Growing up with screens: Investigating gender and socioeconomic differences and social relationships in the development of problematic smartphone use

The present study investigated the longitudinal trajectory of adolescents' problematic smartphone use (PSU) from Grade 4 to Grade 8. We also examined whether the trajectory differs depending on student gender, parent educational attainment, and family income, and whether prior and concurrent social relationships predict adolescents' PSU at each time point. We employed longitudinal panel data and analyzed survey responses from Korean adolescents (N = 2399). Results of latent growth modeling revealed that the quadratic growth model best represented the trajectory of PSU from Grade 4 to Grade 8, indicating an overall increasing trend in adolescents' PSU, with the rate of this increasing trend declining over time. Additionally, student gender, parent educational attainment, and family income significantly predicted the intercept and linear slope of PSU. The contemporaneous effects of perceived social relationships with peers and teachers on PSU were significant at all time points, suggesting that current difficulties in peer and teacher relationships are consistently linked to elevated PSU. The lagged effects of student-teacher relationships on PSU were significant, whereas those of peer relationships were not, highlighting the enduring importance of teacher relationships. Additionally, the predictive power of social relationships changed over time, indicating the developmental dynamics of social relationships and their importance.