Multifactorial associations of non-suicidal self-injury among adolescents with depression: a network analytic perspective

BACKGROUND: In clinical samples of adolescents with depression, the underlying causes of non-suicidal self-injury (NSSI) across different developmental stages of adolescence are not well understood. This study explored stage-specific differences by comparing psychosocial factors and investigating possible causal links between NSSI and depressive symptoms in middle adolescence (13–15 years) versus late adolescence (16–18 years). METHODS: A total of 1,530 Chinese adolescents with a diagnosis of depression were enrolled in the study. The presence of non-suicidal self-injury (NSSI) in the past year was assessed using the Functional Assessment of Self-Mutilation (FASM). Psychosocial factors were measured with the Patient Health Questionnaire (PHQ-9), Toronto Alexithymia Scale (TAS), Childhood Trauma Questionnaire (CTQ), Multidimensional Peer Victimization Scale (MPVS), and Multidimensional Scale of Perceived Social Support (MSPSS). To examine stage-specific differences in network centrality and causal pathways, partial correlation networks and Bayesian network analysis were applied. RESULTS: Depressive symptoms demonstrated a probabilistic directional association with NSSI during middle adolescence, whereas peer victimization emerged as a primary probabilistic link to NSSI in late adolescence. Gender demonstrated a stable direct edge to NSSI, with no consistent indirect paths through other measured variables. Within the directed acyclic graph, childhood trauma emerged as a putative upstream factor, exhibiting strong connections to peer victimization and social support. CONCLUSIONS: These findings indicate that factors including depressive symptoms, gender, and peer victimization exerted distinct effects on NSSI across developmental stages. Future research should prioritize the specific influence of adolescence as a dynamic developmental period on the etiology and maintenance of NSSI.