Abstract
OBJECTIVE: Adolescence is a critical period for personality development and a high-risk phase for psychological conflicts. With the increasing severity of mental health issues among adolescents, this study investigates the mechanisms underlying the relationship between internet addiction (IA) and non-suicidal self-injury (NSSI) in adolescents, focusing on the mediating roles of social anxiety and depression and the moderating effect of trait meta-mood. The aim of this study is to uncover the psychological motivations behind NSSI and provide a theoretical basis for identifying potential risks to adolescent mental health, ultimately contributing to the prevention of psychological crises. METHODS: A total of 692 high school students from Heilongjiang Province, China, completed the Internet Addiction Test (IAT), the Deliberate Self-Harm Inventory (DSHI), the Liebowitz Social Anxiety Scale (LSAS), the Beck Depression Inventory-II (BDI-II), and the Trait Meta-Mood Scale (TMMS). Structural equation modeling was used to examine the mediating and moderating effects among the variables. RESULTS: (1) A significant positive correlation was found between internet addiction and NSSI (r = 0.278, p < 0.01). (2) Social anxiety (indirect effect = 0.042) and depression (indirect effect = 0.019) formed a chain mediation pathway, explaining 26% of the total effect. (3) Trait meta-mood moderated the first half of the mediation pathway (R (2) = 0.161, p < 0.001), with the mediating effect of internet addiction being stronger at high levels of trait meta-mood (0.08) than at low levels (0.036). CONCLUSION: Internet addiction exacerbates the risk of NSSI in adolescents through a progressive pathway of "social anxiety → depression." trait meta-mood plays a crucial role in moderating this process, highlighting the importance of emotional regulation in mitigating the adverse effects of internet addiction on adolescent mental health.