Overdiagnosis of dementia.

Accurate diagnosis of the dementias is difficult. Of 100 patients referred to a specialized outpatient dementia clinic, at least 26 were not demented. Fifteen had depression, 7 had miscellaneous other neuropsychiatric disorders, and 4 were normal. Specialized dementia clinics help to improve diagnostic accuracy. Three diagnostic errors appeared particularly important: failure to recognize depression, especially in the presence of mild organic brain disease; equating brain atrophy on the computerized tomogram with clinical dementia; and failure to distinguish focal from global intellectual impairment. For confirmation, the diagnosis of dementia requires follow-up evaluation, brain biopsy, or autopsy.