Internet addiction has been associated with decreased prosocial behavior in adolescents, and minority studies have investigated the underlying mechanisms involved. This study aimed to examine the mediating effects of self-control and the moderating effects of peer rejection. A longitudinal study with two waves (6 months apart) was used to measure internet addiction (T1), peer rejection (T1), self-control (T1/T2), and prosocial behavior (T1/T2) among 1048 secondary school students (M_age = 14.80 years old, SD = 1.61) in a southern Chinese metropolitan area. A longitudinal path analysis model was applied to analyze the data and derive insights about the relationships between these variables. The findings indicated that T1 internet addiction negatively influenced later prosocial behavior through reduced self-control, particularly among adolescents with lower levels of peer rejection. These findings clarify how internet addiction impairs prosocial development, and we propose a framework for intervention: mitigating peer rejection and harnessing self-control as a mediator to counteract the adverse effects of internet addiction.

Background and aims: Problematic social media use (PSMU) is a concerning public health issue among adolescents. Existing literature has paid attention to the role of singular family risk on PSMU, but how cumulative family risks affect the trajectory of PSMU needs to be further explored. Methods: The current study employed a five-wave longitudinal design that lasted for three years (each time interval: 6, 6, 12, and 12 months) to reveal the longitudinal mechanism between cumulative family risks and the trajectory of PSMU, examining the mediating roles of escape and relationship motivations. This study investigated 1,973 adolescents ( M _age = 14.51, SD _age = 1.49; age range: 11.95–17.45 years old; 47.4% females; 40% middle school) from southern China at wave 1, and the final sample size was 882 at wave 5. Results: PSMU among Chinese adolescents presented with a stable tendency. In addition, cumulative family risks positively predicted the initial level ( B = 0.21, SE = 0.02, p < 0.001) but not the slopes of PSMU. Moreover, escape motivation mediated the association between cumulative family risks and the trajectory of PSMU ( B _intercept = 0.10, SE = 0.01, 95%CI = [0.076, 0.118]; B _{linear slope} = −0.03, SE = 0.01, 95%CI = [–0.040, −0.019]; B _{quadratic slope} = 0.004, SE = 0.001, 95%CI = [0.002, 0.006]). Conclusions: Findings suggest that adolescents who experience cumulative family risks may be more likely to develop PSMU, potentially via the drive to escape from real life. A favorable family environment may be conducive to mitigating adolescent escape motivation and PSMU.