NSSI Contagion in Adolescent Friendships: Explore the process of peer influence

Objective Although empirical evidence of NSSI contagion within adolescent friendships has been documented, the specific mechanisms remain poorly understood. The current study employed a longitudinal design to investigate the influence of NSSI in adolescents’ peer groups on their own NSSI behaviors. Additionally, the study examined the mediating role of self-esteem and the specific conditions under which NSSI contagion occurs. Method The study involved 326 adolescents (mean age = 13.5, 59.2% female) nested within 163 friendship dyads. NSSI behavior, self-esteem, self-compassion, alexithymia, and personal distress were assessed at baseline (T1), and NSSI behavior was assessed again after three months (T2). A cross-lagged Actor-Partner Interdependence Model (APIM) was used to estimate the NSSI contagion model. In this model, self-esteem served as a mediator in the contagion of NSSI behaviors, while alexithymia, self-compassion, and personal distress acted as moderating factors of this mediating effect. Results This study revealed that friends’ NSSI status at baseline significantly predicted adolescents’ own NSSI status after three months. Self-esteem was found to mediate the NSSI contagion effect exclusively in situations where adolescents exhibited high alexithymia, low self-compassion, and high personal distress. Conclusions This research highlights the role of adolescent friendships in NSSI contagion and elucidates the potential mediating role of self-esteem in this contagion. These findings may provide substantial implications for the prevention of the NSSI contagion among adolescents.