Fatigue Moderates the Relationship between Negative Attributional Style and Depression Symptoms in Multiple Sclerosis

Abstract Objective To investigate whether fatigue moderates the relationship between negative attributional style and depression symptoms in persons with Multiple Sclerosis (PwMS). Method Forty-seven PwMS (39 Female) completed a comprehensive neuropsychological test battery and psychosocial questionnaires. The Attributional Style Questionnaire was utilized to create internal, stable, and global attribution dimension scores, and an overall attributional style score combining the three dimensions. Overall, physical, psychosocial, and cognitive fatigue were measured using the Fatigue Impact Scale (FIS). The Beck Depression Inventory-Fast Screen was used to measure depression symptoms. Separate regressions with depression symptoms as the outcome were conducted with attributional style, each type of fatigue, and their interactions included as predictors. Results Regression analyses revealed that the interaction between attributional style and overall fatigue significantly predicted depression symptoms (p = 0.049). Simple effects tests showed that overall attributional style significantly predicted depression symptoms when overall fatigue was high (p = 0.008). The interactions between attributional style and both physical fatigue (p = 0.003) and psychosocial fatigue (p = 0.039) also significantly predicted depression symptoms. Simple effects tests showed that attributional style was associated with depression symptoms only in PwMS with high physical fatigue (p < 0.001) and high psychosocial fatigue (p = 0.018). Conclusions Fatigue moderated the relationship between overall attributional style and depression symptoms in PwMS. Specifically, attributional style was only significantly associated with depression symptoms in PwMS reporting high levels of overall, physical, and psychosocial fatigue. Interventions aimed at targeting fatigue may reduce the risk that negative attributional style will lead to depressive symptoms in MS.