NOVEL ANTIPSYCHOTICS, EXTRAPYRAMIDAL SIDE-EFFECTS AND TARDIVE-DYSKINESIA

A common and serious drawback of the conventional antipsychotics is th eir association with a range of motor disturbances: acute extrapyramid al symptoms, including parkinsonism, acute akathisia and acute dystoni a; and chronic motor problems such as tardive dyskinesia, chronic akat hisia and tardive dystonia. In addition to physical disability directl y related to abnormal movements, the acute movement disorders can caus e considerable subjective discomfort and distress, and are frequently cited as a reason for poor compliance with medication, at least during acute treatment. They can also confound clinical assessment of mental -state phenomena because of symptom overlap with the psychotic illness being treated. The results of clinical trials of the newer antipsycho tic drugs such as clozapine, risperidone, olanzapine, amisulpride, que tiapine and sertindole suggest a lower liability for acute extrapyrami dal symptoms than conventional antipsychotic drugs such as haloperidol and chlorpromazine. The relative liability of each of the newer drugs to cause acute extrapyramidal side effects is not known, as they have been available for a relatively short time and there is a paucity of direct comparative studies. Evidence is accumulating that those patien ts exhibiting acute extrapyramidal side effects are at greater risk of developing tardive dyskinesia, which raises the hope that the newer a ntipsychotic drugs may also be associated with less tardive dyskinesia in the longer term. Encouraging data are already available for clozap ine, which appears to have a low incidence of tardive dyskinesia, and therapeutic value in a proportion of established cases of tardive dysk inesia and tardive dystonia. Here me review the available data on atyp ical antipsychotics and adverse motor effects. Int Clin Psychopharmaco l 13 (suppl 3):S49-S57 (C) 1998 Lippincott-Raven Publishers.