The effect of exercise on depressive symptoms in multiple sclerosis based on a meta-analysis and critical review of the literature.

BACKGROUND AND PURPOSE

The purpose of this study was to perform a systematic review of the literature on the effects of exercise on depressive symptoms in patients with multiple sclerosis (MS), as well as to apply meta-analytical procedures to the results.

METHODS

A systematic search covering eight databases was conducted. The included studies were randomized controlled trials applied to people with definite MS who completed a structured exercise intervention which were compared to any comparator, including other forms of exercise. The outcomes included a primary measure of depression/depressive symptoms or an instrument with a clearly defined depression subscale.

RESULTS

Fifteen randomized controlled trial studies were identified including a total of 331 exercising subjects and 260 controls. The average Physiotherapy Evidence Database (PEDro) score was 5.6 ± 1.3 points. Only one study applied depressive symptoms as the primary outcome. Four studies showed positive effects of exercise on depressive symptoms. An in-depth analysis of the studies revealed that the baseline level of depressive symptoms, patient disability level, choice of depression instrument and exercise intensity may influence the results. The meta-analysis included 12 studies reflecting a total of 476 subjects. The standardized mean difference across studies was g = -0.37, 95% confidence interval (-0.56; -0.17), and the null hypothesis of homogeneity within the sample could not be rejected (Q = 12.05, df = 11, P = 0.36).

DISCUSSION

Exercise may be a potential treatment to prevent or reduce depressive symptoms in individuals with MS, but existing studies do not allow solid conclusions. Future well-designed studies evaluating the effects of exercise on depressive symptoms and major depression disorder in MS are highly warranted.