COGNITIVE FUNCTIONS IN MAJOR DEPRESSION AND PARKINSON-DISEASE

Objective: To investigate the importance of major depression in the pr oduction of cognitive deficits in patients with Parkinson disease (PD) . Design: A comprehensive neuropsychological and psychiatric assessmen t was conducted in 19 patients with PD and major depression, 31 patien ts with PD without depression, 27 patients with major depression but w ithout PD, and 12 age-comparable healthy controls. Setting: Outpatient clinic. Results: Patients with major depression (with or without PD) had significantly more severe cognitive deficits than both healthy con trols and patients with PD without depression on tests of verbal fluen cy and auditory attention, while patients with PD and major depression had significantly more severe deficits on tasks of abstract reasoning and set alternation compared with the other 3 groups. Conclusions: Ma jor depression in patients with PD is associated with significant defi cits on specific cognitive tasks. While some of these deficits may be explained by the presence of major depression, frontal lobe-related co gnitive impairments may result from an interaction between neuropathol ogic factors in PD and the mechanism of major depression.