Christian Pieter Hoffmann

First meta-analysis of the most authoritative studies: Adolescents' use of social media accounts for less than 1% of their subsequent symptoms of depression and anxiety. Most of the empirical investigations into social media use and mental health symptoms have utilized cross-sectional designs or have shown small effects, leading to scepticism in the field. More conclusive evidence could be synthesized from the full range of more robust longitudinal and experimental designs. Experimental designs are required to draw conclusions regarding causal relationships. Longitudinal designs afford conclusions regarding the direction of effects over time. To the best of our knowledge, this is the first review [and meta-analysis] to comprehensively synthesize longitudinal and experimental evidence on the association between time and frequency of social media use and mental health symptoms. We identified a considerably higher number of longitudinal papers than in a previous review. The key findings of this review and meta-analyses were that the relationships effects between time and frequency of social media use and depression and anxiety symptoms were statistically significant but relatively weak The time spent by young people using social media accounts for less than 1% of their subsequent symptoms of depression and anxiety. There is no evidence that this effect increases as age decreases. Reducing time spent on social media by young people is unlikely to be effective in preventing the worsening of their symptoms of depression and anxiety. Given the very weak relationships between social media use and the severity of anxiety and depression symptoms, social media use is unlikely to account for the contemporary youth mental health crisis. In relation to policy implications, a relationship between duration and frequency of social media use on subsequent anxiety and depression is not a solid basis for the rationale for age-related legal restrictions on social media.