A Call to Explore the Etiology of Depression Underlying the Report of Cognitive Concerns in Patients with Multiple Sclerosis

Background: Depression is known to strongly impact cognitive functioning, particularly initiation, spontaneous recall, and processing speed.  Core symptoms of depression that overlap with hallmark symptoms of Multiple Sclerosis (MS) include low mood, anhedonia, and fatigue, any of which could conceivably reduce performance on cognitive tasks.  However, understanding the etiology of cognitive symptoms may be important to developing effective and appropriate treatment interventions.

Objectives: This study presents an initial attempt to examine whether anhedonia or low mood, two symptoms that are routinely screened for in identifying patients who might be experiencing depression, are more strongly associated with report of cognitive concerns.

Methods: Data was collected on a sample of MS patients who were screened as part of routine care at an MS Clinic in the southeastern United States (N = 259, 79.5% female, 55% Caucasian, mean age = 46.67 years).  Cognitive concerns were subjectively reported.  Anhedonia and mood were assessed using the 2-item Patient Health Questionnaire for depression (PHQ-2; Kroenke, Spitzer, & Williams, 2003).

Results: Results from logistic regression show that anhedonia was not significantly associated with report of cognitive concerns (p = .718) and patients who reported depressed mood were 3.5 times more likely to report concerns with cognitive functioning (p = .006) than those denying mood complaint.

Conclusions: In light of these results, professionals may want to give greater consideration to interventions directly elevating mood, in the treatment of depression when cognition is also of concern, than to behavioral activation and stimulation.  Although anhedonia was not significantly related to cognitive concerns in this limited exploration, teasing apart anhedonia from fatigue may be advisable to uncover masked effects of anhedonia versus fatigue, as many patients commented during screening that their experience of anhedonia was driven by MS-related fatigue.  Providing an additional assessment of MS fatigue when anhedonia is endorsed may assist with further exploring etiology of depression and its relationship to cognitive functioning.