Preliminary studies suggested that the therapeutic dose of risperidone should be between 2 and 4 mg/day for Chinese schizophrenia patients (28, 29). The Guidelines for the Prevention and Treatment of Schizophrenia in China (6) recommend 2–6 mg/day as the therapeutic dose of risperidone for Chinese patients, a lower figure than the recommendation for their Caucasian counterparts (30). Therefore, the mean risperidone dose (4.3 mg) used in the acute phase before study entry was sufficiently high according to Chinese standards