Efficacy of NBI-1117568 in Preventing Relapse in Adults With Schizophrenia

Key Inclusion Criteria: * Participant has a primary diagnosis of schizophrenia established by a comprehensive psychiatric evaluation based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR) criteria. * Participant had the initial diagnosis of schizophrenia ≥1 year before screening. * Participant has had a positive response to ≥1 antipsychotic therapy (other than clozapine) at a therapeutic dose. Key Exclusion Criteria: * Participant has an unstable or poorly controlled medical condition or chronic disease (including history of neurological \[including dementing illness, myasthenia gravis\], hepatic, renal, cardiovascular, gastrointestinal, pulmonary, autoimmune, or endocrine disease that may affect study participation or results) or malignancy within 30 days before Day 1. * Participant has any laboratory abnormalities suggestive of clinically significant, poorly managed, or unmanaged undiagnosed disease. * Participant has a history of clozapine treatment for treatment-resistant psychosis. * Participant has a history of a stay in a psychiatric inpatient facility for ≥30 consecutive days (other than for purely social reasons or due to participation in a different clinical trial) during the 90 days before screening. * Participant has initiated or increased intensity of nonpharmacological psychosocial therapeutic treatment within 3 weeks before screening or is expected to change throughout the length of the study. Note: Other protocol-defined Inclusion and Exclusion criteria may apply.