The effects of social media on adolescent mental health: Findings from a population-based cohort study in Australia

Background: There are growing concerns about the potential contribution of social media use on rising levels of adolescent mental health problems, but our understanding of this relationship remains poor. The current study examined the effects of social media on future mental health problems (depressive symptoms, anxiety symptoms, poor wellbeing, and self-harm), in adolescents aged 12 to 18 years; considering overall and sex-stratified effects, and differences across age (early, middle, and late adolescence). Methods: We used data from a prospective longitudinal study (Child to Adult Transition Study). Participants in CATS were recruited through schools in Melbourne, selected using a stratified random sampling approach. A cohort of Grade 3 students (N=1,239) participated in wave 1 in 2012 and have since completed annual surveys. The current analysis used data up to wave 11. Exposure was self-reported duration of daily social media use from waves 4 to 10 (12 to 18 years). Outcome was self-reported depressive symptoms, anxiety symptoms, wellbeing, and self-harm from waves 5 to 11 (13 to 19 years). Findings: Across adolescence, >2 hrs versus <1 hr of daily social media use was associated with a small increased risk of high depressive symptoms at the subsequent annual wave (risk difference of 5 per 100), with larger estimates in females than males. Females also had increased risk for poor wellbeing at the subsequent wave. Risk differences for anxiety and self-harm were negligible across adolescence. For females, estimated risks for all mental health problems were larger in early adolescence (12 to 13 years) compared to later ages, but no such differences were apparent across age for males. Interpretation: Higher levels of social media use were associated with small increases in future risk of high depressive symptoms across adolescence. Largest risks of mental health problems were observed during early adolescence in females, supporting the need to consider policies that mitigate the adverse effects of social media on the mental health of younger adolescents.