Executive Dysfunction in Geriatric Depression
Kathryn A. Lockwood, Ph.D. George S. Alexopoulos, M.D. Wilfred G. van Gorp, Ph.D.
Objective: The purpose of this study was to characterize the neuropsychological presentation of geriatric depression and to determine whether depression-related e xe c u ti ve d y s fu n c ti on is mo re p ro nounced during advanced age. Method: Theattention and executive functioning of 40 adults with major depression were compared with those of 40 healthy comparison subjects; 20 subjects were 20–60 years old, and 20 were ≥61 years. It was hypothesized that depressed subjects, regardless of age, would perform more poorly than comparison subjects on both attention and executive tasks but that the older depressed adults would evidence significantlygreater impairment on executive measures. Results: A significant interaction between age and depressive status was noted for tasks of executive functioning, while no age-depression interaction was found for tasks of selective or sustained attention. Older depressed adults demonstrated the slowest psychomotor speed and the poorest performance on tasks requiring set shifting, problem solving, andinitiation of novel responses. Conclusions: Patients with late-life depression have significant impairment in executive functioning. These findings can guide the development of stimulated functional neuroimaging paradigms that may clarify the pathophysiology of geriatric depression. Timely identification of attentional and executive processes fundamental to the daily functioning of depressed olderadults may lead to compensatory strategies that will improve the outcomes of late-life depression. (Am J Psychiatry 2002; 159:1119–1126)
europsychological deficits are a potential part of the clinical presentation in late-life depression. Geriatric depression has been associated with impairment in shortterm memory (1), visuospatial skills (2, 3), and psychomotor functioning (1). Studies ofgeriatric patients with major depression have documented disturbances in executive functioning (3–5), including impaired planning, organizing, initiating, sequencing, shifting, information processing speed, and working memory. A review of the literature revealed inconsistent findings regarding executive deficits in depression and suggests that frontal impairment varies according to age and depressionseverity (6). Severely depressed older adults have been found to evidence impairment in set shifting, verbal fluency, psychomotor speed, recognition memory, and planning on the Cambridge Neuropsychological Test Automated Battery (7). In another study using the same battery (8), moderately depressed middle-aged patients demonstrated deficits in planning, strategy development, spatial working memory,and verbal fluency despite exhibiting intact set shifting ability and psychomotor speed. In yet another study (9), severe depression was associated with deficits in set shifting but intact verbal fluency. Despite some equivocal findings in the literature, it is generally accepted that while performance on tasks requiring development of performance strategies may suffer in depressed patients,automatic processes are relatively preserved (10).
Am J Psychiatry 159:7, July 2002
Although focal deficits or even severe global impairment are observed in some depressed elderly patients, the cognitive functioning of others remains intact. This variation may result from the biologic heterogeneity of depression. Studies of the cognitive response to psychopharmacological treatment of late-lifedepression indicate that a substantial number of patients continue to experience residual signs of the disorder, including neuropsychological deficits. Persisting mild memory and executive impairment have been observed in elderly depressed patients who achieved remission with antidepressant treatment (4). Recently, one of us (11) proposed that depressive symptoms and executive impairment...