Pharmacotherapeutic trials in tardive dyskinesia.

Some of the clinical factors contributing to the currently unsatisfactory state of therapy for tardive dyskinesia are reviewed. Problems such as lack of clear syndrome delineation and phenomenological description, the lack of standardization in rating scales and the lack of attention to trial design have all probably contributed to a rather confusing picture. Controlled trials suggest that several pharmacological agents may be of therapeutic value but that clinical prediction of an individual's response is impossible. The strategy of acute drug challenge has emerged as perhaps the most promising approach to the definition of pharmacological subtypes and therefore the choice of optimal treatment.