ABSTRACT
Depression is frequently associated with problematic social media use (PSMU), yet evidence integrating day-to-day dynamics with longer-term temporal ordering remains limited. We conducted two studies to examine these associations. In Study 1, 169 college students completed a 2-week daily diary assessing depressive symptoms adapted from the Kutcher Adolescent Depression Scale and PSMU derived from the PSMU Scale. Dynamic structural equation modelling indicated reciprocal within-person lagged effects: higher daily depression predicted higher PSMU on the next day, and higher daily PSMU also predicted higher depression on the next day. In Study 2, 473 adolescents were assessed over a 9-month period using the PSMU Scale and the Kutcher Adolescent Depression Scale at each wave. Longitudinal analyses showed that depression at T1 predicted PSMU at T2, whereas PSMU at T1 did not predict depression at T2. Together, these findings suggest that depression and PSMU may reinforce each other in daily life, but over longer periods, depression appears to be a more robust antecedent of problematic social media engagement. Implications for prevention and intervention targeting depressive symptoms and maladaptive social media use are discussed.