Add-On Therapy to Risperidonein Schizophrenia

Add-On double-blind study treatment commenced at randomization for 11 weeks while patients were continuing open-label risperidone. Randomization was immediately preceded by a one week open-label Risperidone-Only Treatment period. Patients who were receiving antipsychotics medication(s) at screen other than risperidone alone was withdrawn from previous non-risperidone medication(s) and at the same time commenced risperidone in titrating doses over a week. This Antipsychotic Switch-Over Period occurred between Screen and Risperidone-Only Treatment period. Patients remained hospitalized for at least during the Risperidone-Only treatment Period and first week of Add-On treatment Period.