Exercise for depression

Mead GE, Morley W, Campbell P, Greig CA, McMurdo M, Lawlor DA

Published Online:

January 20, 2010

Depression is a common and important illness affecting at least 1 in 5 people during their lifetime. Exercise has been advocated as an adjunct to usual treatment. This review identified all available randomised trials which compared exercise with either no treatment or an established treatment (e.g. talking therapy) for people with a clinical diagnosis of depression. Data from 25 trials were combined. We found exercise did seem to improve the symptoms of depression, but we cannot be sure exactly how effective it is, or the most effective type of exercise. The evidence suggests that exercise probably needs to be continued in the longer-term for benefits on mood to be maintained.

Abstract (click to read)

Background:

Depression is a common and important cause of morbidity and mortality worldwide. Depression is commonly treated with antidepressants and/or psychotherapy, but some people may prefer alternative approaches such as exercise. There are a number of theoretical reasons why exercise may improve depression.

Objectives:

To determine the effectiveness of exercise in the treatment of depression.

Search strategy:

We searched Medline, Embase, Sports Discus, PsycINFO, the Cochrane Controlled Trials Register, and the Cochrane Database of Systematic Reviews for eligible studies in March 2007. In addition, we hand-searched several relevant journals, contacted experts in the field, searched bibliographies of retrieved articles, and performed citation searches of identified studies. We also searched www.controlled-trials.com in May 2008.

Selection criteria:

Randomised controlled trials in which exercise was compared to standard treatment, no treatment or a placebo treatment in adults (aged 18 and over) with depression, as defined by trial authors. We excluded trials of post-natal depression.

Data collection and analysis:

We calculated effect sizes for each trial using Cohen's method and a standardised mean difference (SMD) for the overall pooled effect, using a random effects model. Where trials used a number of different tools to assess depression, we included the main outcome measure only in the meta-analysis.

Main results:

Twenty-eight trials fulfilled our inclusion criteria, of which 25 provided data for meta-analyses. Randomisation was adequately concealed in a minority of studies, most did not use intention to treat analyses and most used self-reported symptoms as outcome measures. For the 23 trials (907 participants) comparing exercise with no treatment or a control intervention, the pooled SMD was -0.82 (95% CI -1.12, -0.51), indicating a large clinical effect. However, when we included only the three trials with adequate allocation concealment and intention to treat analysis and blinded outcome assessment, the pooled SMD was -0.42 (95% CI -0.88, 0.03) i.e. moderate, non-significant effect. The effect of exercise was not significantly different from that of cognitive therapy. There was insufficient data to determine risks and costs.

Authors' conclusions:

Exercise seems to improve depressive symptoms in people with a diagnosis of depression, but when only methodologically robust trials are included, the effect sizes are only moderate and not statistically significant. Further, more methodologically robust trials should be performed to obtain more accurate estimates of effect sizes, and to determine risks and costs. Further systematic reviews could be performed to investigate the effect of exercise in people with dysthymia who do not fulfil diagnostic criteria for depression.

This record should be cited as:

Mead GE, Morley W, Campbell P, Greig CA, McMurdo M, Lawlor DA. Exercise for depression. Cochrane Database of Systematic Reviews 2009, Issue 3. Art. No.: CD004366. DOI: 10.1002/14651858.CD004366.pub4

Assessed as up to date:

March 26, 2007

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Primary Review Group:

Depression, Anxiety and Neurosis Group

PEARLS - Practical Evidence About Real Life Situations (click to read)

Clinical question:

How effective is exercise in the treatment of depression?

Bottom line:

Exercise seems to improve depressive symptoms in people with a diagnosis of depression. However, when only methodologically robust trials were included, the effect sizes were only moderate and not statistically significant. The effect of exercise was not significantly different from that of cognitive therapy.

Caveat:

The majority of trials had methodological weaknesses. The number of comparison groups ranged from 2 to 6, and there was wide variation in the type and duration of exercise intervention. The review was unable to be sure how effective exercise is as treatment for people with depression, what constitutes the most effective type of exercise (aerobic, resistance or mixed), whether group or individual exercises are better, or the optimum duration of exercise. There were insufficient data to determine risks and costs.

Context:

Depression is a common illness, affecting at least 1 in 5 people during their lifetime. Exercise has been advocated as an adjunct to usual treatment.

Cochrane Systematic Review:

Mead GE et al. Exercise for depression. Cochrane Reviews 2008, Issue 4. Article No. CD004366. DOI: 10.1002/14651858.CD004366.pub3. This review contains 28 trials involving 1599 participants. Twenty five trials provided data for meta-analyses.

Authored by:

Brian R McAvoy

Cochrane Primary Health Care Field

Health topics:

Mental health > Depression > Depressive disorders & major depression

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