RESUMO
Knowing the clinical differences of olanzapine, quetiapine, and risperidone would be of benefit for choosing an atypical antipsychotic drug. In order to compare their efficacy and acceptability, we conducted a meta-analysis of published, randomized, placebo-controlled trials by comparing the response and dropout rates of an atypical antipsychotic drug group and those of a placebo group. After a comprehensive search of study reports, the response and dropout rates of patients treated with an atypical antipsychotic drug and those treated with placebo were extracted on the intention-to-treat basis. The effect size with 95 per cent confidence interval (CI) of pooled data comparing the response and dropout rates of an atypical antipsychotic drug group and those of a placebo group were calculated by using the Peto method. The response-rate effect sizes (95% CIs) of olanzapine, quetiapine, and risperidone were 1.75 (1.06 to 2.89), 1.71 (1.20 to 2.42), and 3.28 (1.98 to 5.44), respectively. The dropout-rate effect sizes (95% CIs) of olanzapine, quetiapine, and risperidone were 0.55 (0.35 to 0.88), 0.65 (0.46 to 0.91), and 0.39 (0.24 to 0.62), respectively. In conclusion, olanzapine, quetiapine, and risperidone are more effective and more acceptable than placebo in treating schizophrenic patients. However, they are not different from each other in the respect of efficacy and acceptability. The cost of these agents should play an important role in choosing an atypical antipsychotic drug.