Do exercise trials for adults with depression account for comorbid anxiety? A systematic review

Background: Depression and anxiety are more likely to co-occur than to occur in isolation. Research supports the use of exercise in the treatment of depression or anxiety, but comorbidity may complicate how people are impacted by treatment. Methods: A systematic review (PROSPERO # 42018111114) was conducted to investigate whether and how the evidence of effects of exercise on depression accounts for (1) the prevalence of comorbidity of depression and anxiety within trial samples, and (2) the effects of comorbidity in analyses of intervention effects. This review will utilize and extend the findings of Cooney et al. (2013) applying the same search terms and inclusion criteria (i.e. depression diagnosis). For the review update, five databases were searched including Cochrane Register of Control Trials, Embase, PubMed, Medline and PsycINFO. Results: The search resulted in 63 eligible studies with a total of 4,816 participants. Sixteen (25%) studies reported prevalence of anxiety, two (3%) considered comorbidity descriptively, but none accounted for comorbidity in their trial analyses. Conclusions: Depression and anxiety are known to co-exist but trials testing the effects of exercise on depression are generally neither reporting the prevalence of comorbidity of anxiety within their samples nor testing whether the presence of comorbidity impacts trial effectiveness and efficacy. Comorbidity of depression and anxiety should be considered in exercise trials to ensure that the effects will apply to the manifestation of these disorders in the real world. © 2020 Elsevier Ltd