Current diagnostic methods and outcome variables for clinical investigation of Alzheimer's disease.

The diagnosis of Alzheimer’s disease (AD) is done by a careful history, requiring reliable informants and serial observations. The main differential diagnosis is depression, delirium, and inappropriate use of psychotropic drugs. Other common causes of dementia such as vascular, Lewy body disease, frontal lobe degeneration, can be distinguished by the pattern of symptoms and findings on the physical examination. A minimal amount of laboratory investigation is usually required.