A randomized controlled trial of risperidone and olanzapine for schizophrenic patients with neuroleptic-induced tardive dyskinesia.

Objective: To compare the efficacy of risperidone and olanzapine in schizophrenic patients with tardive dyskinesia on treatment with first-generation antipsychotics. Method: We conducted a 24-week, raterblinded, flexible-dose study. Sixty patients with DSM-IV schizophrenia (n = 58) or schizoaffective disorder (n = 2) met the DSM-IV research criteria for neuroleptic-induced tardive dyskinesia and were randomly assigned to a risperidone or olanzapine group. The primary outcome was a comparison of the change in the total scores on the Abnormal Involuntary Movement Scale (AIMS) from baseline to study end point between the groups. The study was conducted from July 2000 to June 2004. Results: The mean±SD doses of risperidone and olanzapine from baseline to study end point were 1.9±0.7 to 4.1±1.4 mg/d and 8.1 ± 2.0 to 12.6±5.4 mg/d, respectively. There were no statistically significant differences in demographic data, severity of tardive dyskinesia, or psychotic symptoms between risperidone and olanzapine groups at baseline assessment. Both groups showed significant improvement in mean ± SD AIMS total scores (risperidone: -7.4±6.9, P<.0001 ; olanzapine: -6.2±8.0, P=.0002). However, there was a more statistically significant change in the slope of AIMS total scores in the risperidone group than in the olanzapine group (P=.0001). Conclusions: Our findings demonstrated that olanzapine may not have better potential for tardive dyskinesia improvement than risperidone did. Double-blinded, fixed dose studies with a larger sample size on schizophrenic patients with tardive dyskinesia from different ethnic groups are needed to confirm the results of our study.