Physical Activity Moderates the Association Between Pain and Depressive Symptoms Among Persons with Multiple Sclerosis.

Objective: The present study examined physical activity as a possible moderator in the relationship between pain and depressive symptoms among persons with multiple sclerosis (PwMS).

Method: Fifty-three PwMS completed a comprehensive neuropsychological test battery and psychosocial questionnaires. Pain was operationalized as a composite of measures from the Brief Pain Inventory. Metabolic equivalents (METs) of energy expended during self-reported vigorous activity (VA), moderate activity (MA), and walking, as well as global physical activity which combined the three, were derived from the International Physical Activity Questionnaire-Short Form. Self-reported physical activity was measured using the Cognitive Health Questionnaire Exercise Scale. Regressions on depressive symptoms (Beck Depression Inventory-Fast Screen) examining both conceptualizations of physical activity, pain, and their interactions were explored.

Results: Regression analyses revealed that interactions between pain and each measure of global physical activity were significant (p = .01). Simple effects tests revealed that pain only influenced depressive symptoms in PwMS with low global physical activity METs (p < .001) and low overall self-reported physical activity (p < .001). The separate interactions between pain and METs during self-reported VA, MA, and walking on depressive symptoms were not significant.

Conclusion: We found that global physical activity moderated the relationship between pain and depressive symptoms in MS. Specifically, pain influenced depressive symptoms in PwMS who engaged in less overall physical activity. These results highlight the importance of screening PwMS for pain and suggest that behavioral interventions aimed at increasing overall lifestyle physical activity may be useful in improving depressive outcomes in PwMS with pain.