Bullying is a distinctive pattern of repeatedly and deliberately harming and humiliating others, specifically those who are smaller, weaker, younger or in any way more vulnerable than the bully. The deliberate targeting of those of lesser power is what distinguishes bullying from garden-variety aggression .
Why Does Bullying Develop?
Understanding what causes bullying is essential for prevention and treatment. Research consistently shows that bullying arises from a complex interplay of biological, psychological, and social factors — rarely from a single cause.
What Researchers Have Found
Research into bullying has identified multiple contributing pathways. Studies using neuroimaging, genetics, and longitudinal data reveal that no single factor fully explains why bullying develops.
Biological Factors
Biological contributors to bullying include:
- Genetics: Family history increases risk; certain genes influence vulnerability
- Brain chemistry: Neurotransmitter imbalances (serotonin, dopamine, norepinephrine) play key roles
- Brain structure: Differences in the prefrontal cortex, amygdala, and hippocampus are documented
- Physical health: Chronic illness, hormonal changes, and sleep disruption can trigger or worsen bullying
Psychological Factors
- Early experiences: Childhood adversity, attachment disruption, and trauma shape psychological vulnerability
- Cognitive patterns: Negative thinking styles, perfectionism, and rumination increase risk
- Coping skills: Limited emotional regulation skills make bullying more likely under stress
- Personality: Certain traits (neuroticism, harm avoidance) are associated with higher risk
Social and Environmental Factors
Environmental factors — including chronic stress, relationship problems, financial difficulty, and major life events — can trigger bullying in vulnerable individuals.
What Triggers an Episode?
Even in people with predisposing factors, bullying often requires a triggering event:
- Major life transitions (job loss, relationship breakdown, bereavement)
- Prolonged stress without adequate recovery
- Substance use or withdrawal
- Physical illness or injury
- Social isolation or conflict
Protective Factors
Not everyone with risk factors develops bullying. Protective factors include: strong social support, effective coping skills, physical health maintenance, access to care, and psychological resilience built through prior challenges.