Tardive dystonia: late-onset and persistent dystonia caused by antipsychotic drugs.

It is not widely recognized that antipsychotic drugs can cause late-onset and persistent dystonia. This dystonia, which we call tardive dystonia, is to be distinguished from acute dystonic reactions, which are transient, and from classic tardive dyskinesia, which is a choreic disorder that predominantly affects the oral region. We present 42 patients with tardive dystonia. The age of onset of dystonia was 13 to 60 years. Symptoms began after 3 days to 11 years of antipsychotic therapy. Younger patients tended to have more generalized dystonia. In a few patients, spontaneous remission occurred, but dystonia persisted for years in most. Therapy was rarely a complete success. The most frequently helpful medications were tetrabenazine (68% of patients improved) and anticholinergics (39% improved).