Background: While the atypical antipsychotics should ultimately reduce the prevalence of tardive dyskinesia, it is likely to remain a significant clinical problem for a long time to come. No strategy has clearly emerged as the treatment of choice for tardive dyskinesia. Atypical antipsychotics have reduced propensities for producing acute extrapyramidal symptoms (EPS) and possibly tardive dyskinesia and may be effective in treating patients with established tardive dyskinesia.
Method: This 12-month, randomized, investigator-blinded study compared the efficacy of quetiapine (N = 22) and haloperidol (N = 23) in treating patients with DSM-IV schizophrenia or schizoaffective disorder and established tardive dyskinesia. Dyskinesia was assessed using the Extrapyramidal Symptom Rating Scale (ESRS) dyskinesia subscale scores and the Clinical Global Impression (CGI) dyskinesia scores. Other EPS, weight, serum prolactin level, and glycosylated hemoglobin level were also assessed. Subjects were enrolled in the study between April 2000 and March 2002.
Results: Mean endpoint doses were 400 mg/day of quetiapine and 8.5 mg/day of haloperidol. Compared with the haloperidol group, the quetiapine group showed significantly greater improvements in ESRS dyskinesia (6 and 9 months [p <or=.01]) and CGI dyskinesia (from 6 months onward [p <.05] and with repeated-measures analysis [p =.002]). Response rate (>or= 50% symptom reduction) was greater with quetiapine than haloperidol (64% [9/14] and 37% [6/16] at 6 months; 55% [6/11] and 28% [4/14] at 12 months). Other EPS decreased significantly with quetiapine at 3 (p =.01), 6 (p =.01), and 9 (p =.002) months. Serum prolactin levels decreased with quetiapine but increased with haloperidol, differing significantly between the groups at endpoint (p =.005). No significant changes in weight or glucose metabolism were recorded in either group.
Conclusion: Quetiapine effectively reduces the severity of tardive dyskinesia and is well tolerated in patients with established tardive dyskinesia.