Prevalence of tardive dyskinesia among three ethnic groups of chronic psychiatric patients.

The relationship between prevalence of tardive dyskinesia and ethnicity (black, white, or Hispanic) was examined in a group of 491 chronic psychiatric patients at a large state psychiatric hospital in California. Overall, the prevalence of tardive dyskinesia was 17.7 percent. No significant differences in the prevalence of tardive dyskinesia or in neuroleptic dosage levels were found among the three groups. A relationship was found between lower prevalence of tardive dyskinesia and higher current neuroleptic dosage, suggesting that higher dosage masks symptoms of tardive dyskinesia.