摘要:Background: The aim of this study was to compare the effects of olanzapine versus haloperidol to control the signs and symptoms of stuttering. Methods: Ninety-three patients were recruited in a 12-week single-blind randomized clinical trial, which was held between October 2009 and October 2010. Forty-three patients received olanzapine (5 mg/day) and 50 patients, haloperidol (2.5 mg/day). Before and after the study, they were evaluated by a speech pathologist by Van Riper's questionnaire. The data were analyzed using the SPSS version 16. T-test was used to compare the data between the two groups. Results: Mean of stuttering score (SD) before treatment was 4.67 (0.81) and 4.40 (1.14) in haloperidol and olanzapine groups, respectively ( P > 0.05). After treatment, the mean (SD) score was 2.87 (1.32) and 1.56 (0.71) in haloperidol and olanzapine groups, respectively ( P = 0.000). Conclusions: It seems that olanzapine does have better impact in controlling stuttering, and it may be recommended to prescribe olanzapine for stutters as the first choice to control the stuttering under a careful follow-up.