This is an open-label (all people know identity of intervention), randomized (the study drug is assigned by chance), multicenter (conducted in more than 1 center), and exploratory study in participants with schizophrenia (psychiatric disorder with symptoms of emotional instability, detachment from reality) or schizoaffective disorder (mixed psychiatric disorder relating to complex psychotic state that has features of both schizophrenia and mood disorder). Duration of this study will be 24 months. Study assessment visits will be conducted at Screening, Baseline, Week 2, every 4 weeks till Week 22, at Week 28, every 12 weeks till Week 88 and at Week 104. All eligible participants will receive either risperidone long acting injection 25 milligram (mg) intramuscularly (into the muscle) along with their current oral medication (atypical antipsychotic - risperidone, quetiapine, olanzapine) or only their current oral medication. Efficacy will be evaluated primarily by Positive and Negative Syndromes Scale (PANSS), time to relapse and Social and Occupational Functioning Assessment Scale (SOFAS). Participants's safety will be evaluated throughout the study mainly by Abnormal Involuntary Movement Scale (AIMS), Barnes Akathisia Rating Scale (BARS), and Simpson Angus Scale (SAS).
