Depression and neuropsychological performance in the eosinophilia myalgia syndrome: A comprehensive analysis of cognitive function in a chronic Illness

Summary: The assessment of cognitive functioning in chronic medical illness is complicated by concurrent depression and medication use. Both can affect neuropsychological performance. We examined cognitive functioning and its relationship to depression and medication history in patients with eosinophilia myalgia syndrome (EMS). EMS is a multisystem disorder caused by the toxic effects of ingesting contaminated L-tryptophan. Patients with EMS (n = 48) were compared to healthy (n = 36) and depressed (n = 18) controls on neuropsychological measures and psychiatric interviews. EMS patients had significantly more fatigue than both control groups (p < 0.05) and performed significantly worse on verbal memory (p < 0.05) and visual search and attention (p < 0.05). Increased levels of depressive symptoms were associated with poorer verbal memory for EMS patients but not for the depressed control group. Medicated EMS patients had significantly more fatigue (p < 0.05) but did not differ in neuropsychological performance from nonmedicated EMS patients. The results of this study indicate that EMS patients are more cognitively impaired than healthy and depressed controls and that cognitive dysfunction in EMS cannot be attributed solely to medication or depression.