Inclusion Criteria:  Subject is male or female, aged 18 to 65 years for DB treatment part. Subject reads, understands, and signs an Institutional Review Board (IRB)/Independent Ethics Committee (IEC)-approved current ICF prior to performing any of the Screening procedures Diagnosis schizophrenia  Exclusion Criteria:  Has a history of treatment resistance exhibited by any of the following:  No or minimal response to at least 2 periods of treatment lasting 28 days or longer, with antipsychotic agents at the maximally tolerated dose. Lifetime history of clozapine use History of electroconvulsive therapy (ECT) for treatment of schizophrenia within the past 5 years. Is treatment-naïve for schizophrenia. Primary current diagnosis other than schizophrenia or a comorbid diagnosis that is primarily responsible for the current symptoms and functional impairment. Has a current diagnosis of a psychotic disorder other than schizophrenia or a behavioral disturbance thought to be due to substance abuse disorder. Meets criteria for moderate-to-severe substance use disorder within past 6 months prior to Screening (excluding those related to caffeine or nicotine). Has a history of the following: (a) traumatic brain injury causing ongoing cognitive difficulties, Alzheimer's disease, or another form of dementia, or any chronic organic disease of the central nervous system (CNS) (b) intellectual disability of a severity that would impact ability to participate in the study. Subject has a current primary DSM-5 diagnosis other than schizophrenia, including schizoaffective disorder, major depressive disorder, post-traumatic stress disorder, obsessive-compulsive disorder, manic episode, hypomania, panic disorder, delirium, amnestic or other cognitive disorders. Also, subjects with borderline, paranoid, histrionic, schizotypal, schizoid, or antisocial personality disorder. On antipsychotic within the Screening Period (minimum 3 days prior to Baseline and throughout the study). Within 28 days prior to Baseline: monoamine oxidase (MAO) inhibitors, CNS stimulants, potent CYP3A4/5 enzyme-inducing drugs including but not limited to rifampin and carbamazepine and strong CYP3A4/5 inhibitors like ketoconazole, itraconazole, clarithromycin, etc. (see Appendix 20.1 for prohibited medications). Antipsychotic depot medication within 5 half-lives prior to Baseline. Positive Urine Drug Screen for drugs of abuse, including amphetamines, barbiturates, cocaine, ecstasy, phencyclidine or opiates meeting criteria of moderate-to-severe DSM-5 substance use disorder.