Emotion Dysregulation as a Longitudinal Mediator between Depressive Symptoms and Non-Suicidal Self-Injury in Adolescents: Insights from a Random Intercept Cross-Lagged Panel Model.

Résumé

Non-suicidal self-injury (NSSI) is a significant public health concern among adolescents. Yet, the longitudinal mechanisms linking depressive symptoms to NSSI—particularly the role of emotion dysregulation and potential sex differences—remain insufficiently understood. This study examined whether difficulties in emotion regulation (DER) serve as a within-person mediator in the longitudinal association between depressive symptoms and NSSI, and whether this indirect pathway differs between male and female adolescents. We analyzed three-wave longitudinal data collected from 1,555 Chinese adolescents (Mage = 13.97 ± 1.53; 47.85% girls) at six-month intervals. A Random Intercept Cross-Lagged Panel Model (RI-CLPM) was employed to disentangle within-person fluctuations from stable between-person differences, thereby providing a rigorous test of temporal dynamics. The results revealed a significant temporally ordered mediation pathway at the within-person level: increases in depressive symptoms predicted subsequent elevations in emotion dysregulation, which in turn predicted an increased risk of NSSI. Notably, multi-group analyses indicated that this indirect effect was significant only among female adolescents; for males, no significant mediation was observed. These findings identify emotion dysregulation as a key, sex-specific mechanism through which depressive symptoms translate into NSSI behavior over time, with a small but meaningful indirect effect (β = 0.03) at the within-person level. The results underscore the importance of targeting emotion regulation skills in interventions for adolescents with depressive symptoms, and suggest that sex-informed approaches may enhance the efficacy of prevention and early intervention efforts for NSSI.