Co-occurrence Patterns and Transitions in Adolescents' Depressive Symptoms and Problematic Smartphone Use: The Roles of Social Support and Self-control.

Although many studies have indicated that problematic smartphone use and depressive symptoms are closely associated and frequently co-occur in adolescence, little is known about their heterogeneous co-occurrence profiles and how these profiles evolve over time. Using person-centered approaches (LPA and RT-LTA), this study identified the co-occurrence patterns of problematic smartphone use and depressive symptoms, examined their transitions, and investigated the roles of social support and self-control on transitions. A total of 8969 Chinese adolescents (49.3% girls; T1: Mage = 12.86, SD = 0.31) participated in the study over a one-year period with three follow-up assessments. Five co-occurrence profiles consistently emerged: low symptoms, moderate co-occurrence, PSU-dominant, depression-dominant, and high co-occurrence. The low symptoms group showed the highest stability, whereas the PSU-dominant group showed the most transitions. Boys, as well as adolescents with higher levels of social support and self-control, showed a greater likelihood of symptom improvement and a reduced risk of symptom worsening over time, with the protective roles of self-control and social support being stronger among adolescents with less severe symptoms. These findings reveal the heterogeneous manifestations in the co-occurrence of problematic smartphone use and depressive symptoms, their longitudinal transitions and the conditional effects of protective factors among adolescents.