Association Between Smartphone Screen Time and Mental Health Among Korean Adolescents: A National Representative Study

OBJECTIVE: Evidence linking smartphone use to adverse mental health outcomes is increasing, but the association between screen time and adolescent mental health remains unclear. Thus, this study aimed to examine these associations among adolescents in South Korea. METHODS: We analyzed data from students aged 12-18 years who participated in the Korean Youth Risk Behavior Web-based Survey from 2020 to 2024. Smartphone screen time was grouped as 4 hours per day, and mental health outcomes (loneliness, depressive mood, and perceived stress) were assessed using self-reported measures. Associations between smartphone screen time and mental health were examined using weighted logistic regression, yielding weighted odds ratios (wORs) and 95% confidence intervals (CIs). We further examined socio-demographic and behavioral subgroups that were particularly vulnerable. RESULTS: Among 231,292 participants (48.92% girls), daily smartphone use was 8.39% for 4 hours per day. Adolescents using smartphones for >4 hours per day had higher odds of loneliness (wOR, 1.43 [95% CI, 1.36- 1.51]), depressive mood (1.31 [1.26-1.37]), and perceived stress (1.11 [1.07-1.16]) than those using smartphones for