Tardive dyskinesia and atypical antipsychotic drugs.

Typical antipsychotic agents produce central nervous system effects, especially extrapyramidal symptoms (EPS) and tardive dyskinesia (TD). Nearly every patient who receives neuroleptic therapy has one or more identifiable risk factors for TD, among the most significant of which are older age, female gender, presence of EPS, diabetes mellitus, affective disorders, and certain parameters of neuroleptic exposure (i.e. dose and duration of therapy). The typical course of TD is a gradual onset after several years of drug therapy, followed by slow improvement or remission, but a large number of patients have persistent TD with irreversible symptoms. In the management of TD, the patient's mental status is of primary concern. Currently, no uniformly safe and effective therapies for TD exist, though a variety of therapeutic agents, including some of the atypical neuroleptics, have been reported to treat TD successfully in some patients. Because TD liability is so much lower with novel antipsychotic therapy, all patients who have TD or are at risk for TD, as well as EPS, should be considered candidates for switching to these new drugs.