The clinical efficacy of present psychotherapeutic drugs varies among the various types. Antianxiety agents are most controversial, as a great many confounding, metapharmacological variables influence the results obtained. The use of such drugs in traditional doses and dosage schedules also may not employ them to best advantage. Antidepressants must increasingly be considered in relation to the clinical type of depressive reaction being treated. Tricyclic drugs are clearly indicated for retarded or endogenous depressions; in exceptional cases, monoamine oxidase inhibitors may merit a trial in such patients. Depressions characterized by much attendant anxiety may respond better to phenothiazines or to antianxiety agents. Consequently, the scope of “antidepressants” may be larger than simply one or two drug classes. Antipsychotics are clearly effective. A large number of peer drugs are available, although it seems clear that, for reasons still to be elucidated, individual patients may respond better to one than to another. Drug therapy of other types of psychiatric disorder, such as mental retardation, childhood and adolescent behavior disorders, alcoholism, and psychoses associated with old age, is of limited value. Lithium salts may represent a significant advance in the management and prevention of manic attacks.