Bullying can cause depression, anxiety, physical health problems, falling grades, and lasting changes to brain development. About one in four children and adolescents worldwide are bullying victims, based on a meta-analysis of 116 studies covering more than 600,000 young people. The effects reach far beyond hurt feelings, touching nearly every aspect of a young person’s health and future.
Depression and Anxiety
The strongest and most consistent consequence of bullying is a sharply increased risk of depression. A large meta-analysis published in BMC Psychiatry found that children and adolescents who were bullied had 2.77 times the risk of developing depression compared to those who were not. For those who both bullied others and were bullied themselves, the risk climbed even higher, to 3.19 times that of uninvolved peers. Even the perpetrators weren’t protected: children who bullied others had 1.73 times the depression risk of those with no involvement in bullying at all.
Anxiety disorders follow a similar pattern. Bullied children report higher levels of generalized anxiety, social anxiety, and lower life satisfaction. The combination of constant social threat and unpredictability trains the brain to stay on high alert, which can persist long after the bullying stops.
Suicidal Thoughts and Self-Harm
Bullying involvement is linked to a meaningful increase in suicidal thinking and behavior. A meta-analysis on bullying and suicidality found that victims of bullying had 2.23 times the odds of experiencing suicidal ideation and 2.55 times the odds of attempting suicide compared to peers who weren’t bullied. Children who were both bullies and victims carried the greatest risk. Self-destructive behaviors, including running away from home and self-harm, are recognized warning signs that a child may be experiencing bullying.
How the Body Responds to Chronic Bullying
Bullying doesn’t just affect mood. It gets under the skin in measurable, biological ways. The body’s stress response system, which controls the hormone cortisol, becomes dysregulated in bullied children. Research consistently shows that victims of bullying develop a blunted cortisol response, meaning their bodies stop reacting to stress the way they should. Bullied children tend to have lower cortisol levels in the morning and before bed, along with a flattened daily cortisol curve. This pattern mirrors what researchers see in people exposed to chronic, uncontrollable stress, and it’s associated with higher levels of inflammation.
The everyday physical symptoms are just as real. Frequent headaches, stomachaches, difficulty sleeping, and nightmares are common in bullied children. Some develop changes in eating habits, skipping meals or binge eating. These aren’t imaginary complaints. They’re the body’s response to sustained psychological threat, and they often lead to increased school absences, which compounds the academic damage.
Changes in Brain Development
Longitudinal brain imaging research has found that bullying victimization is associated with structural changes in the developing brain from adolescence into early adulthood. Specifically, bullied young people showed accelerated growth in brain regions involved in processing fear and emotion, including the amygdala and hippocampus. At the same time, they showed reduced growth in areas responsible for processing bodily sensations and memory, including the insula and entorhinal cortex.
In practical terms, this means the brain’s threat-detection system grows more reactive while regions involved in emotional regulation and complex thinking may lag behind. These aren’t small, ambiguous findings. The changes were widespread and showed different patterns in boys and girls, suggesting that bullying reshapes the brain in sex-specific ways during a critical period of development.
Falling Grades and School Avoidance
Academic performance takes a direct hit. In one longitudinal study, for each 1-point increase in self-reported victimization on a 4-point scale, students’ GPA dropped by 0.3 points. Another found a 0.44 GPA decrease for each 1-point increase on a 5-point victimization scale. When researchers looked at standardized test scores, a 1 standard deviation increase in school bullying incidents produced a 0.55 standard deviation drop in scores in the short term, with a 0.4 standard deviation decrease still present two years later.
The mechanism isn’t hard to understand. Bullied children become isolated, lose confidence in their abilities, and start viewing school as an unsafe place. This leads to avoidance, truancy, and in some cases dropping out entirely. A meta-analysis of 14 studies confirmed that children involved in bullying were significantly more likely to have low academic achievement, with victims showing roughly 38% lower odds of strong academic performance compared to uninvolved peers. The physical symptoms of bullying, like headaches and sleep problems, also contribute to absenteeism that compounds the academic slide.
What Cyberbullying Adds
Cyberbullying carries all the risks of traditional bullying with several features that can intensify the damage. Unlike face-to-face bullying, it follows the victim home. There is no safe space, no end-of-school-day relief. Perpetrators can hide behind anonymity, target large numbers of victims simultaneously, and do so at any hour. Perhaps most damaging is the digital footprint: humiliating content can be screenshotted, shared, and resurfaced indefinitely, creating a form of ongoing trauma that traditional bullying rarely produces.
Research on cybervictims shows they exhibit higher cortisol secretion compared to bystanders, suggesting their stress response is particularly activated. When coping strategies like blocking or deleting messages fail, victims report feeling completely defenseless, a sense of helplessness that is strongly linked to depression.
Long-Term Consequences for Bullies
The damage isn’t limited to victims. Longitudinal research tracking children who bully into adulthood has found they are roughly two-thirds more likely to engage in violence later in life, even after accounting for other childhood risk factors like general aggression and conduct problems. Childhood bullying behavior also predicts drug use, criminal convictions, and low-status employment in adulthood. By age 18, young people who had bullied others showed elevated rates of antisocial behavior, academic difficulties, depression, and social isolation. Bullying harms the person doing it, too, just on a different timeline.
Warning Signs to Watch For
Children who are being bullied rarely announce it directly. Instead, the signs tend to show up as changes in behavior and routine. According to StopBullying.gov, key warning signs include:
- Unexplainable injuries or lost and destroyed belongings like clothing, electronics, or books
- Physical complaints such as frequent headaches, stomachaches, or faking illness to avoid school
- Changes in eating or sleeping, including skipping meals, binge eating, nightmares, or insomnia
- Academic decline or sudden reluctance to go to school
- Social withdrawal, including sudden loss of friends or avoidance of group situations
- Emotional shifts like feelings of helplessness, decreased self-esteem, or talk of self-harm
A child coming home from school hungry because they didn’t eat lunch, or a teenager who once had a close friend group and now spends every evening alone, may be signaling something they can’t put into words. These changes, especially when several appear together, warrant a closer look.