The effect of municipality-level social media use on youth mental health

Background Rising internalizing problems among youth, particularly among females, have raised concerns about potential societal causes. Social media use (SMU) has emerged as a key focus, given its widespread adoption since the early 2010s. While individual-level cross-sectional studies suggest small to moderate correlations between SMU and internalizing problems, a complementary community-based perspective allows for assessing the effects of living in environments with high or low social media use on youth mental health. Methods This study investigates the effect of SMU on internalizing symptoms among Norwegian youth in a longitudinal study at the municipality level. The study uses data from the nationwide Ungdata surveys (2014–2024), covering 528 cohorts across 181 municipalities. Anxiety and depressive symptoms were assessed using items adapted from the Hopkins Symptom Checklist and the Depressive Mood Inventory, respectively. We applied a Bayesian multilevel model using the R package brms , accounting for time-varying and time-constant confounders. Results An additional hour of average SMU corresponded to a 0.70 [0.26, 1.14] SD increase in anxiety scores for boys but showed no clear association for girls (-0.03 [-0.31, 0.24]). For depressive symptoms, a one-hour increase in average SMU corresponded to an increase of 0.25 [0.03, 0.46] for boys, with no clear effect for girls (0.02 [-0.15, 0.19]). The models accounted for a substantial proportion of variance in T2 outcomes (r² = .6 - .8). Conclusion Assuming that all relevant factors influencing both social media use and youth mental health were accounted for, the findings suggest that living in communities with high social media use may have a small effect on youth mental health symptoms. However, these effects are inconsistent and primarily observed among boys.