Neuroleptic drug exposure and incidence of tardive dyskinesia: a records-based case-control study.

BACKGROUND With the introduction of atypical neuroleptic medications into the marketplace, the use of conventional neuroleptics has fallen, attendant with the perception of a more favorable side-effect profile for the atypical neuroleptics. OBJECTIVE The purpose of this study was to determine the risk of tardive dyskinesia (TD) associated with atypical and conventional neuroleptics. METHODS Subjects were adult users of the Veterans Administration Puget Sound Health Care System (VA-PSHCS) who received >or=1 prescription for neuroleptic medications during the study period. Electronic medical and pharmacy records were used to obtain neuroleptic drug exposure, exclusionary diagnosis, diagnosis for TD, and select demographic data. Medical records were reviewed to collect demographic data not available electronically. Controls were randomly selected from a cohort of neuroleptic users without TD. The case-defining event was the diagnosis of TD. RESULTS There were 42 cases and 160 controls for the final analysis. The only demographic difference found was a higher proportion of Caucasians (90%) in the TD group compared to the control group (76%). There was no significant difference in the risk of TD for patients on conventional neuroleptics compared to the atypical neuroleptic users (OR=1.29; 95% CI=0.71-2.34). After adjusting for age, gender, race, schizophrenia, schizoaffective disorder, depression, and anti-Parkinson drugs, there was still no significant difference in risk of TD between cases and controls (OR=1.02; 95% CI=0.465-2.232). CONCLUSION This study did not find a statistically significant difference in the risk of TD for users of conventional neuroleptics versus users of atypical neuroleptics.