Comorbid anxiety corresponds with neuropsychological dysfunction in unipolar depression.

INTRODUCTION: Unipolar depressives seem apt to show neuropsychological impairment, particularly involving executive function and memory. Yet, not all depressed patients show such deficits. Major depressive illness shares a high rate of comorbid anxiety disorder, and anxiety disorders also tend to correspond with cognitive difficulties. Consequently, depressed individuals with comorbid anxiety disorders may be inclined to demonstrate greater neuropsychological dysfunction than those without anxiety disorders.
METHOD: We compared nonpsychotic depressed inpatients with (n=22) and without comorbid anxiety disorders (n=30) to a group of control subjects (n=38) on a brief but broad battery of neuropsychological tests. Patients were tested during an inpatient admission, and data were collected retrospectively from available records.
RESULTS: Both groups of depressed patients showed worse memory function than the controls. Yet, executive dysfunction and psychomotor slowing were specific to the depressed group with comorbid anxiety. The comorbid anxiety group also had more impaired scores than either the nonanxious depressed group or the control group. The depressed group without a comorbid anxiety disorder demonstrated no significant slowing compared to the control group.
CONCLUSIONS: Major depressive disorder corresponds with significant memory impairment, regardless of comorbid anxiety disorder. Yet, presence of a comorbid anxiety disorder coincides with deficits involving executive function and psychomotor slowing. Clinical and theoretical relevance of the data is discussed.