How negative life events and emotion regulation difficulties are associated with non-suicidal self-injury in adolescents: A dimension-level network analysis and the role of physical activity.

BACKGROUND AND OBJECTIVE: Non-suicidal self-injury (NSSI) is prevalent during adolescence and is associated with an elevated risk of subsequent suicide. Guided by the integrated theoretical model of NSSI and the cross-stressor adaptation hypothesis, this study constructed a unified dimensional network incorporating negative life events (NLEs), emotion regulation difficulties (ERD), physical activity (PA), and NSSI. The study aimed to identify nodes with high overall and cross-community connectivity, dimensions exhibiting the strongest direct conditional associations with NSSI, and the connectivity patterns of PA. Additionally, network structures were compared across sex and age-defined adolescent groups. METHODS: A total of 4427 students aged 10-19 years were recruited. Data were collected using the Deliberate Self-Harm Inventory (DSHI), Adolescent Self-Rating Life Events Checklist (ASLEC), Difficulties in Emotion Regulation Scale-16 Item Version (DERS-16), and Physical Activity Rating Scale-3 (PARS-3). Gaussian graphical models were employed to estimate the network structure and evaluate network stability. Network comparison tests were conducted to examine differences in network structure and global strength across sex groups and age-defined adolescent groups, including early adolescence (10-12 years), middle adolescence (13-15 years), and late adolescence (16-19 years). RESULTS: The mean age of participants was 14.31 years (SD = 2.85). Overall, 28.87% of participants reported NSSI, with proportions of 28.17%, 30.09%, and 28.38% in early, middle, and late adolescence, respectively. Punishment-related stress, academic stress, and limited access to effective emotion regulation strategies exhibited the highest expected influence. Lack of emotional clarity, interpersonal stress, and academic stress demonstrated the highest bridge expected influence. NSSI showed the strongest direct conditional associations with punishment-related stress and limited access to effective emotion regulation strategies. Network structure and global strength did not differ significantly by sex or developmental stage. CONCLUSION: These findings suggest that early identification and prevention of NSSI among adolescents should consider both external stressors, such as punishment-related stress, and internal regulatory vulnerabilities, particularly limited access to effective emotion regulation strategies. Physical activity, as a potentially modifiable health behavior resource, warrants further investigation through longitudinal and intervention studies.