Effect of Exercise on Depressive Symptoms in Multiple Sclerosis: A Meta-Analysis

Abstract

Background: Depression is debilitating and highly prevalent among adults with multiple sclerosis (MS). Exercise may reduce symptoms of depression; however, the different biases present in uncontrolled studies could overestimate, or underestimate, noted treatment effects. Aim: To review the available evidence for the effectiveness of exercise training targeted to MS based on the ‘gold’ standard randomised controlled trial. Methods: Fifteen independent studies, comprising a pooled sample of 544 adults with relapsing-remitting or progressive MS, were identified from the Cochrane Library, Embase, PEDro, PsycINFO, and PubMed databases. The methodological quality of included studies was assessed with the PEDro scale. Hedges’ g, fail-safe Ns, heterogeneity, and p-values were calculated using random effects modelling. The moderating effects of exercise type (aerobic vs. nonaerobic), exercise volume (i.e., total number of sessions), and baseline depression scores were additionally examined. Results: Most studies reported adequate methodological details, although blinding of participants and administering therapists were criteria unfulfilled. Exercise programs resulted in immediate and large improvements in mood (g = .79, 95% CI [.39, 1.19], p < .01). However, conclusions could not be drawn for longer-term effectiveness (g = -.18, 95% CI [-.50, .14], p = .28; Nstudies = 4). Univariate meta-regressions revealed a significant moderating effect for exercise volume. Depressed adults who took part in exercise programs also displayed significantly greater improvements than controls. Conclusion: Exercise efficacy for post-MS depression can be maximised by bolstering session volume and duration for those who are most prone to respond. The influence of exercise type on depression outcomes remains unclear.