Background: Prior literature suggests there is an association between bullying involvement in childhood and later suicidality in adolescents. However, findings are inconsistent, and few studies consider whether sex may moderate the association between bullying involvement and suicidality. We aimed to investigate the longitudinal association between bullying involvement and suicidality and consider the different roles of bullying involvement as well as the potential role sex may play in the association’s causal pathway.
Methods: A study population consisting of individuals enrolled in the Danish National Birth Cohorts (DNBC) 11 and 18 year follow ups. The 11-year follow up for both child and parent included information on bullying involvement and the 18-year follow up included self-reported information on suicidal ideation (SI) and -attempt (SA). Data from the cohort was coupled with Danish register data via a unique personal identification number. The association was estimated with multinomial logistic regressions and inverse probability weighting was applied to account for selection bias.
Results: A total of 28,997 (11,705 males and 17,292 females) individuals were included in the study sample. There was an associated increased risk for SI and SA respectively among female victims aRRR: 1.60 [95% CI 1.47-1.74] , aRRR: 2.94 [95% CI 2.48-3.49] , and for SA among bullies aRRR: 2.34 [95% CI 1.51-3.62]. There was an associated increased risk among male victims for SI aRRR: 1.62 [95% CI 1.45-1.80] and SA aRRR: 2.80 [95% CI 2.05-3.82], but male bullies had no higher risk of SI and SA. Furthermore, a modification analyses suggested that sex modifies the risk between bullying involvement in preadolescence and suicidality in late adolescence.
Conclusion: Findings support that bullying involvement in pre-adolescence was associated with increased risk for suicidality in late adolescence as compared to non-exposed peers. Further, evidence of sex-related modification implies that future interventions should consider specific elements to address sex differences.