Psychobiological Correlates of Bullying in Juvenile Offenders: Personality Traits, Psychopathic Features, and Platelet MAO-B Activity

Bullying behavior among youth is linked to long-term psychosocial and criminological consequences and is particularly prevalent yet understudied in juvenile justice settings. Stable individual differences, including personality traits, early psychopathic traits, and biological markers, may provide a framework for understanding bullying among young offenders. The present study examined whether these factors, both individually and cumulatively, were associated with bullying behavior among 370 male adolescents aged 14 to 19 years detained in a juvenile detention center in Northern Russia. Bullying behavior was evaluated using the Kiddie Schedule for Affective Disorders and Schizophrenia – Present and Lifetime Version. Data were available for subsets on personality traits measured with the Temperament and Character Inventory ( n = 320), early psychopathic traits assessed with Lynam’s Childhood Psychopathy Scale (self-report n = 136; teacher report n = 154), and platelet Monoamine Oxidase B (MAO-B) activity ( n = 178). Associations between bullying, personality traits, psychopathic traits, and MAO-B activity were examined using independent-samples t -tests, linear and logistic regression models. All analyses were conducted using available cases and adjusted for smoking. A cumulative risk index was created to examine the combined contribution of multiple risk factors, based on the top 20% in novelty seeking, psychopathic traits, and low MAO-B activity. Bullies differed from non-bullies on nearly all personality traits, showing higher novelty seeking and lower self-directedness and cooperativeness. Bullies also exhibited higher psychopathic traits (self- and teacher-rated) and lower MAO-B activity, although the MAO-B association weakened to a trend when adjusting for smoking. The likelihood of belonging to the bullying group increased with the accumulation of risk factors across personality, psychopathic traits, and MAO-B activity. We conclude that, within an already high-risk offender population, bullying is associated with the cumulative presence of personality characteristics, psychopathic traits, and biological markers, supporting a multidimensional framework of risk.