Maintenance treatment of severe tardive dyskinesia with clozapine: 5 years' follow-up.

\Drug-induced tardive dyskinesia (TD) affects approximately 20% to 30% of schizophrenic patients. Although it is usually mild, from 1% to 8% of patients may develop severe TD. Second-generation antipsychotics have demonstrated a lower risk of inducing TD. However, despite the advances brought by second-generation antipsychotics, the treatment strategies for TD remain problematic, given both the lack of an established therapeutic choice and the need for long-term use of antipsychotics in the treatment of schizophrenia. Clozapine is an atypical antipsychotic with minimal risk of inducing TD. Furthermore, it has been suggested that clozapine might actually improve the symptoms of TD. Accordingly, we evaluated the effects of clozapine on severe TD over 5 years. Seven patients meeting Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition criteria for chronic exacerbated schizophrenia (mean age 28.5 +/- 10.2 years) and presenting severe TD, defined as Abnormal Involuntary Movements Scale score above 13, were treated with clozapine and followed up for 5 years. Extrapyramidal Symptoms Rating Scale assessment was performed in all patients at baseline, after 6 months and 3 and 5 years. Mean Extrapyramidal Symptoms Rating Scale scores decreased 83% after 3 years and 87.5% after 5 years. Mean dose for all patients was 428 +/- 269 mg/d after 5 years. Results from this open-label study suggest that clozapine may be a further option for the treatment of TD over long term.