According to a recent review of reviews it is concluded that while awaiting further high quality trial evidence it would seem appropriate for exercise to be recommended in combination with other treatments. This cautious conclusion should be that exercise is more effective than no treatment and that for mild to moderate depression it is efficacious and for severe depression it should be added to other treatments in the treatment program.
Let’s have a look at the evidence. Until the nineties of the previous century research and reviews were mainly based on non-randomized controlled trials unpublished dissertations and observational studies and their results should be interpreted with caution. Until 2006 some additional reviews were published which included randomized controlled trials (RCTs) only. One review involved 11 RCTs and another review mainly focused on the elderly. The first one showed a very large treatment effect in favor of exercise compared to control conditions. In the elderly exercise is efficient in reducing depression or high levels of depressive symptoms. Overall quality of the RCTs improved over time encouraging the optimism about the efficacy of exercise for depression.
Since 2006 four RCTs have examined the effects of exercise on depression.
- Patients with moderate to severe depression on antidepressants were randomized to walking or placebo low intensity stretching and relaxation.
After 10 days, reduction in depression scores in the walking group was significantly larger than in the placebo group. In addition, the proportion of patients with a clinical response was greater for the walking group.
- In a pilot RCT exercise significantly reduced minor depression relative to sertraline in older adults.
- In another study depressed patients were randomized to one of four conditions; supervised exercise in a group setting, home based exercise, standard antidepressant treatment (sertraline) or placebo pill for 16 weeks. At 4-month follow-up patients receiving active treatments tended to have higher
remission rates than the placebo controls.
- In a recent study participants with elevated levels of depression (n = 23) were randomized to low frequency exercise (one aerobic session per week and deemed the comparator), individualized high frequency exercise (3–5 aerobic exercise sessions per week) or group based high frequency exercise interventions. Participants randomized to the high frequency exercise interventions reported lower depression scores than those assigned to the low frequency exercise intervention at 8-week follow-up. This might mean that the exercise and depression relationship may be dose dependent. there was no significant difference in improvement between the group exercise or individual program perhaps suggesting that the additional effects of exercising in a group are not important in the relationship between exercise and depression.
There are several RCTs of the impact of exercise on depression ongoing, in the near future the effects and costs of exercise for depression treatment might be even more clear. Until than I will put my money in favor of exercise as treatment for depression or additional treatment. What do you think?
Daley, A. (2008). Exercise and Depression: A Review of Reviews Journal of Clinical Psychology in Medical Settings, 15 (2), 140-147 DOI: 10.1007/s10880-008-9105-z