The author discusses four topics: (1) Age-related alterations in central nervous system function predispose elderly patients to increased risk of psychotropic drug toxicity. (2) Age-related alterations in psychotropic drug pharmacokinetics lead to decreased metabolism, increased volume of distribution, and decreased clearance. (3) Treatment of depression in the elderly with a special focus on selection of drugs and toxicity. Four classes of drugs are reviewed: cyclic antidepressants, atypical antidepressants, monoamine oxidase inhibitors, and stimulants. and (4) Treatment of anxiety. Recommendations for benzodiazepine and buspirone use are given, and benzodiazepine toxicity in the elderly is reviewed in detail.