Relationship Between Depression, Fatigue, Subjective Cognitive Impairment, and Objective Neuropsychological Functioning in Patients With Multiple Sclerosis

Objective: This study explored the influence of depression and fatigue on subjective cognitive complaints and objective neuropsychological impairment in patients with multiple sclerosis (MS). Methods: Data for this study were taken from a randomized controlled trial, comparing 16 weeks of telephone-administered cognitive-behavioral therapy and telephone-administered supportive emotion focused therapy for the treatment of depression. The sample includes 127 patients with MS. The following self-report measures were collected pre- and posttreatment: Perceived Deficits Questionnaire, Beck Depression Inventory-II, and Modified Fatigue Impact Scale. Measures of objective cognitive functioning and the Hamilton Rating Scale for Depression were administered over the telephone. Results: Our results showed that changes in depression and fatigue significantly predicted changes in subjective cognitive complaints from pre- to posttreatment, with patients perceiving fewer cognitive problems at posttreatment (beta = .36, p < .001 and beta = .61, p < .001, respectively). Changes in depression and fatigue were not significantly related to changes in objective neuropsychological performance. Improvements in depression and fatigue also predicted improved accuracy in perceiving cognitive abilities from pre- to posttreatment (OR = .77, p < .001 and OR = .90, p < .001, respectively). Conclusions: The results of this study suggest that improvements in depression and fatigue through treatment do not influence objective neuropsychological performance in MS patients, but do relate to changes in subjective impairment. Furthermore, these changes improve patients' abilities to accurately perceive their cognitive functioning.