in Norway, compared to evaluations in the USA (see Table 4 ). While the program was still significantly effective in the USA, the percentage decrease in school-bullying perpetration was 25% and in victimization was 11%. These figures are low in comparison to the decreases in bullying seen in Norwegian evaluations (35% perpetration; 29% victimization). These differences could be attributed to different evaluation methodologies (see Gaffney et al. 2019b ), but they could also reflect cultural and societal differences between youth in Norway and youth in the USA.

Moreover, when the OBPP was evaluated in six Malaysian secondary schools, with a sample size of approximately 3816 students, the program was not significantly effective in reducing school-bullying victimization (Yaakub et al. 2010 ; OR = 1.09, p  = 0.28). This may be a result of the different manifestations of school-bullying victimization in Eastern societies. As previously stated, researchers (e.g., Smith et al. 2016 ) have outlined that bullying manifests differently in Eastern and Western cultures. This may explain why in Malaysia, the OBPP was seemingly ineffective at reducing bullying victimization. It may be that the program itself was not tailored to the specific experiences and/or behaviors demonstrated by Malaysian students.

Future research is needed to better explore the potential factors that may explain heterogeneity observed between mean effect sizes of anti-bullying evaluations. For example, such research could incorporate the type of intervention implemented, the age of participants, the sample size, timeframe of measurement (i.e., bullying experienced in past 3, 6, 9 months), and the type of report (i.e., self-, peer-, or teacher-reported bullying).

Specific Interventions

We also explored the effectiveness of the four most widely disseminated anti-bullying programs that were included in our review (i.e., KiVA, NoTrap!, OBPP, ViSC). For the purpose of this analysis, we only included programs that had been evaluated on three or more independent occasions. The OBPP was the most effective in reducing school-bullying perpetration. Across 12 evaluations, the OBPP reduced bullying perpetration by approximately 26%. In relation to victimization outcomes, the NoTrap! program was the most effective, reducing victimization by around 37%. NoTrap! also reduced bullying perpetration by a considerable amount, approximately 22%, but this effect was not statistically significant. The KiVA program significantly reduced school-bullying perpetration by approximately 9% and school-bullying victimization by approximately 11%. The ViSC program was the only program to increase bullying perpetration (by roughly 4%) and bullying victimization (by roughly 4%), although these effects were not statistically significant. Again, these results may have been influenced by the particular evaluation methods used (see Weisburd et al. 2001 ).

Intervention Components

As Table 1 shows, the KiVA, NoTrap!, OBPP, and ViSC programs incorporated quite similar intervention components. Specifically, the KiVA, OBPP, and ViSC programs are very similar in practice, with the NoTrap! program being the most different of the four programs. As the effectiveness of these programs also varied, it may be possible, by exploring these different components, to better inform future research, practice, and policy decisions.

The Whole-School Approach

With respect to these programs, it is not surprising that three of the four adopted a “whole-school” approach (i.e., KiVA, the OBPP, and ViSC). This approach to anti-bullying programs was first introduced and implemented by Dan Olweus in Norway (i.e., OBPP, Olweus 1991 ), and it is undeniably the most common approach to bullying prevention. Other programs (i.e., KiVa or ViSC) have implemented this approach and applied a socio-ecological theoretical framework to explain any potential changes that occur as a result of the implementation. The whole-school approach to bullying prevention incorporates individuals involved in every aspect of students’ lives, for example, not only the students involved in bullying but also their peers, parents, teachers, and the wider community.

In relation to effectiveness, our meta-analysis suggests that the whole-school approach was not always the most effective. The OBPP was very effective in reducing both bullying perpetration and victimization, but the KiVa program was only marginally effective (approximately 9% and 11% decreases in perpetration and victimization respectively), and the ViSC program had an undesirable effect. Although the effect sizes for the ViSC program were not statistically significant, the odds ratios correspond to roughly a 4% increase in both bullying perpetration and victimization. Moreover, the non-whole-school program NoTrap! was the most effective intervention in reducing bullying victimization, with a decrease of 37% approximately. NoTrap! involved creating an online forum where trained students acted as moderators, responding to participants’ questions and concerns about bullying.

This suggests that, while school bullying may very well be a complex social peer-group phenomenon, the whole-school approach might not be effective for every individual student. This observation is consistent with previous research. For example, in the context of the KiVa anti-bullying program, Kaufman et al. ( 2018 ) recently characterized participants into different trajectories of victimization. This study found that high-trajectory (for victimization) participants (i.e., those who reported high levels of peer rejection, internalizing problems, and lower quality parent-child relationships) reported lesser decreases in victimization following the intervention, in comparison to participants in the decreasing and low/no victimization trajectories. The universal approach commonly includes school- and class-level components that focus on raising awareness about bullying-related issues. It may be the case that, by raising awareness, and focusing on highlighting bullying issues amongst students, the effect sizes may be influenced by a social desirability bias. This might explain why greater reductions are seen for whole-school programs for bullying perpetration in comparison to decreases for bullying victimization. To explore this result further, future research should aim to compare effect sizes based on participants’ self-reports to teacher- or peer-reports of bullying victimization and perpetration.

Peer Involvement

Gaffney, Ttofi, and Farrington ( 2019a ) previously found that the intervention component “work with peers” was associated with an increase in bullying victimization. However, this finding was not widely accepted by other researchers in the field who champion the peer-led approach to bullying prevention (e.g., Smith et al. 2012 ). In the four most widely disseminated programs, the peer group was involved in intervention activities in various ways. For example, the OBPP program involved actively working with participants to engage bystanders in order to encourage them to prevent, or respond accordingly to, bullying situations in their daily lives. Moreover, the OBPP involved in-class group exercises and discussions, as did the KiVA and ViSC programs. In comparison, the NoTrap! program is a peer-led program.

The NoTrap! program includes a peer-led online forum for participants to discuss bullying victimization experiences. It may be that the anonymity and protection of an online environment encourages participants to truly open up about bullying victimization, whereas in classroom settings, they may feel uncomfortable about disclosing their experiences. Previous research has shown that a number of factors, including trust and perceived privacy, can influence disclosure in online settings, in relation to sensitive issues (Joinson et al. 2010 ).

Furthermore, the overlap between offline and online bullying perpetration and victimization will increase amongst adolescents, as the Internet has become a part of our daily lives rather than an abstract place where different social norms apply (Rooney, Connolly, Hurley, Kirwan, and Power 2015 ). Previous studies have shown that the greatest risk factor for cyberbullying is school bullying (Baldry et al. 2015 ), and that the factors involved in both online and offline bullying regularly overlap (Tzani-Pepelasi et al. 2018 ). Therefore, it may be that moving from the classroom to online peer-led forums may be a way in which practitioners can improve intervention programs to better reduce bullying victimization. This may also be a practical and cost-effective method, to get students actively involved in anti-bullying work while also highlighting key issues.

Parent and Teacher Involvement

The NoTrap! program was the only program of these four widely disseminated programs that did not formally include teachers or parents in prevention activities. While this intervention focused on peer-led online forums (in conjunction with peer-led offline anti-bullying activities), the OBPP, KiVa, and ViSC programs each included the involvement of both parents and teachers. As previously stated, the involvement of teachers and parents is a key feature of the ecological, whole-school approach to anti-bullying programs. In both the KiVa and OBPP programs, parents received leaflets or letters at home that provided them with information about bullying and about the intervention program. Parents were also invited to information nights held at participating schools.

Similarly, the KiVA, OBPP, and ViSC programs trained teachers to implement the detailed anti-bullying curricula that were specific to the intervention programs. In the KiVA program, teachers were trained to implement either the “confronting approach” or the “no blame approach” when dealing with bullies. Both the KiVA and OBPP programs required teachers to engage with “hot-spot” supervision, which has been found to be an effective intervention component (Farrington and Ttofi 2009 ). Hot-spot supervision involves identifying locations within the school premises where bullying occurs frequently and increasing teacher presence in these areas. These elements are missing in the NoTrap! and ViSC programs, and this may be one potential reason why the KiVa and OBPP programs are more effective in reducing bullying perpetration.

Implications for Schools and Researchers

Our meta-analysis provides practitioners with useful insights into the effectiveness of anti-bullying interventions in a number of countries worldwide. Our results show that the effectiveness of school-based interventions for bullying perpetration and victimization varies between locations, and this should be something practitioners should take into account. Effectiveness also varies across different intervention programs, and particular components of anti-bullying programs have differential effectiveness in reducing bullying perpetration and victimization. The results of the present report lead to many recommendations and implications for teachers, schools, and practitioners who deal with school bullying amongst children and adolescents.

Recommendations for teachers and schools:

If implementing an existing anti-bullying program, practitioners should consider:

Previous evaluations of the effectiveness of anti-bullying programs in the same country, region, or culturally similar setting, as these factors may influence effectiveness.

The location and population for which the program was developed and evaluated initially, and whether this impacts previous measures of its effectiveness and its particular approach to tackling bullying.

A pre-intervention survey to explore the specific manifestations of bullying in their respective schools, to evaluate whether or not one particular program may address these issues better than another.

If implementing a new anti-bullying program, practitioners should consider:

Existing research reports and meta-analyses that assess specific intervention components and their effectiveness.

That whole-school anti-bullying campaigns can be effective, but they may not be the best strategy to combat bullying victimization; additional intervention components may also be needed.

That comprehensive anti-bullying programs should include intervention elements at multiple levels, including the school, class, parent, peer, and individual level. Targeted interventions are needed to help individual children that are particularly vulnerable to bullying victimization.

A pre-intervention survey to explore the specific manifestations of bullying in their respective schools to evaluate which components are the most effective, and practical, methods of reducing bullying victimization and perpetration.

That online forums, moderated by trained students, may be an efficient and cost-effective way to tackle bullying victimization.

That hot-spot supervision and specific strategies for dealing with bullying scenarios when it occurs are effective methods for preventing school-bullying perpetration and victimization.

Practitioners should take a number of factors into consideration when choosing an anti-bullying program. It is important to initially evaluate the nature, presence, and frequency of bullying in the relevant school. Bullying behaviors will not necessarily manifest in the same way in different countries, regions, communities, or schools, and thus may impact the effectiveness of any intervention program implemented. For example, the cross-national Health Behaviour in School-Aged Children (HBSC) study showed that greater income inequality predicted higher levels of bullying perpetration and victimization (Elgar et al. 2013 ). Therefore, implementing a program developed in a region with low-income inequality may not have the same level of effectiveness in an area of greater income inequality, as the causal roots of bullying are different.

The NoTrap! program was particularly effective, in comparison with other studies included in our meta-analysis, in reducing bullying victimization. This specific program was developed through several iterations and multiple evaluations in the same schools, but with different participants each year (Menesini et al. 2012 ; Palladino et al. 2012 , 2016 ). This suggests that schools should evaluate anti-bullying efforts on an ongoing basis and adapt programs according to the specific needs of the students, staff, and parents. Our meta-analysis did include several programs that adopted this approach, but they have not yet been repeatedly evaluated, and so are not included in the present report.

Practitioners should also consult the wealth of research and literature that exists in relation to effective anti-bullying programs. Research reports and meta-analyses of bullying intervention and prevention programs (e.g., Gaffney et al. 2019b ) can give practitioners a detailed overview about what works overall. Experts in the field have also produced a number of accessible handbooks and guides in relation to bullying issues (e.g., Patchin and Hinduja 2016 : Bullying today: bullet points and best practices ; Smith 2013 : Understanding School Bullying: Its Nature and Prevention Strategies ). Furthermore, journals such as this one, and interdisciplinary conferences such as the World Anti-Bullying Forum (next meeting in Dublin, June 2019), are key resources for teachers, school personnel, policy makers, and researchers to share and discuss important issues relating to bullying and its prevention.

Our results not only have important implications for teachers and schools. The results of our meta-analysis can have implications for researchers also. For example, 41 studies published between the years of 1983 and 2016 that reported the effectiveness of an anti-bullying program did not report enough statistical information. Frequently, authors included complicated advanced statistics to demonstrate the effectiveness of an anti-bullying program, but this information is not useful to meta-analysts. In addition, using advanced statistical methods may reduce the accessibility of evaluation studies for teachers and practitioners.

Thus, when reporting the evaluation data of an anti-bullying program, it is important to include basic descriptive statistics, such as the mean, standard deviation, and sample size. Alternatively, the frequency or prevalence of bullying perpetration and/or victimization should be reported as percentages to easily convert to odds ratio effect sizes. The second recommendation we would make is that more replication of scientific evaluations of anti-bullying programs is needed. Replication is essential in designing effective intervention programs. Yet our meta-analysis included 100 evaluations of approximately 65 anti-bullying programs, and only four of these programs had been evaluated three or more times.

We included roughly 65 different programs, as there was quite a bit of overlap in some of the intervention strategies included. For example, Trip et al. ( 2015 ) evaluated the ViSC program, yet also included elements of REBE. Therefore, the evaluated intervention is slightly different from the ViSC program evaluated by other researchers. The same can be said for the impact of implementation fidelity and quality on effect sizes. Previous studies in criminology, psychology, and other social sciences have found strong evidence to support the positive correlation between implementation quality and effect sizes for multiple outcomes (e.g., Farrington, Ttofi, and Losel 2016 ). Also, researchers could consider cost-benefit analysis of anti-bullying programs as a core aspect of evaluations. The few studies included in our meta-analysis that did conduct a cost-benefit analysis found desirable results (e.g., Bonell et al. 2015 ). Moreover, prominent researchers in the field have highlighted how using a metric to convert effect sizes to monetary values is a convincing way to communicate research findings to policy makers, government departments, and practitioners (Farrington and Koegl 2015 ).

Finally, the current paper is limited in its ability to inform on the effectiveness of intervention programs to reduce other forms of bullying, such as cyberbullying. Gaffney et al. ( 2019b ) recently reported that interventions are largely effective in reducing cyberbullying perpetration and victimization. However, more research needs to be conducted in this area as cyberbullying is a growing phenomenon amongst children and adolescents worldwide.

Concluding Remarks

This paper presents key findings and further analyses of a large-scale meta-analysis that explores the effectiveness of school-based anti-bullying programs (i.e., Gaffney et al. 2019b ). Overall, while school-bullying prevention programs are effective, there are significant differences between countries, regional areas, and existing intervention programs. Specifically, there is a lack of existing anti-bullying work in areas that report high levels of bullying behaviors and repeated evaluations of existing programs. We make several recommendations for practitioners and researchers and suggest that future research can be conducted to better understand what works in anti-bullying programming.

Ahtola, A., Haataja, A., Kärnä, A., Poskiparta, E., & Salmivalli, C. (2012). For children only? Effects of the KiVa antibullying program on teachers. Teaching and Teacher Education, 28 , 851–859. https://doi.org/10.1016/j.tate.2012.03.006 .

Article   Google Scholar  

Ahtola, A., Haataja, A., Kärnä, A., Poskiparta, E., & Salmivalli, C. (2013). Implementation of anti-bullying lessons in primary classrooms: how important is head teacher support? Educational Research, 55 (4), 376–392. https://doi.org/10.1080/00131881.2013.844941 .

Alsaker, F. D., & Valkanover, S. (2001). Early diagnosis and prevention of victimization in kindergarten. In J. Juvonen & S. Graham (Eds.), Peer harassment in school (pp. 175–195). New York: Guilford.

Google Scholar  

Arsenault, L., Bowes, L., & Shakoor, S. (2010). Bullying victimization in youths and mental health problems: ‘Much ado about nothing’? Psychological Medicine, 40 (5), 717–729.

Atria, M., Strohmeier, D., & Spiel, C. (2007). Viennese Social Competence (ViSC) training for pupils: program and evaluation. In J. E. Zins, M. J. Elias, & C. A. Maher (Eds.), Bullying, victimization, and peer harassment: a handbook of prevention and intervention (pp. 179–197). New York: Haworth Press.

Baldry, A. C., Farrington, D. P., & Sorrentino, A. (2015). “Am I at risk of cyberbullying”? A narrative review and conceptual framework for research on risk of cyberbullying and cybervictimization: the risk and needs assessment approach. Aggression and Violent Behavior, 23 , 36–51. https://doi.org/10.1016/j.avb.2015.05.014 .

Bandura, A. (1977). Social learning theory . Engleworth Cliffs: Prentice Hall.

Bauman, S. (2013). Why it matters. In S. Bauman, D. Cross, & J. Walker (Eds.), Principles of cyberbullying research: definitions, measures, and methodology (pp. 23–26). New York: Routledge.

Betts, L. R. (2016). Cyberbullying: approaches, consequences, and interventions. In J. Binder (Ed.), Palgrave studies in Cyberpsychology . London: Palgrave Macmillan.

Bonell, C., Fletcher, A., Fitzgerald-Yau, N., Hale, D., Allen, E., Elbourne, D., Jones, R., Bond, L., Wiggins, M., Miners, A., Legood, A., Scott, S., Christie, D., & Viner, R. (2015). Initiating change locally in bullying and aggression through the school environment (INCLUSIVE): a pilot randomised controlled trial. Health Technology Assessment, 19 (53), 1–110.

Bronfenbrenner, U. (1979). The ecology of human development: experiments by nature and design . Cambridge: Harvard University Press.

Cantone, E., Piras, A.P., Vellante, M., Preti, A., Daníelsdóttir, S., D’Aloja, E., … & Bhugra, D. (2015). Interventions on bullying and cyberbullying in schools: a systematic review. Clinical Practice and Epidemiology in Mental Health, 11 (Suppl 1 M4), 58–76. https://doi.org/10.2174/174501791511010058

Centers for Disease Control and Prevention. (2014). Bullying surveillance among school-aged children: uniform definitions and recommended data elements . Washington, DC: Centers for Disease Control and Prevention (CDC).

Chalamandaris, A., & Piette, D. (2015). School-based anti-bullying interventions: systematic review of the methodology to assess their effectiveness. Aggression and Violent Behavior, 24 , 131–174. https://doi.org/10.1016/j.avb.2015.04.004 .

Chester, K. L., Callaghan, M., Cosma, A., Donnelly, P., Craig, W., Walsh, S., & Molcho, M. (2015). Cross-national time trends in bullying victimization in 33 countries among children aged 11, 13, and 15 from 2002 to 2010. European Journal of Public Health, 25 (Suppl 2), 61–64. https://doi.org/10.1093/eurpub/ckv029 .

Article   PubMed   Google Scholar  

da Silva, J. L., de Oliveira, W. A., Braga, I. F., Farias, M. S., de Silva Lizzi, E. A., et al. (2016). The effects of a skill-based intervention for victims of bullying in Brazil. International Journal of Environmental Research and Public Health, 13 , 1042. https://doi.org/10.3390/ijerph13111042 .

Article   PubMed Central   Google Scholar  

Donner, A., Piaggio, G., & Villar, J. (2001). Statistical methods for the meta-analysis of cluster randomized trials. Statistical Methods in Medical Research, 10 , 325–338.

Due, P., Holstein, B. E., Lynch, J., Diderichsen, F., Nic Gabhain, S., Scheidt, P., Currie, C., & The Health Behaviour in School-aged Children Bullying working group. (2005). Bullying and symptoms among school-aged children: international comparative cross-sectional study in 28 countries. European Journal of Public Health, 15 (2), 128–132. https://doi.org/10.1093/eurpub/cki105 .

Easterbrook, P. J., Gopalan, R., Berlin, J. A., & Matthews, D. R. (1991). Publication bias in clinical research. The Lancet, 337 (8746), 867–872. https://doi.org/10.1016/0140-6736(91)90201-Y .

Elgar, F. J., Craig, W., Boyce, W., Morgan, A., & Vella-Zarb, R. (2009). Income inequality and school bullying: multilevel study of adolescents in 37 countries. Journal of Adolescent Health, 45 (4), 351–359.

Elgar, F. J., Pickett, K. E., Pickett, W., Craig, W., Molcho, M., Hurrelmann, K., & Lenzi, M. (2013). School bullying, homicide and income inequality: a cross-national pooled time series analysis. International Journal of Public Health, 58 (2), 237–245.

Evans, C. B. R., Fraser, M. W., & Cotter, K. L. (2014). The effectiveness of school-based bullying prevention programs: a systematic review. Aggression and Violent Behavior, 19 (5), 532–544. https://doi.org/10.1016/j.avb.2014.07.004 .

Farrington, D. P. (1993). Understanding and preventing bullying. Crime and Justice, 17 , 381–458.

Farrington, D. P., & Ttofi, M. M. (2009). School-based programs to reduce bullying and victimization. Campbell Systematic Reviews, 6 , 1–148. https://doi.org/10.4073/csr.2009.6 .

Farrington, D. P., & Welsh, B. C. (2013). Measuring effect size in meta-analysis, with special reference to area-based crime prevention programs and the effects of close-circuit television on crime. In A. A. Kuhn, C. Schawarzenegger, P. Margot, A. Donatsch, M. Aebi, & D. Jositsch (Eds.), Criminology, criminal policy and criminal law from an international perspective (pp. 75–89). Berne: Stampfli.

Farrington, D. P., & Koegl, C. J. (2015). Monetary benefits and costs of the Stop Now and Plan program for boys aged 6 - 11, based on the prevention of later offending. Journal of Quantitative Criminology, 31 (2), 263–287. https://doi.org/10.1007/s10940-014-9240-7 .

Farrington, D. P., Ttofi, M. M., & Lösel, F. A. (2016). Developmental and social prevention. In D. Weisburd, D. P. Farrington, & C. Gill (Eds.), What works in crime prevention and rehabilitation: lessons from systematic reviews (pp. 15–75). New York: Springer.

Finn, K. O’K. (2009). An evaluation of the Olweus Bullying Prevention Program . Retrieved from ProQuest Dissertations Publishing (3343406).

Fry, D., Fang, X., Elliott, S., Casey, T., Zheng, X., Li, J., Florian, L., & McCluskey, G. (2018). The relationships between violence in childhood and educational outcomes: a global systematic review and meta-analysis. Child Abuse and Neglect, 75 , 6–28. https://doi.org/10.1016/j.chiabu.2017.06.021 .

Gaffney, H., Ttofi, M. M., & Farrington, D. P. (2019a). Evaluating the effectiveness of school-bullying prevention programs: an updated meta-analytical review. Aggression and Violent Behavior . https://doi.org/10.1016/j.avb.2018.07.001 .

Gaffney, H., Farrington, D. P., Espelage, D. L., & Ttofi, M. M. (2019b). Are cyberbullying intervention and prevention programs effective?A systematic and meta-analytical review. Aggression and Violent Behavior . https://doi.org/10.1016/j.avb.2018.07.002 .

Garandeau, C. F., Lee, L. A., & Salmivalli, C. (2014a). Differential effects of the KiVa anti-bullying program on popular and unpopular bullies. Journal of Applied Developmental Psychology, 35 (1), 44–50. https://doi.org/10.1016/j.appdev.2013.10.004 .

Garandeau, C. F., Poskiparta, E., & Salmivalli, C. (2014b). Tackling acute cases of school bullying in the KiVa anti-bullying program: a comparison of two approaches. Journal of Abnormal Child Psychology, 42 , 981–991. https://doi.org/10.1007/s10802-014-9861-1 .

Gollwitzer, M., Eisenbach, K., Atria, M., Strohmeier, D., & Banse, R. (2006). Evaluation of aggression-reducing effects of the ‘Viennese Social Competence Training. Swiss Journal of Psychology, 65 , 125–135.

Gradinger, P., Yanagida, T., Strohmeier, D., & Spiel, C. (2015). Prevention of cyberbullying and cyber victimization: evaluation of the ViSC Social Competence program. Journal of School Violence, 14 (1), 87–110. https://doi.org/10.1080/15388220.2014.96323 .

Haataja, A., Voeten, M., Boulton, A. J., Poskiparta, E., & Salmivalli, C. (2014). The KiVa antibullying curriculum and outcome: does fidelity matter? Journal of School Psychology, 52 , 479–492. https://doi.org/10.1016/j.jsp.2014.07.001 .

Hawker, D. S. J., & Boulton, M. J. (2000). Twenty years’ research on peer victimization and psychosocial maladjustment: a meta-analytic review of cross-sectional studies. Journal of Child Psychology and Psychiatry, 41 , 441–455.

Hinduja, S., & Patchin, J. W. (2010). Bullying, cyberbullying, and suicide. Archives of Suicide Research, 14 (3), 206–221. https://doi.org/10.1080/13811118.2010..494133 .

Holt, M. K., Vivolo-Kantor, A. M., Polanin, J. R., Holland, K. M., DeGue, S., Matjasko, J. L., Wolfe, M., & Reid, G. (2015). Bullying and suicidal ideation and behavior: a meta-analysis. Pediatrics, 135 (2), e496–e509. https://doi.org/10.1542/peds.2014-1864 .

Article   PubMed   PubMed Central   Google Scholar  

Hutchings, J., & Clarkson, S. (2015). Introducing and piloting the KiVa bullying prevention programme in the UK. Educational and Child Psychology, 32 (1), 49–61.

Jiménez-Barbero, J. A., Ruiz Hernández, J. A., Llor-Esteban, B., & Pérez-García, M. (2012). Effectiveness of antibullying school programmes: a systematic review by evidence levels. Children and Youth Services Review, 34 (9), 1646–1658. https://doi.org/10.1016/j.childyouth.2012.04.025 .

Jiménez-Barbero, J. A., Ruiz-Hernández, J. A., Llor-Zaragoza, L., Pérez-García, M., & Llor-Esteban, B. (2016). Effectiveness of anti-bullying school programs: a meta-analysis. Children and Youth Services Review, 61 , 165–175. https://doi.org/10.1016/j.childyouth.2015.12.015 .

Joinson, A. N., Reips, U.-D., Buchanan, T., & Paine, C. B. (2010). Privacy, trust, and self-disclosure online. Human-Computer Interaction, 25 (1), 1–24. https://doi.org/10.1080/0737002090358662 .

Ju, Y., Shuqiong, W., & Wenxin, Z. (2009). Intervention research on school bullying in primary schools. Frontiers of Education in China, 4 , 111–122. https://doi.org/10.1007/s11516-009-0007-0 .

Kaljee, L., Zhang, L., Langhaug, L., Munjile, K., Tembo, S., Menon, A., Stanton, B., Li, X., & Malungo, J. (2017). A randomized controlled trial for the teachers’ diploma programme on psychosocial care, support and protection in Zambian government primary schools. Psychology, Health, and Medicine, 22 (4), 381–392. https://doi.org/10.1080/13548503.2016.1153682 .

Kärnä, A., Voeten, M., Little, T. D., Alanen, E., Poskiparta, E., & Salmivalli, C. (2011a). Going to scale: a nonrandomized nationwide trial of the KiVa antibullying program for grades 1–9. Journal of Consulting and Clinical Psychology, 79 (6), 796–805. https://doi.org/10.1037/a0025740 .

Kärnä, A., Voeten, M., Little, T. D., Alanen, E., Poskiparta, E., & Salmivalli, C. (2011b). A large-scale evaluation of the KiVa antibullying program: grades 4–6. Child Development, 82 (1), 311–330. https://doi.org/10.1111/j.1467-8624.2010.01.557.x .

Kärnä, A., Voeten, M., Little, T. D., Alanen, E., Poskiparta, E., & Salmivalli, C. (2013). Effectiveness of the KiVa anti-bullying program: grades 1–3 and 7–9. Journal of Educational Psychology, 105 (2), 535–551. https://doi.org/10.1037/a0030417 .

Kaufman, T. M. L., Kretschmer, T., Huitsing, G., & Veenstra, R. (2018). Why does a universal anti-bullying program not help all children? Explaining persistent victimization during an intervention. Prevention Science., 19 , 822–832. https://doi.org/10.1007/s11121-018-0906-5 .

Kimber, B., Sandell, R., & Bremberg, S. (2008). Social and emotional training in Swedish classrooms for the promotion of mental health: results from an effectiveness study in Sweden. Health Promotion International, 23 (2), 134–143. https://doi.org/10.1093/heapro/dam046 .

Klomek, A. B., Sourander, A., & Gould, M. (2010). The association of suicide and bullying in childhood to young adulthood: a review of cross-sectional and longitudinal research findings. Canadian Journal of Psychiatry, 55 (5), 282–288.

Kowalski, R. M., Toth, A., & Morgan, M. (2018). Bullying and cyberbullying in adulthood and the workplace. Journal of Social Psychology, 158 (1), 64–81. https://doi.org/10.1080/00224545.2017.1302402 .

Limber, S. P., Olweus, D., Wang, W., Masiello, M., & Breivik, K. (2018). Evaluation of the Olweus Bullying Prevention Program: a large scale study of U.S. students in grades 3–11. Journal of School Psychology, 69 , 56–72. https://doi.org/10.1016/j.jsp.2018.04.004 .

Losey, R.A. (2009). An evaluation of the Olweus Bullying Prevention Program’s effectiveness in a high school setting. Unpublished doctoral dissertation, University of Cincinnati, Ohio, U.S.A.

Masiello, M. G., & Schroeder, D. (2013). A public health approach to bullying prevention . Washington, DC: APHA Press.

McAuley, L., Tugwell, P., & Moher, D. (2000). Does the inclusion of grey literature influence estimates of intervention effectiveness reported in meta-analysis? The Lancet, 356 (9237), 1228–1231.

Menesini, E., Nocentini, A., & Palladino, B. E. (2012). Empowering students against bullying and cyberbullying: evaluation of an Italian peer-led model. International Journal of Conflict and Violence, 6 (2), 314–320.

Meyer, N., & Lesch, E. (2000). An analysis of the limitations of a behavioural programme for bullying boys from a sub-economic environment. Southern African Journal of Child and Adolescent Mental Health, 12 (1), 59–69.

Modecki, K. L., Minchin, J., Harbaugh, A. G., Guerra, N. G., & Runions, K. C. (2014). Bullying prevalence across contexts: a meta-analysis measuring cyber and traditional bullying. Journal of Adolescent Health, 55 , 602–611. https://doi.org/10.1016/j.jadohealth.2014.06.007 .

Nocentini, A., & Menesini, E. (2016). KiVa antibullying program in Italy: evidence of effectiveness in a randomized control trial. Prevention Science, 17 (8), 1012–1023. https://doi.org/10.1007/s11121-016-0690-z .

Noland, B. (2011). Effects of the KiVa anti-bullying program on adolescents’ perceptions of peers, depression, and anxiety. Unpublished doctoral dissertation, Kansas: University of Kansas.

O’Moore, A. M., & Minton, S. J. (2004). Ireland: the Donegal primary school antibullying project. In P. K. Smith, D. Pepler, & K. Rigby (Eds.), Bullying in schools: how successful can interventions be? (pp. 275–288). Cambridge: Cambridge University Press.

Chapter   Google Scholar  

Olweus, D. (1992). Bullying among school children: intervention and prevention. In R. D. Peters, R. J. McMahon, & V. L. Quinsey (Eds.), Aggression and violence throughout the lifespan (pp. 100–125). London: Sage.

Olweus, D. (1993a). Bully/victim problems among school children: long-term consequences and an effective intervention program. In S. Hodgins (Ed.), Mental disorder and crime (pp. 317–349). Thousand Oaks: Sage.

Olweus, D. (1993b). Bullying at school: what we know and what we can do . Oxford: Blackwell.

Olweus, D., & Limber, S. (2010). Bullying in school: evaluation and dissemination of the Olweus Bullying Prevention Program. American Journal of Orthopsychiatry, 80 (1), 124–134. https://doi.org/10.1111/j.1939-0025.2010.01015.x .

Olweus, D., Limber, S., & Mihalic, S. (1999). Blueprints for violence prevention, vol 9. The Bullying Prevention Program . Boulder: Institute of Behavioral Science, University of Colorado.

Olweus, D., Limber, S. P., Flerx, V., Mullin, N., Riese, J., & Snyder, M. (2007). Olweus Bullying Prevention Program: schoolwide guide . Center City: Hazelden.

Palladino, B. E., Nocentini, A., & Menesini, E. (2012). Online and offline peer led models against bullying and cyberbullying. Psicothema, 24 (4), 634–639.

PubMed   Google Scholar  

Palladino, B. E., Nocentini, A., & Menesini, E. (2016). Evidence-based intervention against bullying and cyberbullying: evaluation of the NoTrap! program in two independent trials. Aggressive Behavior, 42 (2), 194–206. https://doi.org/10.1002/ab.21636 .

Patchin, J., & Hinduja, S. (2016). Bullying today: bullet points and best practices . Thousand Oaks: Corwin Press.

Purugulla, V. (2011). Impact of the Olweus Bullying Prevention Program on a middle school environment. Unpublished doctoral dissertation, Piedmont College. Retrieved from ProQuest (3508170).

Rican, P., Ondrova, K., & Svatos, J. (1996). The effect of a short, intensive intervention upon bullying in four classes in a Czech town. Annals of the New York Academy of Sciences, 794 , 399–400.

Rooney, B., Connolly, I., Hurley, O., Kirwan, G., & Power, A. (2015). Social media and networking behaviour. In A. Atrill (Ed.), Cyberpsychology, pp. 88–101.

Sainio, M., Veenstra, R., Huitsing, G., & Salmivalli, C. (2012). Same- and other-sex victimization: are the risk factors similar? Aggressive Behavior, 38 , 422–455. https://doi.org/10.1002/ab.21445 .

Salmivalli, C. (2010). Bullying and the peer group: a review. Aggression and Violent Behavior, 15 (2), 112–120. https://doi.org/10.1016/j.avb.2015.10.001 .

Salmivalli, C., Kärnä, A., & Poskiparta, E. (2012). Counteracting bullying in Finland: the KiVa program and its effects on different forms of being bullied. International Journal of Behavioral Development, 35 (5), 405–411. https://doi.org/10.1177/0165025411407457 .

Sapouna, M., Wolke, D., Vannini, N., Watson, S., Woods, S., Schneider, W., Enz, S., Hall, L., Paiva, A., André, E., Dautenhahn, K., & Aylett, R. (2010). Virtual learning intervention to reduce bullying victimization in primary school: a controlled trial. Journal of Child Psychology and Psychiatry, 51 (1), 104–112. https://doi.org/10.1111/j.1469-7610.2009.02137.x .

Smith, P. K. (2010). Cyberbullying: the European perspective. In J. Mora-Merchán & T. Jäger (Eds.), Cyberbullying: a cross-national comparison (pp. 7–19). Landau: Empirische Pädagogik.

Smith, P. K. (2013). Understanding school bullying: its nature and prevention . London: Sage Publications.

Smith, P. K., Salmivalli, C., & Cowie, H. (2012). Effectiveness of school-based programs to reduce bullying: a commentary. Journal of Experimental Criminology, 8 , 433–441. https://doi.org/10.1007/s11292-012-9142-3 .

Smith, P. K., Kwak, K., & Toda, Y. (2016). School bullying in different cultures: Eastern and Western perspectives . Cambridge: Cambridge University Press.

Book   Google Scholar  

Solomontos-Kountouri, O., Gradinger, P., Yanagida, T., & Strohmeier, D. (2016). The implementation and evaluation of the ViSC program in Cyprus: challenges of cross-national dissemination and evaluation results. European Journal of Development Psychology, 13 (6), 737–755. https://doi.org/10.1080/17405629.2015.1136618 .

Swearer, S. M., & Espelage, D. L. (2004). Introduction: a socio-ecological framework of bullying among youth. In D. L. Espealge & S. M. Swearer (Eds.), Bullying in American schools: a social-ecological perspective on prevention and intervention (pp. 1–12). Mahwah: Lawrence Erlbaum Associates.

Toda, Y. (2016). Bullying ( ijime ) and related problems in Japan: history and research. In P. K. Smith, K. Kwak, & Y. Toda (Eds.), School bullying in different cultures: Eastern and Western perspectives (pp. 73–92). Cambridge: Cambridge University Press.

Trip, S., Bora, C., Sipos-Gug, S., Tocai, I., Gradinger, P., Yanagida, T., & Strohmeier, D. (2015). Bullying prevention in schools by targeting cognitions, emotions, and behavior: evaluating the effectiveness of the REBE-ViSC program. Journal of Counselling Psychology, 62 (4), 732–740. https://doi.org/10.1037/cou0000084 .

Ttofi, M. M. (2015). Adolescent bullying linked to depression in early adulthood: evidence supports early intervention. British Medical Journal, 350 , h2694.

Ttofi, M. M., Farrington, D. P., Lösel, F., & Loeber, R. (2011a). Do the victims of school bullies tend to become depressed later in life? A systematic review and meta-analysis of longitudinal studies. Journal of Aggression, Conflict, and Peace Research, 3 , 63–73.

Ttofi, M. M., Farrington, D. P., Lösel, F., & Loeber, R. (2011b). The predictive efficiency of school bullying versus later offending: a systematic/meta-analytic review of longitudinal studies. Criminal Behaviour and Mental Health, 21 , 80–89.

Ttofi, M. M., Farrington, D. P., & Lösel, F. (2012). School bullying as a predictor of violence later in life: a systematic review and meta-analysis of prospective longitudinal studies. Aggression and Violent Behavior, 17 , 405–418.

Ttofi, M. M., Farrington, D. P., Lösel, F., Crago, R. V., & Theodorakis, N. (2016). School bullying and drug use later in life: a meta-analytic investigation. School Psychology Quarterly, 31 (1), 8–27.

Tzani-Pepelasi, C., Iaonnou, M., Synnott, J., & Ashton, S.-A. (2018). Comparing factors related to school-bullying and cyber-bullying. Crime Psychology Review, 4 (1), 1–25. https://doi.org/10.1080/23744006.2018.1474029 .

United Nations Educational, Scientific, and Cultural Organisation. (2018). School violence and bullying: global status and trends, drivers and consequences . Paris: UNESCO.

Valdebenito, S., Ttofi, M., & Eisner, M. (2015). Prevalence rates of drug use among school bullies and victims: a systematic review and meta-analysis of cross-sectional studies. Aggression and Violent Behavior, 23 , 137–146. https://doi.org/10.1016/j.avb.2015.05.004 .

Valdebenito, S., Ttofi, M. M., Eisner, M., & Gaffney, H. (2017). Weapon carrying in and out of school among pure bullies, pure victims and bully-victims: a systematic review and meta-analysis of cross-sectional and longitudinal studies. Aggression and Violent Behavior, 33 , 62–77.

Weisburd, D., Lum, C. M., & Petrosino, A. (2001). Does research design affect study outcomes in criminal justice? Annals of the American Academy of Political and Social Science, 578 , 50–70. http://www.jstor.org/stable/1049867 .

Williford, A., Boulton, A., Noland, B., Little, T. D., Kärnä, A., & Salmivalli, C. (2012). Effects of KiVa anti-bullying program on adolescents’ depression, anxiety, and perception of peers. Journal of Abnormal Child Psychology, 40 , 289–300. https://doi.org/10.1007/s10802-011-9551-1 .

Williford, A., Elledge, L. C., Boulton, A. J., DePaolis, K. J., Little, T. D., & Salmivalli, C. (2013). Effects of the KiVa anti-bullying program on cyberbullying and cybervictimization frequency among Finnish youth. Journal of Clinical Child and Adolescent Psychology, 42 (6), 820–833. https://doi.org/10.1080/15374416.2013.787623 .

Wong, D. S. W., Cheng, C. H. K., Ngan, R. M. H., & Ma, S. K. (2011). Program effectiveness of a restorative whole-school approach for tackling school bullying in Hong Kong. International Journal of Offender Therapy and Comparative Criminology, 55 (6), 846–862. https://doi.org/10.1177/0306624X10374638 .

Yaakub, N. F., Haron, F., & Leong, G. C. (2010). Examining the efficacy of the Olweus prevention programme in reducing bullying: the Malaysian experience. Procedia – Social and Behavioral Sciences, 5 , 595–598. https://doi.org/10.1016/j.sbspro.2010.07.148 .

Yanagida, T., Strohmeier, D., & Spiel, C. (2016). Dynamic change of aggressive behavior and victimization among adolescents: effectiveness of the ViSC program. Journal of Clinical Child & Adolescent Psychology . https://doi.org/10.1080/15374416.2016.1233498 .

Yang, A., & Salmivalli, C. (2014). Effectiveness of the KiVa antibullying programme on bully-victims, bullies and victims. Educational Research, 57 (1), 80–90.

Zych, I., Ortega-Ruiz, R., & del Rey, R. (2015). Systematic review of theoretical studies on bullying and cyberbullying: facts, knowledge, prevention, and intervention. Aggression and Violent Behavior, 23 , 1–21. https://doi.org/10.1016/j.avb.2015.10.001 .

Download references

Author information

Authors and affiliations.

Institute of Criminology, University of Cambridge, Sidgwick Avenue, Cambridge, CB3 9DA, UK

Hannah Gaffney, David P. Farrington & Maria M. Ttofi

You can also search for this author in PubMed   Google Scholar

Corresponding author

Correspondence to Hannah Gaffney .

Rights and permissions

Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Reprints and permissions

About this article

Gaffney, H., Farrington, D.P. & Ttofi, M.M. Examining the Effectiveness of School-Bullying Intervention Programs Globally: a Meta-analysis. Int Journal of Bullying Prevention 1 , 14–31 (2019). https://doi.org/10.1007/s42380-019-0007-4

Download citation

Published : 21 February 2019

Issue Date : 01 March 2019

DOI : https://doi.org/10.1007/s42380-019-0007-4

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

  • School-bullying
  • Anti-bullying
  • Find a journal
  • Publish with us
  • Track your research

Bullying Essay for Students and Children

500+ words essay on bullying.

Bullying refers to aggressive behavior so as to dominate the other person. It refers to the coercion of power over others so that one individual can dominate others. It is an act that is not one time, instead, it keeps on repeating over frequent intervals.  The person(s) who bullies others can be termed as bullies, who make fun of others due to several reasons. Bullying is a result of someone’s perception of the imbalance of power.

bullying essay

Types of bullying :

There can be various types of bullying, like:

  • Physical bullying:  When the bullies try to physically hurt or torture someone, or even touch someone without his/her consent can be termed as physical bullying .
  • Verbal bullying:  It is when a person taunts or teases the other person.
  • Psychological bullying:  When a person or group of persons gossip about another person or exclude them from being part of the group, can be termed as psychological bullying.
  • Cyber bullying:  When bullies make use of social media to insult or hurt someone. They may make comments bad and degrading comments on the person at the public forum and hence make the other person feel embarrassed. Bullies may also post personal information, pictures or videos on social media to deteriorate some one’s public image.

Read Essay on Cyber Bullying

Bullying can happen at any stage of life, such as school bullying, College bullying, Workplace bullying, Public Place bullying, etc. Many times not only the other persons but the family members or parents also unknowingly bully an individual by making constant discouraging remarks. Hence the victim gradually starts losing his/her self-esteem, and may also suffer from psychological disorders.

A UNESCO report says that 32% of students are bullied at schools worldwide. In our country as well, bullying is becoming quite common. Instead, bullying is becoming a major problem worldwide. It has been noted that physical bullying is prevalent amongst boys and psychological bullying is prevalent amongst girls.

Prevention strategies:

In the case of school bullying, parents and teachers can play an important role. They should try and notice the early symptoms of children/students such as behavioral change, lack of self-esteem, concentration deficit, etc. Early recognition of symptoms, prompt action and timely counseling can reduce the after-effects of bullying on the victim.

Get the huge list of more than 500 Essay Topics and Ideas

Anti-bullying laws :

One should be aware of the anti-bullying laws in India. Awareness about such laws may also create discouragement to the act of bullying amongst children and youngsters. Some information about anti-bullying laws is as follows:

  • Laws in School: To put a notice on the notice board that if any student is found bullying other students then he/she can be rusticated. A committee should be formed which can have representatives from school, parents, legal, etc.
  • Laws in Colleges: The government of India, in order to prevent ragging , has created guideline called “UGC regulations on curbing the menace of ragging in Higher Education Institutions,2009”.
  • Cyber Bullying Laws: The victim can file a complaint under the Indian Penal Code .

Conclusion:

It is the duty of the parents to constantly preach their children about not bullying anyone and that it is wrong. Hence, if we, as a society need to grow and develop then we have to collectively work towards discouraging the act of bullying and hence make our children feel secure.

Customize your course in 30 seconds

Which class are you in.

tutor

  • Travelling Essay
  • Picnic Essay
  • Our Country Essay
  • My Parents Essay
  • Essay on Favourite Personality
  • Essay on Memorable Day of My Life
  • Essay on Knowledge is Power
  • Essay on Gurpurab
  • Essay on My Favourite Season
  • Essay on Types of Sports

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Download the App

Google Play

Prevention of Bullying in Schools

Introduction.

Peer victimization, also known as bullying, comprises commonly recurring, unsolicited, hostile behavior among school-aged children involving a real or perceived power imbalance. Bullying that takes place in educational settings is a relevant and critical global issue, and while it affects all children regardless of culture, ethnicity, gender, or race, some groups may experience various disparities and increased exposure to bullying. Parents, educational institutions, and government entities alike have recognized the harmful, long-term effects of bullying in all its forms. Although the scenarios and unique circumstances of affected students may vary, it is possible for institutions to take a number of general actions to prevent or deal with bullying.

Definition of Bullying

In the 1980s, prominent researchers on the topic of bullying in education developed a definition that scholars have since generally recognized. According to this definition, “A student is being bullied or victimized when he or she is exposed, repeatedly and over time, to negative actions on the part of one or more other students” (Olweus & Limber, 2010, p. 124). These “negative actions” can vary significantly, ranging from physical contact to verbal abuse or emotional exclusion.

However, the key characteristics of bullying are that the behavior is intentional, repeated, and negative towards the victims who are the target of the bullying and who are also commonly helpless to defend themselves. Aggressive actions and even harm are likely to be an ongoing occurrence in an interpersonal relationship that suffers from a lack of “actual or perceived balance of power or strength” (Olweus & Limber, 2010, p. 125).

These traits are essential to defining the elements of bullying in the social behavior of children. Consistent and repeated negative behavior leads to bullying interactions and patterns, which this paper seeks to address.

Today’s educational institutions and entities actively recognize bullying as a behavior pattern that has severe implications but can also be prevented. The debate amongst educational scholars has focused on the impact of the school environment on bullying, including whether certain policies foster or buffer such behaviors amongst youth. Research has examined various factors ranging from budgets to class sizes and demographic distributions. Over the course of identifying the psychology and patterns behind bullying, scholars have studied broader constructs such as school policy, instructor attitudes, and peer interaction as indicators of potentially problematic behaviors (Swearer, Espelage, Vaillancourt & Hymel, 2010).

Cyberbullying

Developing technological capabilities and widening the availability of internet access have lent themselves to the rise of cyberbullying. The number of adolescents actively using internet-based services continues to rapidly increase; an estimated 66% of teens have access to the internet from the privacy of their bedrooms (Tokunaga, 2010). Cyberbullying is a general term that describes bullying behaviors, such as online harassment, that take place in the digital realm. This virtual form of bullying, which offers the possibility of anonymity, is unique in the protection it may potentially provide the bully. Furthermore, unlike the physical spheres of traditional bullying, cyberspace lacks the strict supervision of parents and teachers that may be present to some extent in real-world peer interactions.

Although popular media and tragic incidents have exposed the dangers and various issues related to adolescent interaction with the World Wide Web, the popularity of this technological communication medium continues to grow without adequate safety measures in place. Students face cyberstalking and public abuse that exerts negative psychological effects on their mental health (Tokunaga, 2010).

The discussion of cyberbullying is becoming ever more relevant as a significant portion of peer social interaction is transitioning online, hosted by various social media platforms. Schools lack online authority over children, highlighting the importance of anti-bullying strategies that will encourage positive behavior and establish social foundations in lieu of disciplinary punishment that cannot be enforced outside school hours.

Example of Bullying

Those affected by bullying are usually members of a group that is marginalized by some unique characteristic that makes them stand out. This will be analyzed more deeply later in the report, but it is vital to describe an example of the bullying process in a commonly affected group. As bullying is generating headlines with anecdotal evidence of extreme abuse and subsequent consequences, the negative impact on self-worth is growing, a reflection of humiliating experiences and students feeling unsafe.

One marginalized group, highly vulnerable to bullying, includes students with learning disabilities and autism, who have particular needs that peers, teachers, and communities should consider. Statistics indicate that 63% of victimized students are identified as having Autism Spectrum Disorder (ASD) and are bullied more often than students with other disabilities (Espelage & Swearer, 2008).

The nature of ASD creates social difficulties for students, hindering their understanding of the emotions, intentions, social cues, and nonliteral speech of their peers. Researchers are unclear as to whether ASD students perceive bullying as others do. Nevertheless, observation dictates that ASD students do experience higher rates of this negative behavior. Their difficulties in social interaction and communication may also hinder youth with ASD from reporting incidents.

In addition, issues affecting abstract thought and generalization can cause ASD students to inadequately relate the victimization experience to concrete examples. For this population, bullying can take unconventional forms including a less direct form than that typically established among developing adolescents (Zweers, Scholte & Didden, 2017).

However, ASD can also exert a positive role in a bullying situation. Male students with ASD are more likely than regular children to avoid bullying or interfere when witnessing such behavior towards others. This is likely due to the values instilled by special education that explicitly support prosocial behavior. However, assuming the role of defender or outsider may alternatively result from role distributions based on social difficulties. ASD students who adopt these roles may struggle with understanding how to act in bullying situations. Furthermore, ASD students requiring special education tend to be victimized more commonly than those in regular classrooms.

Emotional dysregulation and a lack of social understanding by ASD adolescents can act as a catalyst for misinterpreting the behavior cues of their normally developing counterparts (Zweers et al., 2017). This creates the paradox that ASD students are more likely to stand out and be subject to bullying if they are in special education, yet despite the heterogeneity of unique needs and difficulties that the students demonstrate, special education provides necessary vital support.

Effects of Victimisation

Bullying can have a range of consequences for both the victim and the bully. This negative interaction with peers leads to both short- and long-term effects. A large body of research has demonstrated that both the perpetrator and the victim suffer from adjustment difficulties affecting academic or professional success and the ability to form healthy social relationships as well as leading to psychological issues.

Findings showed that bullies exhibited aggressive behaviors, tendencies towards violence, hyperactivity, and externalization, many of which characteristics lead to delinquency in later years. Meanwhile, those experiencing victimization displayed instances of illness, truancy, school avoidance, fear, and anxiety as well as suicidal tendencies in the short term. In the long term, these students demonstrated low self-esteem, depression, and anxiety that affected academic performance and quality of life. Both groups showed suicidal ideation, worrisome for parents and educators (Swearer et al., 2010).

It should be noted that although evidence supports these findings, the nature of some of the connections between the act of bullying, victimization, and psychosocial consequences are unclear as to whether they are causative, correlated, or reflective aspects of bullying.

Psycho-Social Foundations of Bullying

Bullying occurs within complex frameworks of social relationships that are affected by individual, environmental, and comparative defining traits. Each can be influenced by economic, cultural, and political factors. Settings that demonstrate increased risks of school bullying often share similar characteristics. In terms of institutional parameters, findings have been inconsistent in determining how class and school size, sociodemographic distribution, and social inequality may correlate to bullying rates.

Moreover, various perspectives view these social characteristics in differing ways. For example, while income inequality was shown to result in instances of bullying in one study, poverty levels represented by average familial income was not found to be directly associated with peer victimization (Azeredo, Rinaldi, de Moraes, Levy & Menezes, 2015). Therefore, it can be argued that the socioeconomic foundations for bullying are based not on the possession of certain characteristics but rather on a significant difference between population groups present within an institutional setting.

Morality and human understanding of social relationships are based on social, cultural, and collective perceptions constructed as a result of individual interpretation and interactions with peers. Shared social expectations inherently guide behavior and actions.

Childhood sociology maintains that children construct and actively participate in unique peer cultures that appropriate information and social norms from adults and reconstruct them within the context of their own reality and interaction. The identity that each person forms are part of a social process, not a fixed aspect, which is built through interpersonal interactions. Most commonly, individuals visualize themselves from the perspective of others and evaluate potential reactions to any actions (Thornberg & Jungert, 2013).

Therefore, social constructs and categories are formed as part of a collective process, creating each person’s unique identity. Since research indicates that bullying affects victims that share a common characteristic of odd social constructs and identities – ‘not fitting in’ – how this characteristic correlates with peer victimization should be examined in terms of how socially constructed differences are used to justify bullying.

Anecdotal evidence suggests that in peer victimization situations, bullies often regard their actions as ordinary and rational, claiming that they are targeting the victim as a violator of socially acceptable norms. This sort of decision-making and peer interaction can be identified as stigma and labeling, defining an individual based on a characteristic while producing a perspective guided by social opinion. Therefore, a label that identifies someone as ‘abnormal’ essentially stigmatizes the individual as a violator of the socially accepted standards of a social or cultural group.

Stigma serves as the primary consequence of labeling, affecting the social relationships of the victim, and constructing the individual’s social identity at school (Thornberg & Jungert, 2013). This phenomenon provides power and support for the bully, allowing atrocious actions to become more socially acceptable as the initial labeling of the victim is psychologically seen as the result of a transgression. The bully dominates the social identity of the victim, and the latter’s negative reputation is spread within peer circles. Even those not actively participating in bullying will tend to avoid socializing with victims. Meanwhile, stigmatized individuals are trapped in a vicious cycle that makes it all but impossible to improve their social situation.

The conflict inherent to bullying is that victimization is both a consequence of adjustment difficulties as well as their cause. Researchers have generally accepted this fact and have traced the direction of effect through longitudinal studies.

For example, students with low self-esteem are at an increased risk for bullying, but the victimization itself impacts self-esteem levels for the remainder of the academic year and the likelihood of maladjustment in consequent semesters (Fox & Boulton, 2006). Similar trends impact ASD students who experience bullying. Their psychological and educational differences place them at risk of bullying, but they can also experience significant setbacks as a result of aggressive behaviors.

An additional psychosocial explanation for bullying behaviors may be related to familial relationships. Although no direct correlation has been identified, participants in bullying may become juvenile offenders. Steinberg, Blatt-Eisengart, and Cauffman (2006) attempted to draw a relationship between patterns of relations with parents and the consequent characterization of social competence and adjustment.

The researchers’ results proved similar in both poor, minority groups and affluent, mostly white communities. Authoritative parental styles are associated with psychological maturity, academic competence, and the ability to maintain emotional stability, common to individuals who are less prone to problematic behaviors. Meanwhile, neglectful and indulgent parental styles have been shown to lead to troublesome behavior and immaturity (Steinberg et al., 2006). Although most students fall somewhere between the two extremes, this suggests that both parental influences and institutional strategies can be used to control bullying and promote competence and maturity.

Thus, the socio-ecological framework appears the most appropriate approach in identifying psycho-social foundations of bullying. Adolescent behavior is strongly influenced by individual characteristics that are constructed within the contexts of schools, communities, and institutions. Social influences affect behavioral development over the years as a number of systems such as families, peers, schools, culture, and communities establish pre-established beliefs, perceptions, and standards in the mind of a child.

While further research is necessary, the socio-ecological framework seems to offer the most holistic perspective on the issue. Behavioral change in children is based on situational process-oriented contexts (Swearer et al., 2010). Therefore, positive peer influences or supportive institutional climates can have a significantly beneficial impact on deterring bullying as well as employing adequate school strategies.

School Strategies

Schools that implement rules and regulations against bullying, adopt anti-bullying attitudes, and actively intervene against violence demonstrate lower rates of peer victimization. Commonly, anti-bullying efforts in educational institutions include comprehensive programs administered to the general school population. The primary objective of these is to spread awareness about the negative effects of bullying, identify bullying behaviors, and offer strategies for peers and instructors to prevent negative interactions (Azeredo et al., 2015).

Although such programs demonstrate improvements in bullying rates in general, the effectiveness of prevention efforts is not always successful or consistent. The following subsections will explore various approaches and strategies that schools can implement in pursuing anti-bullying efforts.

Recognizing and Addressing Gateway Behaviours

As discussed, bullying takes varied shapes and forms, many of which may not be evident or may not directly violate school policy. This is particularly true in the early stages of child development and evolving bullying situations, wherein these can be termed as ‘gateway behaviors’. In such cases, although school rules that prevent bullying are being obeyed, actions demonstrate tendencies of social maladjustment and repeated negativity or hostility. Often these behaviors, consisting of mean comments or teasing, are performed without fear of punishment. Formal discipline cannot be applied in such cases, nor would it be appropriate or realistic (Englander, 2017).

However, on a consistent basis, gateway behaviors can easily transition to violent bullying. It is the goal of educators and schools to respond to such behaviors in a manner that ensures civilized and socially acceptable interaction amongst peers.

It is important to offer guidance to students who are demonstrating gateway behaviors. This can be done both collectively through class discussions and individually in the form of a personalized approach. However, it is vital to avoid drawing attention to the target or the target’s feelings in the discussion as well as to prevent the bully from shifting any responsibility to the victim. Instead, the approach should focus on emphasizing how such actions are toxic to the school and the community environment.

The primary lesson should highlight the impacts of socially cruel behaviors on the climate and relationships within the school, thus negatively affecting bullies themselves. It is critical that a bully should gain an understanding of the reasons why society and schools prohibit peer victimization as the outcome for both individuals and the broader community can be consequential (Englander, 2017). Although the gateway behavior approach does not rule out formal discipline, it offers a chance for early recognition and rehabilitation, particularly in younger students that may not benefit from strict punishment at first offense.

Fostering Positive Social Relationships and Peer Support

Interactionism implies that people behave in terms of collective action, fitting personal behaviors to match those of others. Bullying is a phenomenon based largely on fitting in; victimized children will desperately attempt to become accepted members of society to avoid the general situation in which misfits (those who express or communicate sentiments different from the societal status quo) are faced with exclusion or violence (Thornberg & Jungert, 2013).

Based on the socio-ecological model for bullying, research suggests that positive social relationships can offer significant benefits in terms of preventing bullying. For example, families can play a role in providing emotional support and helping individuals develop coping skills. With adequate training, parents can address concerns about bullying with children, communicating the consequences of this behavior, and becoming actively involved in a child’s life (Bradshaw, 2015).

Meanwhile, schools can emphasize traditional methods of bullying prevention by introducing aspects such as Social and Emotional Aspects of Learning (SEAL), which promote teaching emotional and social skills to students. Behaviors such as respect for others (particularly marginalized groups), empathy, cooperation, and coping are some of the many positive attitudes that can be taught to improve collective cohesiveness and harmony (Rigby, 2017).

The primary factors that put children at risk for bullying are maladjustment and poor social skills. Lack of social competency results in traits such as submissiveness and non-assertiveness. In combination, social risk factors such as lack of friendship or acceptance by peers act as potential catalysts for bullying. While research has not established a direct correlation between the number of friends and rates of bullying, the quality of friendships and social identity of peers have been identified as factors. Friends are able to provide an extensive range of social support behaviors that prevent bullying or provide comfort for the victim after it occurs. In bullying scenarios, friends have been observed to assume a defender’s role, using verbal and physical actions in an attempt to repel attack (Fox & Boulton, 2006).

Educational institutions have the ability to foster social groups – and potentially friendship – as a preventive measure for bullying. Both schools and parents can foster these friendships by offering group activities, play dates, participation in sports, and social interactions that will lead to cooperation. This strategy is particularly helpful in the early developmental years as primary school children are more open to social participation in activities necessary for forming close relationships (Bayer et al., 2018).

As a result, friendships formed in the early years are more likely to lead to healthy social relationships in the adolescent years when bullying becomes prevalent. Even when students are unable to maintain a friendship for an extended time, the experience of forming social relationships and cooperation will contribute to social adjustment and potentially lessen the risk of bullying.

Comprehensive Programs

School-wide anti-bullying programs have undergone a significant evolution as more information has become available regarding the psychology of bullying and decades of observation and experience have been systematically and competently integrated into school programs. The essential goals of an anti-bullying campaign are to increase awareness and prevent such behaviors through a combination of measures. These goals are best achieved by actively changing the school social environment, reducing opportunities for bullying, limiting the potential benefits of such behavior, and creating the sense of a tight-knit community for students and teachers.

One of the best-known approaches to school-wide bullying prevention is the Olweus Bullying Prevention Program (OBPP), based on four essential principles that adults in schools and homes should demonstrate. These include showing warmth and interest, establishing strict limits to negative behaviors, using consistent and non-hostile methods of punishment, and maintaining the role of authority and positive role models (Olweus & Limber, 2010). These principles are effectively implemented within specific interventions targeted at all levels ranging from the community and the school to individuals.

At the school level, the OBPP establishes a Bullying Prevention Coordinating Committee (BPCC) that implements staff training, evaluates levels of bullying in the institution, and develops tools to measure bullying rates and the effectiveness of interventions. The committee holds extensive authority, allowing the introduction of school policies, initiating staff meetings, and reforming the school’s supervisory and disciplinary systems.

They can also modify the curriculum and implement student-based programs that introduce anti-bullying initiatives. Furthermore, the committee can establish partnerships at the community level to ensure similar values are emphasized at after-school events as well as address individual student concerns and bullying situations (Olweus & Limber, 2010). As a program, the OBPP has been developed on the principle that bullying should not be a common experience for youth.

Research indicates that bullying decreases exponentially with comprehensive, school-wide efforts that target every aspect of the institution’s function while implementing anti-bullying measures. In order to reduce opportunities for bullying and increase rewards for building a strong community, significant effort is required on the part of staff and administrators. However, the cultural shift that emerges, as a result, provides long-term benefits for everyone (Olweus & Limber, 2010).

As discussed, bullying exerts prolonged social consequences for both bully and victim, impacting their well-being, health, and level of success. Therefore, favorable outcomes for school-wide programs can have a significant positive impact on society in terms of economic savings, public health, citizen satisfaction, and the general community consensus.

However, some comprehensive school-wide programs may suffer significant setbacks, failing to produce the desired effect. One limitation may be found in evidence-based support. Many interventions heavily rely on student questionnaires and self-reported measures that are potentially invalid and may represent unreliable indicators of bullying. The stigma surrounding bullying often leads to underreporting.

In addition, programs may not be developed properly under a focused and evidence-based theoretical framework to guide development, implementation, and evaluation. Another cause of failure is a lack of intervention aimed at the sociological and psychological causes of bullying, instead of introducing preventive or punitive measures. Finally, some programs are unable to reach students effectively, which can result from poor consideration of demographics, failing to incorporate radical factors such as race, disability, and sexual orientation into marginalized groups affected by bullying.

Also, programs aimed at the general population may fail to focus on the small group of students responsible for initiating bullying behaviors and who require prosocial behavior lessons (Swearer et al., 2010). These issues in school-wide programs should be considered and eliminated through a competent approach to program development. Comprehensive preparation and research can create a precedent to avoid such errors in the future.

School-wide programs should focus on influencing the school environment through a supportive response to victims. These children should be protected from harm at the same time the attempt is made to reduce the incidence of bullying. It is warranted to introduce secondary preventive efforts to increase competence and support from teachers and peers. As a result, victims will experience a favorable environment and be subject to less emotional distress (Juvonen, Schacter, Sainio & Salmivalli, 2016).

A primary objective of comprehensive programs, school administration, and government ministries should be to establish a safer learning environment for students, a vital characteristic for parents and students who see schooling as a necessary aspect of daily life and future development. Bullying poses a significant challenge to safety due to distorted social power dynamics. As a result, comprehensive school programs can address the issue through a multifaceted approach and reduce the occurrence of adverse incidents.

Public Health Approach

Research supports adopting the public health model as a recommended method to address bullying and behavioral issues amongst students. This three-tiered model is increasing in popularity in education, correctional facilities, and public health. In special education, the model is also known as the ‘response-to-intervention framework’. Following this approach, an intervention is introduced to the general population of a particular group or class.

If students do not respond to the tier 1 intervention, they progress to the next tier interventions, which are more intensive and targeted. While offering an entire range of psychological support, the process continues until symptoms or behavior patterns are resolved (Bradshaw, 2015). As mentioned, anti-bullying programs in schools that influence the educational environment, shift social norms, and introduce bystander pressure are universal in nature, aimed at the majority of students. Although potentially appropriate, this approach fails to target the participants in bullying, the perpetrator and the victim, individuals who may often be socially maladjusted or do not respond well to universal systems of support and intervention.

In a public health approach, next-tier intervention may introduce targeted means that focus on comprehensive social skills training, emotional regulation, and conflict resolution techniques. This is particularly beneficial for students at risk who may be involved in bullying. The final tier of intervention focuses on strong support programs and oversight for both bullies and victims who may demonstrate at-risk behavior for juvenile delinquency.

Such targeted interventions attempt to pinpoint mental and social health issues as part of preventive measures. If possible, the families of the children are involved, and a support system is created and tailored to the individual needs of students who exemplify negative bullying actions (Bradshaw, 2015). The three-tiered system should be developed into a coherent and intermittent framework that can be applied to various bullying situations and used to meet the correctional needs of youth that are not adequately responding to universal interventions.

School bullying is a systemic and relevant issue in modern-day education. This negative social phenomenon is growing and extending into new areas, such as cyberspace, and taking on new forms. Bullying can affect anyone, but certain groups, such as students with ASD, are marginalized and targeted due to their lack of social adaptivity. Psycho-social theories state that bullying is a complex issue, based on maladjustment and socio-ecological influences, and can be driven by a wide variety of factors.

Taking the available comprehensive research into account, schools should develop effective and multicomponent strategies to address bullying. Fostering positive social relationships and peer support through friendship can prevent incidents of bullying. Meanwhile, comprehensive programs and a public health approach are vital to introducing both institutional and individual-level interventions to deter peer victimization. In conclusion, the field requires extensive research on the long-term impacts of such strategies as well as their effectiveness on a large scale.

Azeredo, C. M., Rinaldi, A. E. M., de Moraes, C. L., Levy, R. B., & Menezes, P. R. (2015). School bullying: A systematic review of contextual-level risk factors in observational studies. Aggression and Violent Behavior, 22 , 65–76. Web.

Bayer, J. K., Mundy, L., Stokes, I., Hearps, S., Allen, N., & Patton, G. (2018). Bullying, mental health and friendship in Australian primary school children. Child and Adolescent Mental Health, 23 (4), 334-340. Web.

Bradshaw, C. P. (2015). Translating research to practice in bullying prevention. American Psychologist, 70 (4), 322–332. Web.

Englander, E. K. (2017). Understanding bullying behavior: What educators should know and can do . American Educator, 40 (4), 24-29. Web.

Espelage, D. L., & Swearer, S. M. (2008). Current perspectives on linking school bullying research to effective prevention strategies. School Violence and Primary Prevention, 11 , 335-353.

Fox, C. L., & Boulton, M. J. (2006). Friendship as a moderator of the relationship between social skills problems and peer victimisation. Aggressive Behavior, 32 (2), 110–121. Web.

Juvonen, J., Schacter, H. L., Sainio, M., & Salmivalli, C. (2016). Can a school-wide bullying prevention program improve the plight of victims? Evidence for risk × intervention effects. Journal of Consulting and Clinical Psychology, 84 (4), 334–344. Web.

Olweus, D., & Limber, S. P. (2010). Bullying in school: Evaluation and dissemination of the Olweus Bullying Prevention Program. American Journal of Orthopsychiatry, 80 (1), 124–134. Web.

Rigby, K. (2017). School perspectives on bullying and preventative strategies: An exploratory study. Australian Journal of Education, 61 (1), 24–39. Web.

Steinberg, L., Blatt-Eisengart, I., & Cauffman, E. (2006). Patterns of competence and adjustment among adolescents from authoritative, authoritarian, indulgent, and neglectful homes: A replication in a sample of serious juvenile offenders. Journal of Research on Adolescence, 16 (1), 47–58. Web.

Swearer, S. M., Espelage, D. L., Vaillancourt, T., & Hymel, S. (2010). What can be done about school bullying? Educational Researcher, 39 (1), 38–47. Web.

Thornberg, R., & Jungert, T. (2013). School bullying and the mechanisms of moral disengagement. Aggressive Behavior, 40 (2), 99–108. Web.

Tokunaga, R. S. (2010). Following you home from school: A critical review and synthesis of research on cyberbullying victimisation. Computers in Human Behavior, 26 (3), 277–287. Web.

Zweers I., Scholte R., & Didden R. (2017). Bullying among youth with autism spectrum disorders. In J. Leaf (ed.) Handbook of social skills and autism spectrum disorder. Autism and child psychopathology series (pp. 45-61). Cham, Switzerland: Springer.

Cite this paper

  • Chicago (N-B)
  • Chicago (A-D)

StudyCorgi. (2020, December 15). Prevention of Bullying in Schools. https://studycorgi.com/prevention-of-bullying-in-schools/

"Prevention of Bullying in Schools." StudyCorgi , 15 Dec. 2020, studycorgi.com/prevention-of-bullying-in-schools/.

StudyCorgi . (2020) 'Prevention of Bullying in Schools'. 15 December.

1. StudyCorgi . "Prevention of Bullying in Schools." December 15, 2020. https://studycorgi.com/prevention-of-bullying-in-schools/.

Bibliography

StudyCorgi . "Prevention of Bullying in Schools." December 15, 2020. https://studycorgi.com/prevention-of-bullying-in-schools/.

StudyCorgi . 2020. "Prevention of Bullying in Schools." December 15, 2020. https://studycorgi.com/prevention-of-bullying-in-schools/.

This paper, “Prevention of Bullying in Schools”, was written and voluntary submitted to our free essay database by a straight-A student. Please ensure you properly reference the paper if you're using it to write your assignment.

Before publication, the StudyCorgi editorial team proofread and checked the paper to make sure it meets the highest standards in terms of grammar, punctuation, style, fact accuracy, copyright issues, and inclusive language. Last updated: December 15, 2020 .

If you are the author of this paper and no longer wish to have it published on StudyCorgi, request the removal . Please use the “ Donate your paper ” form to submit an essay.

essay on prevention of bullying

  • High contrast
  • Press Centre

Search UNICEF

Cyberbullying: what is it and how to stop it, what teens want to know about cyberbullying..

Cyberbullying: What is it and how to stop it

  • Available in:

We brought together UNICEF specialists, international cyberbullying and child protection experts, and teamed up with Facebook, Instagram, Snapchat, TikTok and X to answer some of the most common questions about online bullying and give advice on ways to deal with it. 

What is cyberbullying?

Cyberbullying is bullying with the use of digital technologies. It can take place on social media, messaging platforms, gaming platforms and mobile phones. It is repeated behaviour, aimed at scaring, angering or shaming those who are targeted. Examples include:

  • spreading lies about or posting embarrassing photos or videos of someone on social media
  • sending hurtful, abusive or threatening messages, images or videos via messaging platforms
  • impersonating someone and sending mean messages to others on their behalf or through fake accounts.

Face-to-face bullying and cyberbullying can often happen alongside each other. But cyberbullying leaves a digital footprint – a record that can prove useful and provide evidence to help stop the abuse.

If you are worried about your safety or something that has happened to you online, you can seek help by calling your national helpline . If your country does not have a helpline, please urgently speak to an adult you trust or seek professional support from trained and experienced carers.

The top questions on cyberbullying

  • Am I being bullied online? How do you tell the difference between a joke and bullying?
  • What are the effects of cyberbullying?
  • How can cyberbullying affect my mental health?
  • Who should I talk to if someone is bullying me online? Why is reporting important?
  • I’m experiencing cyberbullying, but I’m afraid to talk to my parents about it. How can I approach them?
  • How can I help my friends report a case of cyberbullying especially if they don’t want to do it?
  • How do we stop cyberbullying without giving up access to the internet?
  • How do I prevent my personal information from being used to manipulate or humiliate me on social media?
  • Is there a punishment for cyberbullying?
  • Technology companies don’t seem to care about online bullying and harassment. Are they being held responsible?
  • Are there any online anti-bullying tools for children or young people?

Am I being bullied online? How do you tell the difference between a joke and bullying?

1. Am I being bullied online? How do you tell the difference between a joke and bullying?

All friends joke around with each other, but sometimes it’s hard to tell if someone is just having fun or trying to hurt you, especially online. Sometimes they’ll laugh it off with a “just kidding,” or “don’t take it so seriously.” 

But if you feel hurt or think others are laughing at you instead of with you, then the joke has gone too far. If it continues even after you’ve asked the person to stop and you are still feeling upset about it, then this could be bullying.

And when the bullying takes place online, it can result in unwanted attention from a wide range of people including strangers. Wherever it may happen, if you are not happy about it, you should not have to stand for it.

Call it what you will – if you feel bad and it doesn’t stop, then it’s worth getting help. Stopping cyberbullying is not just about calling out bullies, it’s also about recognizing that everyone deserves respect – online and in real life.

> Back to top

What are the effects of cyberbullying?

2. What are the effects of cyberbullying?

When bullying happens online it can feel as if you’re being attacked everywhere, even inside your own home. It can seem like there’s no escape. The effects can last a long time and affect a person in many ways:

  • Mentally – feeling upset, embarrassed, stupid, even afraid or angry 
  • Emotionally – feeling ashamed or losing interest in the things you love
  • Physically – tired (loss of sleep), or experiencing symptoms like stomach aches and headaches 

The feeling of being laughed at or harassed by others, can prevent people from speaking up or trying to deal with the problem. In extreme cases, cyberbullying can even lead to people taking their own lives. 

Cyberbullying can affect us in many ways. But these can be overcome and people can regain their confidence and health.

Illustration - boy with face buried in hands

3. How can cyberbullying affect my mental health?

When you experience cyberbullying you might start to feel ashamed, nervous, anxious and insecure about what people say or think about you. This can lead to withdrawing from friends and family, negative thoughts and self-talk, feeling guilty about things you did or did not do, or feeling that you are being judged negatively. Feeling lonely, overwhelmed, frequent headaches, nausea or stomachaches are also common.

You can lose your motivation to do the things that you usually enjoy doing and feel isolated from the people you love and trust. This can perpetuate negative feelings and thoughts which can adversely affect your mental health and well-being.

Skipping school is another common effect of cyberbullying and can affect the mental health of young people who turn to substances like alcohol and drugs or violent behaviour to deal with their psychological and physical pain. Talking to a friend, family member or school counsellor you trust can be a first step to getting help.

The effects of cyberbullying on mental health can vary depending on the medium through which it happens. For example, bullying via text messaging or through pictures or videos on social media platforms has proven to be very harmful for adolescents.   

Cyberbullying opens the door to 24-hour harassment and can be very damaging. That’s why we offer in-app mental health and well-being support through our feature “ Here For You .” This Snapchat portal provides resources on mental health, grief, bullying, harassment, anxiety, eating disorders, depression, stress, and suicidal thoughts. It was developed in partnership with leading international advocacy and mental health organizations to help Snapchatters contend with some very real issues. Still, our foundational piece of guidance for any well-being issue is to talk to someone: a friend, parent, caregiver, trusted adult – anyone whom you trust to listen.

At Snap, nothing is more important than the safety and well-being of our community.  Reach out and tell us how we might be able to help.    

Cyberbullying has the potential of having a negative impact on people's mental health. It's why it's so important that you reach out to someone you trust – whether it's a parent, teacher, friend or caregiver – and let them know what you're going through so that they can help you.

The well-being of our community matters hugely to us, and we recognise that cyberbullying can have an adverse impact on people's mental health. As well as taking strong action against content or behaviour that seeks to shame, bully or harass members of our community, we have partnered with experts to develop our well-being guide to help people learn more about improving their well-being, and keep TikTok a safe and inclusive home for our community.

Who should I talk to if someone is bullying me online? Why is reporting important?

4. Who should I talk to if someone is bullying me online? Why is reporting important?

If you think you’re being bullied, the first step is to seek help from someone you trust such as your parents, a close family member or another trusted adult.

In your school you can reach out to a counsellor, the sports coach or your favourite teacher – either online or in person.

And if you are not comfortable talking to someone you know, search for a helpline in your country to talk to a professional counsellor.

If the bullying is happening on a social platform, consider blocking the bully and formally reporting their behaviour on the platform itself. Social media companies are obligated to keep their users safe.

For bullying to stop, it needs to be identified and reporting it is key.

It can be helpful to collect evidence – text messages and screen shots of social media posts – to show what’s been going on.

For bullying to stop, it needs to be identified and reporting it is key. It can also help to show the bully that their behaviour is unacceptable.

If you are in immediate danger, then you should contact the police or emergency services in your country.

Facebook/Instagram

At Meta, we take bullying and harassment situations seriously. Bullying and harassment is a unique challenge and one of the most complex issues to address because context is critical. We work hard to enforce against this content while also equipping our community with tools to protect themselves in ways that work best for them.

If you're experiencing bullying online, we encourage you to talk to a parent, teacher or someone else you can trust – you have a right to be safe and supported.

We also make it easy to report bullying directly within Facebook or Instagram. You can send our team a report from a post, comment, story or direct message (DM). Your report is anonymous; the account you reported won’t see who reported them. We have a team who reviews these reports 24/7 around the world in 70+ languages and we will remove anything that violates our policies.

Meta’s Family Center offers resources, insights and expert guidance to help parents, guardians and trusted adults support their teen’s online experiences across our technologies. Additionally, the Meta Safety Center provides bullying prevention resources that can help teens seeking support for issues related to bullying like what to do if you or a friend is being bullied or if you've been called a bully. For educators , we have expert-backed tips on how to proactively handle and work to implement bullying prevention strategies

Bullying is something no one should have to experience, either in person or online. 

Snapchat’s Community Guidelines clearly and explicitly prohibit bullying, intimidation, and harassment of any kind. We don’t want it on the platform; it’s not in keeping with why Snapchat was created and designed. Learn more here .

Letting us know when you experience or witness someone breaking our rules allows us to take action, which helps to protect you and other members of our community. In addition to reporting violating content or behaviour to Snapchat, speak with a friend, parent, caregiver, or other trusted adult. Our goal is for everyone to stay safe and have fun!

Everyone has the right to feel safe and to be treated with respect and dignity. Bullying and harassment are incompatible with the inclusive environment we aim to foster on TikTok. 

If you ever feel someone is bullying you or otherwise being inappropriate, reach out to someone you trust - for example, a parent, a teacher or a caregiver – who can provide support.

We deploy both technology and thousands of safety professionals to help keep bullying off TikTok. We also encourage our community members to make use of the easy in-app reporting tools to alert us if they or someone they know has experienced bullying. You can report videos, comments, accounts and direct messages so that we can take appropriate action and help keep you safe. Reports are always confidential. 

You can find out more in our Bullying Prevention guide for teens, caregivers, and educators on how to identify and prevent bullying, and provide support.

Being the target of bullying online is not easy to deal with. If you are being cyberbullied, the most important thing to do is to ensure you are safe. It’s essential to have someone to talk to about what you are going through. This may be a teacher, another trusted adult, or a parent. Talk to your parents and friends about what to do if you or a friend are being cyberbullied.

We encourage people to report accounts to us that may break our  rules . You can do this on our  Help Center  or through the in-Tweet reporting mechanism by clicking on the “Report a Tweet” option.

Last updated: January 2022.

I’m experiencing cyberbullying, but I’m afraid to talk to my parents about it. How can I approach them?

5. I’m experiencing cyberbullying, but I’m afraid to talk to my parents about it. How can I approach them?

If you are experiencing cyberbullying, speaking to a trusted adult – someone you feel safe talking to – is one of the most important first steps you can take.

Talking to parents isn’t easy for everyone. But there are things you can do to help the conversation. Choose a time to talk when you know you have their full attention. Explain how serious the problem is for you. Remember, they might not be as familiar with technology as you are, so you might need to help them to understand what’s happening.

They might not have instant answers for you, but they are likely to want to help and together you can find a solution. Two heads are always better than one! If you are still unsure about what to do, consider reaching out to other trusted people . There are often more people who care about you and are willing to help than you might think!

How can I help my friends report a case of cyberbullying especially if they don’t want to do it?

6. How can I help my friends report a case of cyberbullying especially if they don’t want to do it?

Anyone can become a victim of cyberbullying. If you see this happening to someone you know, try to offer support.

It is important to listen to your friend. Why don’t they want to report being cyberbullied? How are they feeling? Let them know that they don’t have to formally report anything, but it’s crucial to talk to someone who might be able to help.

Anyone can become a victim of cyberbullying.

Remember, your friend may be feeling fragile. Be kind to them. Help them think through what they might say and to whom. Offer to go with them if they decide to report. Most importantly, remind them that you’re there for them and you want to help.

If your friend still does not want to report the incident, then support them in finding a trusted adult who can help them deal with the situation. Remember that in certain situations the consequences of cyberbullying can be life threatening.

Doing nothing can leave the person feeling that everyone is against them or that nobody cares. Your words can make a difference.

We know that it can be hard to report bullying, but everyone deserves to feel safe online. If your friend is experiencing cyberbullying, encourage them to talk to a parent, a teacher or an adult they trust.

Reporting content or accounts to Facebook or Instagram is anonymous and can help us better keep our platforms safe. Bullying and harassment are highly personal by nature, so in many instances, we need a person to report this behaviour to us before we can identify or remove it. You can report something you experience yourself, but it’s also just as easy to submit a report for one of your friends. You can find more information on how to report something on our How to Report Bullying section  at the Meta Safety Center.

You and your friends may be reluctant to report to a technology platform for any number of reasons, but it’s important to know that reporting on Snapchat is confidential and easy. And remember: You can report Snaps (photos and videos), Chats (messages) and accounts – about your own experiences or on behalf of someone else. 

In the more public places of Snapchat, like Stories and Spotlight, simply press and hold on the piece of content and a card with “Report Tile” (as one option) will appear in red. Click that link and our reporting menu will appear. Bullying and harassment are among the first categories in the reporting list. Just follow the prompts and provide as much information as you can about the incident. We appreciate you doing your part to help us protect the Snapchat community!  

If you believe another member of the TikTok community is being bullied or harassed, there are ways you can provide support. For example, you can make a confidential report on TikTok so that we take appropriate action and help keep your friend safe. 

If you know the person, consider checking in with them and encourage them to read our Bullying Prevention guide so they can find out more information about how to identify bullying behaviour and take action.

If your friends are experiencing cyberbullying, encourage them to talk to a parent, a teacher or an adult they trust.

If a friend of yours does not want to report their experience, you can submit a bystander report  on their behalf. This can include reports of private information , non -consensual nudity  or impersonation.

Being online gives me access to lots of information, but it also means I am open to abuse. How do we stop cyberbullying without giving up access to the Internet?

7. How do we stop cyberbullying without giving up access to the Internet?

Being online has so many benefits. However, like many things in life, it comes with risks that you need to protect against.

If you experience cyberbullying, you may want to delete certain apps or stay offline for a while to give yourself time to recover. But getting off the Internet is not a long-term solution. You did nothing wrong, so why should you be disadvantaged? It may even send the bullies the wrong signal — encouraging their unacceptable behaviour. 

We need to be thoughtful about what we share or say that may hurt others.

We all want cyberbullying to stop, which is one of the reasons reporting cyberbullying is so important. But creating the Internet we want goes beyond calling out bullying. We need to be thoughtful about what we share or say that may hurt others. We need to be kind to one another online and in real life. It's up to all of us!

We’re continuously developing new technologies  to encourage positive interactions and take action on harmful content, and launching new tools to help people have more control over their experience. Here are some tools you can use:

  • Comment warnings: When someone writes a caption or a comment that our AI detects as potentially offensive or intended to harass, we will show them an alert that asks them to pause and reflect on whether they would like to edit their language before it’s posted.
  • Comment and message controls: Comments with common offensive words, phrases or emojis, and abusive messages or messages from strangers can be automatically hidden or filtered out with the ‘ Hidden words ’ setting, which is defaulted on for all people. If you want an even more personalized experience, you can create a custom list of emojis, words or phrases you don’t want to see, and comments containing these terms won’t appear under your posts and messages will be sent to a filtered inbox. All Instagram accounts have the option to switch off DMs from people they don’t follow. Messenger also gives you the option to ignore a conversation and automatically move it out of your inbox, without having to block the sender.
  • Block and Mute: You can always  block  or  mute  an account that is bullying you, and that account will not be notified. When you block someone on Instagram, you’ll also have the option to block other accounts they may have or create, making it more difficult for them to interact with you.
  • Restrict: With ‘Restrict,’ you can protect your account from unwanted interactions in a quieter, or more subtle way. Once Restrict is enabled, comments on your posts from a person you have restricted will only be visible to that person. You can choose to view the comment by tapping “See Comment”; approve the comment so everyone can see it; delete it; or ignore it. You won’t receive any notifications for comments from a restricted account.
  • Limits:  You can automatically hide comments and DM requests from people who don’t follow you, or who only recently followed you. If you’re going through an influx of unwanted comments or messages — or think you may be about to — you can turn on Limits and avoid it.

Our priority is to foster a welcoming and safe environment where people feel free to express themselves authentically. Our Community Guidelines make clear that we do not tolerate members of our community being shamed, bullied or harassed. 

We use a combination of technology and moderation teams to help us identify and remove abusive content or behaviour from our platform. 

We also provide our community with an extensive range of tools to help them better control their experience – whether it's control over exactly who can view and interact with your content or filtering tools to help you stay in control of comments. You can find out about them on our Safety Centre . 

Since hundreds of millions of people share ideas on X every day, it’s no surprise that we don’t all agree with each other all the time. That’s one of the benefits of a public conversation in that we can all learn from respectful disagreements and discussions.

But sometimes, after you’ve listened to someone for a while, you may not want to hear them anymore. Their right to express themselves doesn’t mean you’re required to listen. If you see or receive a reply you don’t like, unfollow  and end any communication with that account. If the behaviour continues, it is recommended that you block the account . If you continue receiving unwanted, targeted and continuous replies on X, consider reporting the behaviour to X here .

We are also working proactively to protect people using our service through a combination of human review and technology. Learn more about how to feel safer on X here .

How do I prevent my personal information from being used to manipulate or humiliate me on social media?

8. How do I prevent my personal information from being used to manipulate or humiliate me on social media?

Think twice before posting or sharing anything on digital platforms – it may be online forever and could be used to harm you later. Don’t give out personal details such as your address, telephone number or the name of your school.

Learn about the privacy settings of your favourite social media apps. Here are some actions you can take on many of them: 

  • You can decide who can see your profile, send you direct messages or comment on your posts by adjusting your account privacy settings. 
  • You can report hurtful comments, messages, photos and videos and request they be removed.
  • Besides ‘unfriending’, you can completely block people to stop them from seeing your profile or contacting you.
  • You can also choose to have comments by certain people to appear only to them without completely blocking them.
  • You can delete posts on your profile or hide them from specific people. 

On most of your favourite social media, people aren't notified when you block, restrict or report them.

Is there a punishment for cyberbullying?

9. Is there a punishment for cyberbullying?

Most schools take bullying seriously and will take action against it. If you are being cyberbullied by other students, report it to your school.

People who are victims of any form of violence, including bullying and cyberbullying, have a right to justice and to have the offender held accountable.

Laws against bullying, particularly on cyberbullying, are relatively new and still do not exist everywhere. This is why many countries rely on other relevant laws, such as ones against harassment, to punish cyberbullies.

In countries that have specific laws on cyberbullying, online behaviour that deliberately causes serious emotional distress is seen as criminal activity. In some of these countries, victims of cyberbullying can seek protection, prohibit communication from a specified person and restrict the use of electronic devices used by that person for cyberbullying, temporarily or permanently.

However, it is important to remember that punishment is not always the most effective way to change the behaviour of bullies. Sometimes, focusing on repairing the harm and mending the relationship can be better.

On Facebook, we have a set of  Community Standards , and on Instagram, we have  Community Guidelines . We take action when we are aware of content that violates these policies, like in the case of bullying or harassment, and we are constantly improving our detection tools so we can find this content faster.

Bullying and harassment can happen in many places and come in many different forms from making threats and releasing personally identifiable information to sending threatening messages and making unwanted malicious contact. We do not tolerate this kind of behavior because it prevents people from feeling safe and respected on our apps.

Making sure people don’t see hateful or harassing content in direct messages can be challenging, given they’re private conversations, but we are taking steps to take tougher action when we become aware of people breaking our rules. If someone continues to send violating messages, we will disable their account. We’ll also disable new accounts created to get around our messaging restrictions and will continue to disable accounts we find that are created purely to send harmful messages.

On Snapchat, reports of cyberbullying are reviewed by Snap’s dedicated Trust & Safety teams, which operate around the clock and around the globe. Individuals found to be involved in cyberbullying may be given a warning, their accounts might be suspended or their accounts could be shut down completely. 

We recommend leaving any group chat where bullying or any unwelcome behaviour is taking place and please report the behaviour and/or the account to us.  

Our Community Guidelines define a set of norms and common code of conduct for TikTok and they provide guidance on what is and is not allowed to make a welcoming space for everyone. We make it clear that we do not tolerate members of our community being shamed, bullied or harassed. We take action against any such content and accounts, including removal.

We strongly enforce our rules to ensure all people can participate in the public conversation freely and safely. These rules specifically cover a number of areas including topics such as:

  • Child sexual exploitation
  • Abuse/harassment
  • Hateful conduct
  • Suicide or self-harm
  • Sharing of sensitive media, including graphic violence and adult content

As part of these rules, we take a number of different enforcement actions when content is in violation. When we take enforcement actions, we may do so either on a specific piece of content (e.g., an individual Tweet or Direct Message) or on an account.

You can find more on our enforcement actions here .

Internet companies don’t seem to care about online bullying and harassment. Are they being held responsible?

10. Technology companies don’t seem to care about online bullying and harassment. Are they being held responsible?

Technology companies are increasingly paying attention to the issue of online bullying.

Many of them are introducing ways to address it and better protect their users with new tools, guidance and ways to report online abuse.

But it is true that more is needed. Many young people experience cyberbullying every day. Some face extreme forms of online abuse. Some have taken their own lives as a result.

Technology companies have a responsibility to protect their users especially children and young people.

It is up to all of us to hold them accountable when they’re not living up to these responsibilities.

Are there any online anti-bullying tools for children or young people?

11. Are there any online anti-bullying tools for children or young people?

Each social platform offers different tools (see available ones below) that allow you to restrict who can comment on or view your posts or who can connect automatically as a friend, and to report cases of bullying. Many of them involve simple steps to block, mute or report cyberbullying. We encourage you to explore them.

Social media companies also provide educational tools and guidance for children, parents and teachers to learn about risks and ways to stay safe online.

Also, the first line of defense against cyberbullying could be you. Think about where cyberbullying happens in your community and ways you can help – by raising your voice, calling out bullies, reaching out to trusted adults or by creating awareness of the issue. Even a simple act of kindness can go a long way.

The first line of defense against cyberbullying could be you.

If you are worried about your safety or something that has happened to you online, urgently speak to an adult you trust. Many countries have a special helpline you can call for free and talk to someone anonymously. Visit  United for Global Mental Health to find help in your country.

We have a number of anti-bullying tools across Facebook and Instagram:

  • You can block people, including any existing and new accounts they might create.
  • You can  mute  an account and that account will not be notified.
  • You can limit unwanted interactions for a period of time by automatically hiding comments and message requests from people who don’t follow you, or who only recently followed you.
  • You can use ‘ Restrict ’ to discreetly protect your account without that person being notified.
  • You can  moderate comments  on your own posts.
  • You can  modify your settings  so that only people you follow can send you a direct message.
  • We will notify someone when they’re about to post something that might cross the line, encouraging them to reconsider.
  • We automatically filter out comments and message requests that don’t go against our Community Guidelines but may be considered inappropriate or offensive. You can also create your own custom list of emojis, words or phrases that you don’t want to see.

For more tips and ideas, visit Instagram’s Safety page and Facebook’s Bullying Prevention Hub . We also offer resources, insights and expert guidance for parents and guardians on our Family Center .

We want teens and young adults to be aware of the blocking and removal functions on Snapchat. Clicking on the person’s avatar will bring up a three-dot menu in the upper right-hand corner. Opening that menu offers the option of “Manage Friendship,” which, in turn, offers the ability to Report, Block or Remove the person as a friend. Know that if you block someone, they will be told that their Snaps and Chats to you will be delivered once the relationship is restored.  

It’s also a good idea to check privacy settings to ensure they continue to be set to the default setting of “Friends Only.” This way, only people you’ve added as Friends can send you Snaps and Chats.  

We also recommend reviewing your Friends’ list from time to time to ensure it includes those people you still want to be friends with on Snapchat.  

Alongside the work that our safety teams do to help keep bullying and harassment off our platform, we provide an extensive range of tools to help you control your TikTok experience. You can find these in full on our Safety Centre . Here are a few highlights:

  • You can restrict who comments on your videos to no one, just friends or everyone (for those aged under 16, the everyone setting is not available)
  • You can filter all comments or those with specific keywords that you choose. By default, spam and offensive comments are hidden from users when we detect them.
  • You can delete or report multiple comments at once, and you can block accounts that post bullying or other negative comments in bulk too, up to 100 at a time.
  • A comment prompt asks people to reconsider posting a comment that may be inappropriate or unkind, reminding them of our Community Guidelines and allowing them to edit their comments before sharing.

We want everybody to be safe on X. We continue to launch and improve tools for people to feel safer, be in control and manage their digital footprint. Here are some safety tools anyone on X can use: 

  • Select who can reply to your Tweets  – either everyone, only people you follow or only people you mention
  • Mute – removing an account's Tweets from your timeline without unfollowing or blocking that account
  • Block – restricting specific accounts from contacting you, seeing your Tweets, and following you
  • Report – filing a report about abusive behaviour
  • Safety mode  – a feature that temporarily blocks accounts for using potentially harmful language or sending repetitive and uninvited replies or mentions.

With special thanks to:  Meta, Snap, TikTok and X (formerly known as Twitter). Last updated: February 2024.

To anyone who has ever been bullied online: You are not alone

TikTok stars Charli and Dixie D'Amelio open up about their personal experience of being bullied and share tips on how to make the internet a better place.

Reporting abuse and safety resources

Facebook instagram kik snapchat, tiktok tumblr wechat whatsapp youtube x, take action to stop cyberbullying.

The consequences of cyberbullying can be devastating. Youth can take action to stop it

5 ways to support your mental health online

Tips on how to look after yourself and others

Contribute to Kindly - help stop cyberbullying

Kindly - A UNICEF initiative to end cyberbullying — one message at a time

Mental health and well-being

Tips and resources to help you support your child and yourself

Home / Essay Samples / Social Issues / Bullying / Bullying Prevention And Safety

Bullying Prevention And Safety

  • Category: Social Issues
  • Topic: Bullying , Cyber Bullying , Youth Violence

Pages: 1 (516 words)

Views: 2367

  • Downloads: -->

--> ⚠️ Remember: This essay was written and uploaded by an--> click here.

Found a great essay sample but want a unique one?

are ready to help you with your essay

You won’t be charged yet!

Cruelty to Animals Essays

Discrimination Essays

Animal Testing Essays

Capital Punishment Essays

Related Essays

We are glad that you like it, but you cannot copy from our website. Just insert your email and this sample will be sent to you.

By clicking “Send”, you agree to our Terms of service  and  Privacy statement . We will occasionally send you account related emails.

Your essay sample has been sent.

In fact, there is a way to get an original essay! Turn to our writers and order a plagiarism-free paper.

samplius.com uses cookies to offer you the best service possible.By continuing we’ll assume you board with our cookie policy .--> -->