Tardive dystonia.

This paper provides an overview of the phenomenology, epidemiology, and treatment of tardive dystonia. Tardive dystonia is one of the extrapyramidal syndromes that starts after long-term use of dopamine receptor antagonists. The diagnosis is based on the presence of chronic dystonia, defined as a syndrome of sustained muscle contractions, frequently causing twisting and repetitive movements or abnormal postures. Furthermore, dystonia must develop either during or within 3 months of a course of antipsychotic treatment, and other causes such as Wilson's disease, acute dystonia, or a conversion reaction must be ruled out. Tardive dystonia occurs in about 3 percent of patients on long-term antipsychotic treatment. Some probable risk factors for tardive dystonia are younger age, male, and the presence of tardive dyskinesia. The treatment of tardive dystonia starts with an evaluation of the need for using the causative drug. If antipsychotics must be continued, a switch to an atypical antipsychotic, particularly clozapine, may be helpful. If the dystonia is relatively localized, botulinum toxin is an effective but not well-known treatment possibility. If tardive dystonia is more extensive, either dopamine-depleting drugs or high dosages of anticholinergics can be tried.