The authors longitudinally evaluated the cognitive functions of patients with probable Alzheimer's disease who also met criteria for major depression and compared them with matched patients with Alzheimer's disease who were not depressed. They found no significant difference in the pattern of neuropsychological deficits between the two groups; composite scores on attention, language, memory, learning, and visuospatial functions did not differentiate the two groups at baseline or at 1-year follow-up. The results of this preliminary report suggest that depression does not modify the neuropsychological features and the rate of progression of Alzheimer's disease.