An Efficacy and Safety Study of Long Acting Injectable Risperidone and Oral Risperidone in Participants With Schizophrenia or Schizoaffective Disorder

This is a randomized (treatment group assigned by chance), open-label (all involved people know the identity of the study drug), active-controlled study to evaluate the improvement in social functioning among participants with schizophrenia taking LAI risperidone and oral risperidone tablet. The study drug will be administered for 52 weeks in flexible dose (range as per Investigator's discretion) and a total of 11 assessment visits will be conducted per participant, including Screening. The participant may be withdrawn from the trial for any medical reason at the sole discretion of the investigator. Before starting the study treatment, participants undergo the period of switching from the previous medication to risperidone for 4 weeks, and then they will be evaluated for tolerability for 2 weeks (run-in period for stabilizing to risperidone). In this 2-week period, participants will take oral risperidone. The efficacy will be primarily evaluated through Personal and Social Performance Scale. Safety will be evaluated through Abnormal Involuntary Movement Scale, Barnes Akathisia Rating Scale, and Simpson-Angus Rating Scale. Participants' safety will be monitored throughout the study.

Inclusion Criteria: - Participants who will understand the objectives and necessary procedures of the study and have signed the informed consent form which specified that they were willing to participate in the study - Participants with schizophrenia or schizoaffective disorder requiring long-term antipsychotic drug therapy - Participants with pre-morbid global assessment of functioning score of 71 or higher at Screening - Participants who do not present clinically significant abnormality in biochemistry and electrocardiography - Participants who will be compliant with the study requirements (that is, filling in the questionnaire by themselves) and who are capable of actually performing and willing to implementing them Exclusion Criteria: - Participants who had taken clozapine for the past three months - Participants with mental retardation (Intelligence Quotient less than 70 at the screening) - Participants with history of or currently with a serious disease (cardiovascular, respiratory, neurological \[including seizures or significant cerebrovascular\], renal, hepatic, hematologic, endocrine, immunologic or other systemic disease) including clinically relevant abnormal level - Participants who have an allergic or hypersensitive reaction to risperidone or who are unresponsive to risperidone - Pregnant or lactating female participants