A study of the symptom network structure of internet addiction, non-suicidal self-injury and internalization problems in adolescents and its association with physical activity.

OBJECTIVE: Internet addiction (IA), internalizing problems (IP), and non-suicidal self-injury (NSSI) are major public health concerns with far-reaching implications. However, few studies have examined their interrelationships with physical activity (PA) from a symptom-level perspective using network analysis. This study aimed to construct an IA-IP-PA symptom network and identify the symptoms most directly associated with NSSI. METHODS: A total of 898 students aged 9 to 16 were recruited from two schools. Data were collected using the Revised Chinese Internet Addiction Scale (CIAS-R), Adolescent Non-Suicidal Self-Injurious Behavior Scale, Physical Activity Rating Scale (PARS-3), and the Brief Problem Monitor. The network structure was estimated using EBICglasso, and central and bridge symptoms were identified. RESULTS: The prevalence rates of IA and NSSI were 8.4% (n = 76) and 29.6% (n = 266), respectively. The most central symptoms in the network were "interpersonal and health-related problems," "social anxiety," and "worthlessness." Key bridge symptoms included "interpersonal and health-related problems," "social anxiety," and "fear." Among all symptoms, tolerance showed the strongest direct association with NSSI. PA was negatively associated with all symptom nodes, particularly "interpersonal and health-related problems" and tolerance." CONCLUSION: Social anxiety and interpersonal/health-related problems appear to be central drivers of comorbidity across IA, IP, and NSSI. Distress tolerance is closely linked to NSSI, while regular physical activity may buffer against IA, IP, and self-injurious behaviors. Targeted interventions focusing on these key symptoms are essential for promoting adolescent mental and physical well-being.