Clinical and epidemiologic aspects of tardive dyskinesia

The prevalence of tardive dyskinesia appears to parallel the risk of spontaneous dyskinesia unrelated to neuroleptic treatment. Prevalence, corrected for spontaneous dyskinesia, averages 15%-20%; incidence is estimated at 2%-5% per year but appears to be highest between 6 and 24 months after initiation of neuroleptic treatment. No type of neuroleptic agent has proven more or less likely to be associated with tardive dyskinesia, nor is there a firm relationship between risk and mean dosage or total drug exposure. Factors contributing to individual vulnerability to tardive dyskinesia or spontaneous dyskinesia, other than advancing age, are not well-established. However, it is reasonable to assume that more rational and conservative clinical use of neuroleptic agents may reduce the risk of tardive dyskinesia and other toxic effects. Many chronically psychotic patients can be maintained on doses only 10%-20% of those in common use. Spontaneous remission of tardive dyskinesia after treatment discontinuance is common, although it may not occur for many months. Safe and effective treatments of tardive dyskinesia, as well as new, nonneurotoxic antipsychotic agents, are required.