Fatigue, depression, and physical activity in relapsing-remitting multiple sclerosis: Results from a prospective, 18-month study

Abstract Background Fatigue, depression, and physical inactivity are common in multiple sclerosis (MS), but there is limited information on the bi-directional associations among those variables over a long period of time. Objective This study examined the hypothesis that fatigue and depression would predict change in physical activity and that physical activity would predict changes in fatigue and depression over an 18-month period of time in persons with MS, even after controlling for disability status, disease duration, sex, and age. Methods This longitudinal study collected data on fatigue, depression, physical activity, and confounding variables from the same sample of persons with relapsing-remitting MS on two occasions that were separated by 18 months. Results The cross-lagged path coefficient between baseline fatigue and follow-up physical activity was statistically significant (path coefficient=−.26, p