Bullying is one of the most common adverse experiences of childhood and adolescence, with verbal and social forms alone reported by roughly half of all students in large surveys. It is also far from limited to schoolyards: workplace bullying affects a sizable share of adults, and cyberbullying has blurred the line between school hours and private life. Research over the past two decades has reshaped how scientists understand bullying, revealing it as something more strategic and biologically consequential than the old “kids will be kids” framing ever suggested.
How Common Bullying Is and What Forms It Takes
Bullying is not a single behavior. It shows up as physical aggression, verbal attacks, social manipulation (spreading rumors, deliberate exclusion), and electronic harassment. A nationally representative U.S. study of adolescents found that over a two-month window, about 54% reported involvement in verbal bullying, 51% in social bullying, 21% in physical bullying, and about 14% in cyberbullying, whether as the person doing the bullying or the one on the receiving end.1PubMed Central. School Bullying Among US Adolescents: Physical, Verbal, Relational and Cyber An Italian study of adolescents found a broadly similar pattern, with verbal bullying at 52% and relational bullying at about 48%, though it also captured forms less commonly measured, including sexual bullying at roughly 19% and racist bullying at about 9%.2PubMed. Different forms of bullying and their association to smoking and drinking behavior in Italian adolescents
The fact that verbal and social bullying are so much more prevalent than physical bullying matters. Physical aggression is the most visible form, the kind adults are likeliest to notice and intervene against. But name-calling, gossip campaigns, and deliberate exclusion make up the bulk of what young people experience, and these forms are harder to detect, easier to deny, and at least as harmful to the target’s mental health.
Why People Bully
One persistent misconception is that bullies are socially incompetent loners lashing out because they lack better skills. Research paints a more uncomfortable picture. A study of over a thousand Dutch children aged 9 to 12 found that those who led bullying incidents were often “bistrategics,” meaning they used both coercive and prosocial strategies and tended to hold high social standing among peers. Ringleader bullies also expressed a stronger desire to be socially dominant. The researchers concluded that bullying functions as dominance-oriented strategic behavior, not a deficit in social skills.3PubMed. Bullying as strategic behavior: relations with desired and acquired dominance in the peer group
This does not mean every child who bullies is a calculating social climber. Some are genuinely struggling with impulse control or responding to chaotic home environments. But the finding that many bullies are socially skilled and strategic is important because it changes how prevention should work. Programs that only teach social skills to bullies may miss the point entirely; these kids already know how to read a room. What they lack is a reason to stop, because the behavior is working for them.
Neuroimaging research adds another layer. A small fMRI study of adolescents with aggressive conduct disorder found that when they watched scenes of someone in pain, their brains activated differently than those of matched controls. While control youth showed increased activity in prefrontal regions associated with moral reasoning and perspective-taking, the aggressive youth showed reduced coupling between the amygdala and prefrontal cortex, suggesting weaker top-down regulation of emotional responses to others’ suffering.4PubMed Central. Atypical empathic responses in adolescents with aggressive conduct disorder: a functional MRI investigation This was a small, preliminary study, and conduct disorder is not the same thing as bullying. But it hints that for some aggressive youth, the neural wiring around empathy may genuinely differ.
What Bullying Does to the Body
The effects of being bullied go beyond hurt feelings. A growing body of research shows that repeated victimization changes how the body handles stress at a hormonal level. Cortisol, the body’s main stress hormone, follows a predictable daily rhythm and spikes in response to challenging situations. In children who have been bullied, this system appears to malfunction. One study of 12-year-olds who had experienced both maltreatment and bullying found that their cortisol responses to stress were significantly blunted compared to children who had not been victimized, and lower cortisol was linked to more social and behavioral problems.5PubMed Central. Blunted Cortisol Responses to Stress Signal Social and Behavioral Problems Among Maltreated/Bullied 12-Year-Old Children
Other research has found a flattened cortisol awakening response in victims, paired with higher cortisol immediately after a stressor and lower cortisol in the recovery period, a pattern associated with more physical health problems.6PubMed. Worse than sticks and stones? Bullying is associated with altered HPA axis functioning and poorer health A study of Chinese children found that bullied children showed both higher cortisol reactivity and higher total cortisol during a stress test compared to nonbullied children, with no differences between types of victimization, whether physical, verbal, or relational.7PubMed. Bullying Victimization Heightens Cortisol Response to Psychosocial Stress in Chinese Children The direction of dysregulation varies across studies and populations, but the consistent finding is that bullying leaves a measurable fingerprint on the stress system.
How Bullying Shapes Brain Development
Perhaps the most striking recent finding is that bullying appears to alter the physical development of the brain. A longitudinal MRI study tracking young people from adolescence into early adulthood found that higher levels of bullying victimization were linked to accelerated growth in subcortical and limbic areas, including the amygdala, hippocampus, and putamen, regions associated with threat detection and emotional processing. At the same time, victimization was associated with reduced growth in areas like the insula, the cerebellum, and parts of the cortex involved in sensory integration and self-awareness.8PubMed Central. Bullying victimization and brain development: a longitudinal structural magnetic resonance imaging study from adolescence to early adulthood
In plain terms, the brains of bullied young people seem to develop faster in areas that process fear and social threat, and slower in areas involved in self-regulation and higher-order thinking. The researchers also noted sex-specific patterns in these trajectories. This does not prove that bullying alone caused the differences, since the study could not control for every possible factor, but the longitudinal design (measuring the same individuals over time) strengthens the case that these are consequences of victimization rather than pre-existing differences.
Psychological and Long-Term Outcomes
A systematic review and meta-analysis of the consequences of bullying victimization in childhood and adolescence found the strongest evidence for links between being bullied and depression, anxiety, poor general health, and suicidal thoughts and behaviors.9PubMed Central. Consequences of bullying victimization in childhood and adolescence: A systematic review and meta-analysis These are not just short-term reactions. A British birth cohort study tracking people over five decades found that participants who were frequently bullied in childhood had roughly double the odds of depression and suicidal thoughts at midlife, and about 65% higher odds of anxiety disorders, even after adjusting for family background and other childhood adversities. Being bullied in childhood was also associated with fewer social relationships, economic hardship, and poorer quality of life at age 50.10PubMed. Adult health outcomes of childhood bullying victimization: evidence from a five-decade longitudinal British birth cohort
Another long-running study found that victims of childhood bullying were at elevated risk for poor health, reduced wealth, and troubled social relationships in adulthood, even after controlling for family hardship and childhood psychiatric disorders. The researchers stated plainly that being bullied is “not a harmless rite of passage but throws a long shadow over affected people’s lives.”11PubMed Central. Impact of bullying in childhood on adult health, wealth, crime, and social outcomes Research on adult income specifically found that victimization at ages 9 to 14 was negatively associated with later earnings, with the pattern differing by sex: for girls, being socially excluded was linked to lower adult income, while for boys, having belongings taken was the form most associated with income differences.12New Directions for Child and Adolescent Development. Associations Between Childhood Bullying Victimization and Adult Income: Longitudinal Evidence From a Representative US Sample
The Bully-Victim Group
Not everyone falls neatly into the role of bully or victim. A subgroup of young people both perpetrates and receives bullying, and research consistently identifies them as the most vulnerable. A longitudinal population-based cohort study noted that these “bully-victims” appear to be at the highest risk of poor mental health outcomes.13PubMed. Bully/victims: a longitudinal, population-based cohort study of their mental health The long-term cohort study mentioned earlier also found that bully-victims, alongside pure victims, had worse adult outcomes in health, wealth, and relationships, whereas those classified as pure bullies did not show elevated risk once other childhood factors were accounted for.14PubMed Central. Impact of bullying in childhood on adult health, wealth, crime, and social outcomes This finding complicates any narrative that frames bullying as having two clear sides. The young person who is most at risk may be the one caught in both roles.
Gender Differences in Bullying
Boys and girls are both involved in bullying as victims and perpetrators, but the forms they experience tend to differ. A study analyzing gender differences in bullying involvement found that boys were victimized more across most types of bullying, though the only statistically significant gender gap was in physical aggression.15PubMed Central. The involvement of girls and boys with bullying: an analysis of gender differences Girls, meanwhile, are more likely to experience indirect forms like teasing and social exclusion. Some researchers have argued that the historical emphasis on direct, physical bullying in measurement tools has led to an undercount of girls’ experiences. When indirect bullying is measured properly, the gender gap in overall victimization narrows considerably.16Youth Violence and Juvenile Justice. Correlates and Consequences of Peer Victimization: Gender Differences in Direct and Indirect Forms of Bullying
Cyberbullying and Online Disinhibition
Cyberbullying adds a layer that older forms of bullying lack: it follows the target home. There is no refuge in leaving the school building when harassment continues via group chats, social media, and anonymous messaging apps. A systematic review of online disinhibition and cyberbullying found that the more disinhibited young people feel online, the more likely they are to engage in cyberbullying. The review also found that online disinhibition works partly through moral disengagement and poor self-control, meaning that the anonymity and distance of screens make it easier for people to act in ways they would not face to face.17Children and Youth Services Review. Online disinhibition and adolescent cyberbullying: A systematic review
This helps explain why cyberbullying sometimes involves people who would never bully someone in person. The psychological barriers that normally restrain aggressive behavior, like seeing the target’s distress, worrying about being caught, or caring what onlookers think, are weakened when you are typing into a screen. It also explains why cyberbullying can feel especially relentless to victims: the aggressor does not see the impact and therefore does not self-correct.
The Role of Bystanders
Most bullying happens in front of other people, making bystanders one of the most important variables in whether an incident escalates or stops. A qualitative study of bystander motivation identified five themes that shape whether someone intervenes: how they interpret the harm being done, their emotional reaction, their social evaluation of the situation, their moral evaluation, and their confidence that intervening will actually help.18PubMed Central. Bystander Motivation in Bullying Incidents: To Intervene or Not to Intervene? Self-efficacy, the belief that you can actually do something useful, was linked to victim-defending behavior in another study of bystander intervention.19Psychology in the Schools. Bystander intervention style and motivational factors influencing behavior in bullying situations
Whether other bystanders are present also changes the calculus. A study comparing bystander behavior when others were present versus absent found that different factors mattered in each scenario. With other bystanders around, a person’s defending behavior was influenced by their relationship to the victim, the severity of the harm, and the bystander’s own popularity. When the bystander was alone with the situation, their past experience as a victim, their empathy level, and their sense of personal control became the drivers.20School Psychology International. Investigation of the bystander effect in school bullying: Comparison of experiential, psychological and situational factors This is the classic bystander effect playing out in a school hallway: the more witnesses, the more diffused the sense of personal responsibility.
Workplace Bullying
Bullying does not end at graduation. A meta-analysis pooling data from more than 115,000 workers found clear associations between workplace bullying and symptoms of depression, anxiety, and stress-related complaints. Longitudinal data from over 54,000 workers confirmed that workplace bullying predicted mental health problems over time. The same analysis also found a reverse path: people with baseline mental health difficulties were more likely to report being bullied later, suggesting a vicious cycle in which vulnerability and victimization reinforce each other.21PLoS ONE. Workplace Bullying and Mental Health: A Meta-Analysis on Cross-Sectional and Longitudinal Data
Context shapes workplace bullying in ways that differ from schoolyard dynamics. Role conflict, the stress of receiving contradictory demands at work, has been shown to increase exposure to bullying, which in turn increases symptoms resembling post-traumatic stress. One study found that incompetent management strengthened this chain, while skilled managers weakened it.22PubMed Central. Workplace Bullying and Post-Traumatic Stress Disorder Symptomology: The Influence of Role Conflict and the Moderating Effects of Neuroticism and Managerial Competencies Several factors appear to buffer adults against the worst mental health effects: being male, being younger, having shorter tenure in the role, and lower educational level all showed up as protective in one study, while bullying by a supervisor was more damaging than peer bullying, and perceiving multiple perpetrators made things worse.23PubMed Central. Bullying at Work and Mental Health: The Moderating Role of Demographic and Occupational Variables
Socioeconomic Roots
Bullying is often treated as an individual behavior problem, but it tracks with broader social and economic conditions. A cross-national study of 35 countries found that adolescents from less affluent families reported higher rates of victimization. More striking, the overall wealth of a country did not matter much; what did predict higher bullying was large economic inequality, both within schools and at the national level.24PubMed Central. Socioeconomic Inequality in Exposure to Bullying During Adolescence: A Comparative, Cross-Sectional, Multilevel Study in 35 Countries A separate analysis of 37 countries similarly found that income inequality was correlated with bullying rates, with each increase in inequality corresponding to higher odds of bullying for both boys and girls.25Journal of Adolescent Health. Income Inequality, Trust, and Public Health in 37 Countries
At the neighborhood level, resource deprivation has been found to predict bullying perpetration more strongly than generalized aggression, even after controlling for other risk factors like parental arrest, domestic violence, and trauma. One study found that the link between racial category and bullying was fully explained by neighborhood resource deprivation, suggesting that what appears to be a racial pattern in bullying perpetration may actually be an economic one.26PubMed Central. Neighborhood Resource Deprivation as a Predictor of Bullying Perpetration and Resource-Driven Conduct Symptoms
What Actually Reduces Bullying
The evidence on anti-bullying interventions is mixed in a way that should make people cautious about any single program. KiVa, a Finnish program that focuses heavily on changing bystander behavior, has shown effectiveness in multiple settings. A large randomized trial in the Netherlands found that both self-reported victimization and bullying decreased more in KiVa schools than in control schools, with stronger effects after two years of implementation.27PubMed Central. A Large-Scale Replication of the Effectiveness of the KiVa Antibullying Program: a Randomized Controlled Trial in the Netherlands However, a trial of the same program in Wales did not find a statistically significant effect on the primary outcome of child-reported victimization.28PubMed Central. The Effectiveness of the KiVa Bullying Prevention Program in Wales, UK: Results from a Pragmatic Cluster Randomized Controlled Trial This does not mean the program is useless, but it does mean that a program proven effective in one country may not automatically transfer to another, likely because school culture, implementation quality, and local norms all affect outcomes.
Policy-level interventions also show promise. A study across 25 U.S. states found that students in states whose anti-bullying laws included specific components, like a clear statement of scope, descriptions of prohibited behaviors, and requirements for schools to develop local policies, had roughly a quarter lower odds of reporting being bullied and about a fifth lower odds of reporting cyberbullying compared to students in states without those components.29JAMA Pediatrics. Associations Between Antibullying Policies and Bullying in 25 States
At the classroom level, how teachers respond to bullying matters enormously. An experimental study found that when a hypothetical teacher actively corrected the bully, students perceived stronger anti-bullying norms, were more willing to report future incidents, and expected less bullying in the classroom going forward. Merely comforting the victim without addressing the bully was less effective. The strongest effects came from responses that made it explicitly clear that the bullying behavior itself would not be tolerated.30PubMed Central. Perceived Teacher Responses to Bullying Influence Students’ Social Cognitions
What Protects Young People Who Are Bullied
Not every young person who is bullied develops lasting psychological problems, and research has identified relationships as one of the strongest buffers. A study that separated between-person and within-person effects found that adolescents who generally received more support from friends suffered less from the emotional consequences of peer victimization, experiencing fewer symptoms of depression and anxiety.31PubMed Central. Peer Victimization, Internalizing Problems, and the Buffering Role of Friendship Quality: Disaggregating Between- and Within-Person Associations A separate study found that support from both classmates and parents protected adolescents against ongoing victimization and reduced the impact of bullying on later psychological distress.32Journal of Child and Family Studies. The Protective Role of Supportive Relationships in Mitigating Bullying Victimization and Psychological Distress in Adolescents
The practical upshot is that even when bullying itself cannot be immediately stopped, surrounding a victimized young person with supportive relationships, from parents, friends, and school staff, can meaningfully change the trajectory. Isolation amplifies the harm of bullying; connection absorbs some of it. For parents trying to figure out how to help a child who is being bullied, strengthening those relationship networks may be as important as anything happening at the institutional level.
Cultural Variation and What It Tells Us
Bullying exists everywhere researchers have looked for it, but its forms and visibility vary by culture. A cross-national study spanning 62 countries and over 428,000 students examined whether a country’s level of cultural individualism predicted student aggression and victimization. Students’ own reports of being victimized, whether physically, verbally, or relationally, showed no significant relationship to their country’s individualism score. However, school principals in more individualist countries reported observing more aggressive student behavior.33PubMed. The relationship between cultural individualism-collectivism and student aggression across 62 countries One interpretation is that the behavior itself occurs at similar rates everywhere, but adults in different cultural contexts recognize and label it differently. In more collectivist cultures, some aggressive behavior may be managed within peer groups without ever reaching adult awareness, or it may take forms (like exclusion and shaming for nonconformity) that principals are less likely to identify as “bullying.”
This matters because anti-bullying efforts that work in one cultural context may fail in another not because the underlying behavior is different, but because the social dynamics around it are. A program built for a Scandinavian school system, with its relatively flat social hierarchies and high trust in institutions, may not translate directly to a context with different norms about authority, conformity, and peer relationships. The Wales trial of KiVa hints at exactly this kind of cultural friction.