Parental psychological control and problematic smartphone use in Chinese early adolescents: shyness as a mediator and teacher–student relationship as a moderator

Problematic smartphone use (PSU) has become an increasingly prominent concern among early adolescents. Although prior research has consistently linked parental psychological control (PPC) to adolescents’ problematic smartphone use, less is known about how family, school, and individual factors jointly relate to PSU during early adolescence. Guided by the Interactional Theory of Childhood Problematic Media Use (IT-CPU), this study examined the associations among PPC, teacher–student relationship (TSR), shyness, and PSU in a sample of 1,176 early adolescents from Shandong Province, China. Participants completed standardized questionnaires administered in classroom settings. Results indicated that PPC positively predicted PSU, and shyness partially mediated this association. In addition, TSR moderated the association between PPC and shyness. Specifically, the link between PPC and shyness was not significant under conditions of low TSR, whereas a stronger positive association emerged under high TSR, revealing an anti-buffering effect. These findings highlight the joint role of family, school, and individual factors in early adolescents’ problematic digital behavior and suggest the value of coordinated family–school support in prevention efforts within the Chinese educational context.