Physical activity and mental health in children and adolescents: An updated review of reviews and an analysis of causality

Objectives: Evidence concerning physical activity and mental health remains less well documented for children and adolescents. An updated review of systematic reviews and meta-analyses was undertaken concerning physical activity and mental health in children and adolescents, and to judge the extent to which associations can be considered causal. Methods: Systematic reviews and meta-analyses were identified to update our previous review of reviews (Biddle & Asare, 2011), with papers identified between November 2010 and the end of 2017. Criteria were used to judge causality (Hill, 1965), including strength of association, dose-response association, and experimental evidence. Results: Since 2011, the quantity (k = 42 reviews) and quality of research has increased in depression (evidence from 10 reviews), self-esteem (10 reviews) and cognitive functioning (25 reviews). Anxiety had only three new, small, reviews. Intervention effects for depression are moderate in strength while observational data show only small or null associations. Variable effect sizes are evident from interventions for the reduction of anxiety and improvement in self-esteem. Higher or improved fitness and physical activity are associated with better cognitive health and performance. There was partial support for a causal association with depression, a lack of support for self-esteem, but support for cognitive functioning. Conclusions: There are significant increases in research activity concerning physical activity and depression, self-esteem, and cognitive functioning in young people. The strongest evidence for a causal association appears to be for cognitive functioning, and there is partial evidence for depression.