Why is this review important?
Depression is a common and disabling illness, affecting over 100 million people worldwide. Depression can have a significant impact on people’s physical health, as well as reducing their quality of life. Research has shown that both pharmacological and psychological therapies can be effective in treating depression. However, many people prefer to try alternative treatments. Some NHS guidelines suggest that exercise could be used as a different treatment choice. However, it is not clear if research actually shows that exercise is an effective treatment for depression.
Who may be interested in this review?
Patients and families affected by depression.
Mental health policy makers.
Professionals working in mental health services.
What questions does this review aim to answer?
This review is an update of a previous Cochrane review from 2010 which suggested that exercise can reduce symptoms of depression, but the effect was small and did not seem to last after participants stopped exercising.
We wanted to find out if more trials of the effect of exercise as a treatment for depression have been conducted since our last review that allow us to answer the following questions:
Is exercise more effective than no therapy for reducing symptoms of depression?
Is exercise more effective than antidepressant medication for reducing symptoms of depression?
Is exercise more effective than psychological therapies or other non-medical treatments for depression?
How acceptable to patients is exercise as a treatment for depression?
Which studies were included in the review?
We used search databases to find all high-quality randomised controlled trials of how effective exercise is for treating depression in adults over 18 years of age. We searched for studies published up until March 2013. We also searched for ongoing studies to March 2013. All studies had to include adults with a diagnosis of depression, and the physical activity carried out had to fit criteria to ensure that it met with a definition of ‘exercise’.
We included 39 studies with a total of 2326 participants in the review. The reviewers noted that the quality of some of the studies was low, which limits confidence in the findings. When only high-quality trials were included, exercise had only a small effect on mood that was not statistically significant.
What does the evidence from the review tell us?
Exercise is moderately more effective than no therapy for reducing symptoms of depression.
Exercise is no more effective than antidepressants for reducing symptoms of depression, although this conclusion is based on a small number of studies.
Exercise is no more effective than psychological therapies for reducing symptoms of depression, although this conclusion is based on small number of studies.
The reviewers also note that when only high-quality studies were included, the difference between exercise and no therapy is less conclusive.
Attendance rates for exercise treatments ranged from 50% to 100%.
The evidence about whether exercise for depression improves quality of life is inconclusive.
What should happen next?
The reviewers recommend that future research should look in more detail at what types of exercise could most benefit people with depression, and the number and duration of sessions which are of most benefit. Further larger trials are needed to find out whether exercise is as effective as antidepressants or psychological treatments.