Study to Evaluate Efficacy and Safety of Roluperidone in Adult Subjects With Negative Symptoms and Stable Positive Symptoms of Schizophrenia and to Evaluate the Relapse Rate of Roluperidone and Antipsychotic Medications

Evaluate the efficacy, as well as safety and pharmacokinetics, of Roluperidone in improving the negative symptoms of schizophrenia in adult subjects in Phase A of study, followed by Phase B of study to evaluate the relapse rate of Roluperidone and antipsychotic medications.

Inclusion Criteria: * Subject and subject's legal representative, if applicable, provided informed consent prior to the initiation of any study related procedures, and the subject is judged by the investigator as being capable of understanding the study requirements. * Male or female, 18 to 55 years of age, inclusive, and body mass index (BMI) \ 2 × ULN, or alkaline phosphatase \> 1.5 × ULN), or physical examination not resolved by the Baseline visit which according to Investigator can interfere with study participation. * Safety laboratory results from the Pretreatment Phase show one or more of the following: potassium \< 3.4 mmol/L, calcium \< 2.07 mmol/L, or magnesium \< 0.70 mmol/L. * Current systemic infection (e.g., Hepatitis B, Hepatitis C, human immunodeficiency virus \[HIV\], tuberculosis). A subject with positive Hepatitis B core antibody test and negative Hepatitis B Surface Antigen (HBsAg) may be included in the study if aminotransferase levels (alanine aminotransferases/ serum glutamate pyruvate transaminase \[ALT/SGPT\] and aspartate aminotransferase/ serum glutamic oxaloacetic transaminase \[AST/SGOT\]) do not exceed 2 × ULN. * Requires or may require concomitant treatment with any other medication likely to increase QT interval (e.g., paroxetine, fluoxetine, duloxetine, amiodarone). * Requires medication inhibiting CYP2D6. * Clinically significant ECG abnormality that could be a safety issue in the study, including QT interval value corrected for heart rate using the Fridericia's formula (QTcF) \> 430 msec for males and \> 450 msec for females. * Familial or personal history of long QT syndrome or with another risk factor for Torsade de Pointes. * History of myocardial infarction based on medical history or ECG findings at Screening. * Syncope. * Woman of child-bearing potential, or man, who is unwilling or unable to use accepted methods of birth control. * Woman with a positive pregnancy test, is lactating, or is planning to become pregnant during the study. * Participated in another clinical study that was completed within 6 months prior to Screening or has previously participated in \> 2 clinical studies with experimental medication within the past 2 years.