Clock tests in depression, Alzheimer's disease, and elderly controls

OBJECTIVE: While clock-drawing tests are commonly used to screen for cognitive impairment in the elderly, little is known about the performance of elderly depressives. METHODS: We compared thirty-three patients with major depression to forty-two Alzheimer's disease and thirty age-matched controls on clock-drawing, copying, and reading. RESULTS: Patients with Alzheimer's disease had significantly lower scores on clock-drawing, copying, and reading than patients with depression or the controls (p < 0.05). Patients with depression did not differ significantly from controls on quantitative scores or qualitative errors. CONCLUSIONS: Clock tests may be useful for identifying depressed patients with underlying dementia.