From loneliness to internet addiction in adolescents: disentangling the within-person mediating role of rumination via RI-CLPM.

BACKGROUND: Internet addiction symptoms have received increasing research attention as a public health concern among adolescents, with well-documented negative impacts on psychological wellbeing and social functioning. Although loneliness has been identified as an important correlate and prospective risk factor for Internet addiction symptoms, the longitudinal mechanisms underlying this relationship remain underexplored. This three-wave longitudinal study examines the mediating role of rumination in the link between loneliness and internet addiction among Chinese adolescents. METHODS: A total of 743 Chinese junior high school students (Mage = 13.34, SD = 0.847; 51.7% female) completed measures of loneliness, rumination, and internet addiction at three time points spaced 6 months apart. A random intercept cross-lagged panel model (RI-CLPM) was employed to separate between-person trait variance from within-person temporal dynamics, allowing a more precise examination of reciprocal and mediational processes. RESULTS: At the between-person level, the random intercepts of loneliness, rumination, and internet addiction were not significantly correlated. At the within-personmental health crisislevel, significant bidirectional and unidirectional cross-lagged effects emerged. Specifically, higher-than-usual loneliness predicted subsequent increases in rumination and internet addiction. Elevated rumination, in turn, predicted greater subsequent internet addiction. Internet addiction was also prospectively associated with subsequent increases in both loneliness and rumination, suggesting a reciprocal within-person cycle. Longitudinal mediation analyses revealed that rumination significantly mediated the within-person pathway from loneliness to self-reported Internet addiction. However, the standardized indirect effect was modest, suggesting limited practical magnitude. The reverse indirect effect was not significant. CONCLUSIONS: By employing RI-CLPM, this study delineates the dynamic within-person processes associated with adolescent internet addiction at the individual level. These findings identify rumination as a cognitive mechanism linking the emotional experience of loneliness to the development of Internet addiction symptoms. The results suggest the potential value of targeting both loneliness and maladaptive ruminative thinking in prevention and intervention efforts aimed at reducing internet addiction among adolescents.