ABSTRACT
Objective: The current study examined cognitive function, major depressive disorder (MDD), and apathy construct symptoms in a large multi-site surveillance study of chronic fatigue syndrome conducted by the Centers for Disease Control and Prevention. Method: Subjects underwent neuropsychological testing and were administered the Diagnostic Interview Schedule to establish psychiatric diagnoses. Questions in the Beck Depression Inventory relating to motivation were used to develop an apathy construct. Results: Neuropsychological test results showed impairment in multiple cognitive domains in over 25% of the cohort, and raised proportions of outliers in motor and executive function. Memory complaints were not associated with tests of memory function. The apathy construct rather than MDD was associated with impaired cognition. Conclusions: Impaired cognition in chronic fatigue does not appear to be associated with MDD but rather with endorsement of construct symptoms. Similar associations were reported in medical conditions with known etiologies. These results suggest a potential biological basis for apathy construct symptoms.