Maintenance Phase (Weeks 15 - 38; Days 99 - 266) Patients that have shown adequate response to risperidone long acting will continue into the maintenance phase of the study. From this point onwards, the treating physician may change the dosage of risperidone long acting at any time as considered necessary. Temporary oral supplementation will also be permitted during the maintenance phase when considered by the treating physician to be clinically necessary for the treatment of breakthrough psychosis. Apart from the above, the treating physician is not restricted from adding or discontinuing any pharmacological treatment (including another antipsychotic) deemed necessary for the clinical management of the subject.