Movement disorders associated with atypical antipsychotic drugs.

Data from clinical trials reviewed in this article fulfill predictions based on preclinical findings that atypical antipsychotic drugs are associated with a reduced potential for inducing extrapyramidal symptoms (EPS) and other movement disorders. Atypical drugs have been shown to reduce all subtypes of acute EPS, the frequency of EPS-related patient dropouts, and the need for concomitant antiparkinsonian drug use. Clozapine remains superior to other atypicals in treating psychosis without worsening motor symptoms in patients with Parkinson's disease. Atypicals may be selectively advantageous in treating schizophrenic patients with a predisposition to catatonia. Although the risk of developing lethal neuroleptic malignant syndrome may be diminished with atypical drugs, clinicians must remain alert to the signs of this disorder. Atypicals have reduced liability for inducing tardive dyskinesia (TD) and show antidyskinetic properties in patients with preexisting TD. Passive resolution of TD may be facilitated in some patients by the use of these agents. Thus, the risk of movement disorders has become only one of several considerations in choosing among antipsychotic drugs.