From defeat to non-suicidal self-injury: the roles of entrapment and interpersonal relationship patterns in adolescence.

Introduction: Based on the integrated motivational-volitional model and the functional theory of self-injury, this study examined the association between defeat and adolescent non-suicidal self-injury (NSSI), with entrapment as a mediator and interpersonal relationship patterns as moderators. Methods: Participants were 4,515 secondary school students (Mage = 15.24 years, SD = 1.66). Latent profile analysis was used to identify interpersonal relationship patterns across father-child, mother-child, peer, and teacher-student relationships. A moderated mediation model was then tested to examine the direct and indirect associations between defeat and NSSI across the identified profiles. Results: Overall, 33.9% of adolescents reported engaging in NSSI at least once. Defeat, entrapment, interpersonal relationships, and NSSI were significantly correlated, and entrapment partially mediated the association between defeat and NSSI. Four interpersonal relationship profiles were identified: low, moderate, and high interpersonal relationship groups and a father-child and teacher-student relationship deficit group. Interpersonal relationship profiles moderated both the direct association between defeat and NSSI and the association between defeat and entrapment. The defeat-NSSI association was strongest in the low interpersonal relationship group, whereas the defeat-entrapment association was strongest in the high interpersonal relationship group. Discussion: The findings indicate that entrapment is an important psychological mechanism linking defeat to adolescent NSSI and that the strength of these pathways varies across adolescents' interpersonal relationship configurations. Prevention efforts may benefit from addressing both defeat-related psychological processes and adolescents' broader relational contexts.