The prevalence and burden of the dementia syndrome are high after age 65. The majority of patients with early dementia are undiagnosed in primary care practices. A brief interview screen can detect dementia with reasonable accuracy. Pharmacologic and nonpharmacologic treatments show benefit on outcomes in mild to moderate Alzheimer's disease, but it is not clear how many subjects in these studies were detected by screening. Evidence for benefit of treatment for other etiologies of dementia syndrome is more limited than that for Alzheimer's disease.