Incidence of tardive dyskinesia with atypical versus conventional antipsychotic medications: a prospective cohort study.

OBJECTIVE: Most previous studies of the incidence of tardive dyskinesia with atypical antipsychotics compared with conventional antipsychotics have not had tardive dyskinesia as their primary focus. The current study aimed to compare the incidence of tardive dyskinesia with atypical vs conventional antipsychotics using methods similar to those from a previous prospective cohort study at our site in the 1980s.

METHOD: Three hundred fifty-two initially tardive dyskinesia-free psychiatric outpatients (diagnosed at baseline using the Structured Clinical Interview for DSM-IV) were examined for a new diagnosis of tardive dyskinesia (using the Abnormal Involuntary Movement Scale and Glazer-Morgenstern criteria) every 6 months for up to 4 years at a community mental health center. At baseline, subjects were receiving conventional antipsychotics only (23%), atypicals only (64%), or both (14%). Only 26 subjects had never received conventional antipsychotics. Baseline evaluations were conducted from November 2000 through May 2003. Follow-ups were conducted through February 2005.

RESULTS: Compared with subjects treated with conventional antipsychotics alone since the previous visit, the adjusted tardive dyskinesia incidence rate-ratio for subjects treated with atypical antipsychotics alone was 0.68 (95% CI, 0.29-1.64). The incidence and prevalence of tardive dyskinesia was similar to previous findings at this site in the 1980s.

CONCLUSIONS: The incidence of tardive dyskinesia with recent exposure to atypical antipsychotics alone was more similar to that for conventional antipsychotics than in most previous studies. Despite high penetration of atypical antipsychotics into clinical practice, the incidence and prevalence of tardive dyskinesia appeared relatively unchanged since the 1980s. Clinicians should continue to monitor for tardive dyskinesia, and researchers should continue to pursue efforts to treat or prevent it.