Trajectories of Bullying Victimization and Perpetration in Australian School Children and Their Relationship to Future Delinquency and Conduct Problems

Objective: Joint trajectories of bullying victimization and perpetration were extracted in a large representative sample of Australian schoolchildren for the purpose of gauging the prevalence of bully-only, victim-only, and bully-victim growth trajectories. Results were then correlated with delinquency and conduct disorder measures to determine whether the trajectories differed with respect to these antisocial outcomes. Method: A large sample of schoolchildren (N = 3,460, 49.4% female) was assessed at three different time points-age 12/13 (Wave 5), age 14/15 (Wave 6), and age 16/17 (Wave 7). A sequential process growth mixture modeling analysis was then performed on Wave 5 to 7 bullying victimization and perpetration data. Results: Six separate trajectories were identified, the largest of which (84.1% of the sample) was characterized by very low levels of bullying victimization and perpetration. The other five trajectories consisted of two victim-only trajectories (accelerating and decelerating) and three bully-victim trajectories (moderate stable, high accelerating, and high decelerating). No bully-only trajectories surfaced. Comparing the trajectories against Wave 7 measures of self-reported delinquency and parent-reported conduct problems revealed results consistent with predictions (bully-victim accelerating/decelerating/stable > victim-only > low stable) for the delinquency outcome only. Conclusions: These results suggest that bullying perpetration frequently accompanies bullying victimization. For this reason, assessment protocols that are expanded to cover both behaviors and treatment programs are required that provide services to both the perpetrators and victims of bullying. There is also a need for more research on the question of whether bullying-only trajectories exist.