title: The effect of exercise on depressive symptoms in multiple sclerosis based on a meta-analysis and critical review of the literature.
abstract: OBJECTIVE
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Section of Sport Science, Department of Public Health, Aarhus University, Aarhus, Denmark.
authors.forename: U
authors.initials: U
authors.lastname: Dalgas
authors.forename: E
authors.initials: E
authors.lastname: Stenager
authors.forename: M
authors.initials: M
authors.lastname: Sloth
authors.forename: E
authors.initials: E
authors.lastname: Stenager
mesh_terms: D003863:Depression / Q000628:therapy*; D005081:Exercise Therapy / Q000379:methods*; D006801:Humans; D009103:Multiple Sclerosis / Q000523:psychology*
keywords: depression; exercise therapy; training