Preferred intensity exercise for adolescents receiving treatment for depression: A pragmatic randomised controlled trial

Background: Exercise has been shown to be effective in treating depression, but trials testing the effect of exercise for depressed adolescents utilising mental health services are rare. The aim of this study was to determine the effectiveness of a preferred intensity exercise intervention on the depressive symptoms of adolescents with depression. Methods: We randomly assigned 87 adolescents who were receiving treatment for depression to either 12 sessions of aerobic exercise at preferred intensity alongside treatment as usual or treatment as usual only. The primary outcome was depressive symptom change using the Children's Depression Inventory 2^nd Version (CDI-2) at post intervention. Secondary outcomes were health-related quality of life and physical activity rates. Outcomes were taken at baseline, post intervention and at six month follow up. Results: CDI-2 score reduction did not differ significantly between groups at post-intervention (est. 95 % CI -6.82, 1.68, p = 0.23). However, there was a difference in CDI-2 score reduction at six month follow-up in favour of the intervention of -4.81 (est. 95 % CI -9.49, -0.12, p = 0.03). Health-related quality of life and physical activity rates did not differ significantly between groups at post-intervention and follow-up. Conclusions: There was no additional effect of preferred intensity exercise alongside treatment as usual on depressive reduction immediately post intervention. However, effects were observed at six months post-intervention, suggesting a delayed response. However, further trials, with larger samples are required to determine the validity of this finding.