Abstract
BACKGROUND: Internet addiction is a growing concern among adolescents, with childhood maltreatment recognized as a significant risk factor. According to the Interaction of Person-Affect-Cognition-Execution model, childhood maltreatment can lead to affective responses, such as depression, which in turn heighten vulnerability to internet addiction. However, the potential protective role of external factors, such as physical activity, in this pathway remains underexplored. This study investigates the mediating role of depression and the moderating role of physical activity in the relationship between childhood maltreatment and adolescent internet addiction. METHODS: Data from 1610 Chinese middle school students were analyzed using statistical software: Mplus 8.3 was used for SEM, while SPSS 26.0 and Hayes' PROCESS Macro were used for correlation analyses, hierarchical regression, and moderated mediation model. RESULTS: Results showed that emotional abuse was significantly positively associated with internet addiction and the association was mediated by depression. In addition, physical activity moderates the first stage of mediating the effect of depression between emotional abuse and internet addiction. Furthermore, adolescents with lower levels of physical activity exhibited a stronger indirect effect of emotional abuse on internet addiction compared to those in the higher physical activity group. SEM also demonstrated that the model exhibited good fit, reliability, and discriminant validity. CONCLUSION: The results show that depression mediated the relationship between emotional abuse and adolescent internet addiction. In addition, the association of emotional abuse and depression is weaker for adolescents who participate more in physical activity. This study emphasizes the necessity of addressing physical activity and provides theoretical guidance for prevention of internet addiction.