Should we recommend exercise to adolescents with depressive symptoms? A meta-analysis.

There is growing interest in the potential role of exercise in the reduction of depressive symptoms. The aim of this meta-analysis was to examine whether exercise reduces depressive symptoms amongst depressed adolescents. The following databases were searched on 30 January 2015: MEDLINE, PsychINFO, SPORTDiscuss and PUBMED. Studies were included if they examined exercise interventions amongst adolescents with clinical levels of depressive symptoms, were published in peer-reviewed journals in the English language and contained a control/comparison group. Of 6631 retrieved studies, eight studies were included in the meta-analysis. Meta-analysis was conducted using a random effects model due to the high level of heterogeneity identified amongst studies ( I = 65.1, P < .005). The analysis revealed a moderate reduction in depressive symptoms post-intervention (Hedge's g = -0.61, P = .007). This analysis provides preliminary evidence that exercise is effective in reducing symptoms of depression among adolescents with clinical levels of depressive symptoms. The present meta-analysis, however, is limited by the generally low quality of included studies, high level of between-study heterogeneity and restriction of inclusion criteria to published studies. Further high-quality trials with depressed adolescents are needed to determine the efficacy of exercise in the reduction of depressive symptoms and the exercise parameters associated with the antidepressant effects of exercise.