Abstract
PURPOSE: Previous research has documented that problematic smartphone use (PSU) is associated with various psychological symptoms among adolescents, but temporal ordering and underlying mechanisms remain unclear. PATIENTS AND METHODS: This three-wave longitudinal study examined bidirectional relationships among depressive and anxious symptoms, fear of missing out (FOMO), and PSU in a sample of 402 Chinese adolescents (49.6% girls; M (age) = 12.33, SD = 0.52) assessed at six-month intervals (ie, T1, T2, and T3). RESULTS: The random-intercept cross-lagged panel modelling (RI-CLPM) results indicated a bidirectional relationship between FOMO and PSU, with each predicting subsequent increases in the other. PSU predicted increases in depressive symptoms over time (βs =0.19 -0.21, ps <0.001), but not vice versa (βs =0.05 -0.06, ps >0.05). Anxious symptoms predicted increased FOMO over time (βs =0.12 -0.13, ps <0.01), while FOMO did not predict anxious symptoms (βs =0.05 and.05, ps >0.05). FOMO at T2 mediated the linkage between depressive/anxious symptoms at T1 and PSU at T3. CONCLUSION: These findings identify FOMO as a critical mediating mechanism linking psychological symptoms to problematic digital behaviors. Interventions targeting FOMO may help disrupt these maladaptive patterns and prevent escalation of both PSU and psychological symptoms among adolescents.