Bullying perpetration, peer victimisation, suicidality, and their cumulative effect on preadolescents' behaviour and brain development

BackgroundAdolescents suicidality and peer bullying are rising as a serious public health concern globally. However, the neural correlates of perpetrators and the impact of different types of bullying perpetration/peer victimisation on preadolescents needs elucidation. Besides, there has been a lack of research studying the cumulative risk pattern of bullying perpetration/peer victimisation on preadolescents with suicidality. MethodsWe adopted a retrospective and longitudinal methodology by utilising the data from the Adolescent Brain Cognitive Development (ABCD) cohort. Firstly, participants were assigned into two groups (i.e., perpetrators vs non-perpetrators) based on their bullying perpetration experiences. Next, different types of bullying perpetration/peer victimisation (i.e., overt, relational, and reputational) were extracted to evaluate their associations with suicidal ideation (SI), non-suicidal self-injury (NSSI), and suicide attempt (SA) separately. Then, participants were further assigned into four groups (i.e., bully-uninvolved preadolescents without suicidality/NSSI history (HC group), bully-uninvolved preadolescents with SA (SA group), preadolescents with both SA and bullying perpetration (SA+P group), and preadolescents with both SA and peer victimisation (SA+V group)). We used multinomial logistic regression models, analysis of variance (ANOVA), and brain network analysis for assessing potential associations in studys objectives. FindingsIn total, 9992 individuals aged 11-12 years were included in our analysis. Of these individuals, 1111 (11.1%) were classified as perpetrators, and had significantly lower bilateral cortical volume in the superior frontal sulcus (SFS), lower functional connectivity within default mode network (DMN), and lower anti-correlation between DMN and dorsal attention network (DAN) than non-perpetrators. Additionally, preadolescents overt, relational, and reputational perpetration/ victimisation experiences were all shown to be associated with suicidality/NSSI, despite varying strengths, while overt perpetration showed the strongest association with SA (OR 3.6 [95%CI 2.4-5.4]), followed by overt victimisation (2.4 [1.6-3.5]). Besides, the SA+V group was characterised by the highest psychopathology among four groups, while the SA+P group was characterised by the highest aggression among four groups. Lastly, lower bilateral cortical volume in the precentral gyrus (PCG) while higher cortical volume in both the lateral occipitotemporal cortex (LOTC) and posterior cingulate cortex (PCC) were found in the SA+P group when compared to SA and HC group. InterpretationFindings from the present study offered empirical evidence on the impact of bullying experience, suicidality and their cumulative risk on preadolescents behavior and brain development, contributing to the growing literature on discerning the impact of different types of bullying perpetration/peer victimisation on preadolescents.