Neurodevelopmental traits as mechanisms linking genetic predispositions to bullying involvement

Developmental studies have highlighted the heritability of both bullying perpetration and victimization. However, the specific mechanisms through which genetic predispositions influence bullying dynamics remain largely unexplored. In this study, we examined how a higher-order polygenic score for neurodevelopmental problems (PGS-NDP)-including loadings for attention-deficit/hyperactivity symptoms, autism spectrum traits, and aggression-relates to bullying perpetration and victimization from end of childhood to adolescence, and whether this association is mediated by specific neurodevelopmental traits. Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC; N = 5,733 with genetic data and at least one bullying assessment), we tested four mediators measured between ages 7 and 9: inattention, hyperactivity-impulsivity, social communication difficulties, and pragmatic speech difficulties. Mediation models were adjusted for child sex, prenatal adversity, and five genetic principal components. For continuous measures of bullying involvement, we identified a similar mediated pathways linking higher PGS-NDP to greater perpetration and victimization via hyperactivity-impulsivity. Additionally, pragmatic speech difficulties mediated the associations between PGS-NDP and bullying victimization. When investigating mediational pathways between PGS-NDP and categorical bullying status (uninvolved, bully-only, victim-only and bully-victim), all four neurodevelopmental traits played mediating roles for the victim-only and bully-victim statuses, while no mediator emerged for the bully-only status. Effect sizes were small, but the mediating roles of hyperactivity-impulsivity and pragmatic speech difficulties in bullying victimization warrant further attention, particularly to clarify their potential additive and interactive contributions. Clarifying these pathways can inform the design of universal and targeted interventions aimed at reducing bullying involvement and interrupting cycles of victimization.