Haas et al examined flexible doses of risperidone 1–3 mg/day or risperidone 4–6 mg/day relative to a placebo control group.16 The primary efficacy measure was a baseline-to-end point change in the PANSS total score. Significant improvement was found in both risperidone groups versus placebo. Generally, adverse events were more common in the risperidone groups (75% and 76%) versus placebo (54%). More specifically, risperidone 4–6 mg/day compared with risperidone 1–3 mg/day had higher incidences of extrapyramidal disorder (39% versus 33%), dizziness (14% versus 7%), and hypertonia (14% versus 5%). No prolactin-related adverse events occurred.