Peer victimization and family dynamics in the association between childhood abuse and adolescent non-suicidal self-injury: a cross-sectional moderated mediation study

Abstract

Childhood abuse is associated with adolescent non-suicidal self-injury (NSSI), but the roles of proximal peer experiences and family context remain unclear. A cross-sectional survey was conducted among 10,179 Chinese students (47.9% female; Mage = 14.16 years, SD = 1.86). A theoretically motivated model re-specified during peer review examined peer victimization as a statistical mediator and family dynamics (SSFD) as a moderator of the a, b, and direct paths. Analyses controlled for gender, age, and parental education and used 5,000 bootstrap resamples. Childhood abuse was positively associated with NSSI (total association: β = 0.476, p < .001). The statistical indirect association through peer victimization was 0.150 (95% CI [0.133, 0.167]). Small positive interactions were observed for CA × SSFD predicting peer victimization (β = 0.033, p < .001), PV × SSFD predicting NSSI (β = 0.031, p = .001), and CA × SSFD predicting NSSI (β = 0.046, p < .001). The interactions explained little additional variance (ΔR² = 0.001 for peer victimization and 0.005 jointly for NSSI). Conditional indirect associations were 0.109 at low SSFD and 0.157 at high SSFD; their bootstrap contrast was 0.048 (95% CI [0.011, 0.083]). The findings are compatible with an associational indirect pattern involving peer victimization and small conditional differences by family dynamics. Because all variables were self-reported at one time point, and the model was re-specified during review, the results should not be interpreted as evidence of causal or developmental mechanisms. 1. The study integrated distal, peer, and family correlates of adolescent NSSI. 2. Childhood maltreatment retained a substantial adjusted association with NSSI. 3. Peer victimization emerged as a proximal statistical indirect correlate. 4. Conditional differences by family dynamics were small and model-sensitive.