A Comparative Study of Paliperidone Palmitate and Risperidone Long Acting Injection (LAI) in Participants With Schizophrenia

The purpose of this study is to compare the efficacy of paliperidone palmitate and risperidone long acting injection (LAI) in participants with schizophrenia (psychiatric disorder with symptoms of emotional instability, detachment from reality, often with delusions and hallucinations, and withdrawal into the self) along with safety and tolerability.

This is a randomized (assigned by chance), open-label (all people know the identity of the intervention), active-controlled, parallel-group (a medical research study comparing the response in two or more groups of participants receiving different treatments), multicenter (when more than one hospital or medical school team work on a medical research study) comparative study in participants with schizophrenia. This study comprises a screening period of not more than 7 days and a 13-week open-label treatment period. Paliperidone palmitate will be administered as intramuscular injection (injection of a substance into a muscle) of 150 milligram equivalent (mg eq.) at baseline, 100 mg eq. at Day 8, flexible dose on Day 36 (50 or 100 mg eq.) and on Day 64 (50, 100 or 150 mg eq.) depending on investigator's discretion. Risperidone LAI will be administered at a dose of 25 mg at Day 8 and Day 22, flexible dose on Day 36 (25 or 37.5 mg) and Day 64 (25, 37.5, or 50 mg). Dose on Day 50 is the same as Day 36 and dose on Day 78 is the same as Day 64. Participants will receive oral risperidone tablets (1 to 6 mg/day) for the first 4 weeks of the open-label treatment period. Each participant may receive oral risperidone tablets (1 to 2 mg daily) for up to 3 weeks at Day 36 and Day 64 if the dose of risperidone LAI was increased on Day 36 and Day 64. Efficacy will primarily be assessed using the Positive and Negative Syndrome Scale (PANSS). Participants' safety will also be assessed.

Eligibility Criteria:
Inclusion Criteria:

* Participants who meet diagnostic criteria for schizophrenia according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) (disorganized type \[295.10\], catatonic type \[295.20\], paranoid type \[295.30\], residual type \[295.60\], or undifferentiated type \[295.90\]) for at least 1 year before screening and prior medical records, written documentation, or verbal information obtained from previous psychiatric providers obtained by the investigator must be consistent with the diagnosis of schizophrenia
* A total Positive and Negative Syndrome Scale (PANSS) score between 60 and 120, inclusive, at screening and baseline
* Body mass index (BMI) of equal to or greater than 17.0 kilogram per meter square (kg/m\^2)
* Female participants must be postmenopausal for at least 2 years, surgically sterile, abstinent, or, if sexually active, be practicing an effective method of birth control before study entry and throughout the study
* Be capable of self-administering study medication (applies to oral supplementation) or have assistance with study medication administration consistently available throughout the first 4 weeks of the study Exclusion Criteria:
* A primary, active DSM-IV diagnosis on Axis I other than schizophrenia
* A decrease of at least 25 percent in the total PANSS score between screening and baseline
* Participants who have previously participated in this study
* A DSM-IV diagnosis of active substance dependence within 3 months before screening (nicotine and caffeine are not exclusionary)
* History of treatment resistance as defined by failure to respond to 2 adequate treatments with different antipsychotic medications (an adequate treatment is defined as a minimum of 6 weeks at maximum tolerated dosage)