**Study Overview:** This study aims to test a new medicine called NBI-1117568 to see if it can help prevent schizophrenia symptoms from coming back in adults. Schizophrenia is a mental illness that can cause changes in thinking, feeling, and behavior. The study compares the medicine to a placebo, which is a pill with no active medicine, to check its effectiveness. **Key Criteria:** - Adults with schizophrenia who have responded well to other antipsychotic medicines (except clozapine) can join. - Participants should not have severe uncontrolled health conditions or have been in a psychiatric hospital for a long time recently. - Participants can't have started or changed therapy treatments just before or during the study. **Important Points:** - **Duration and Visits:** Participants will first receive open-label treatment, then be observed for relapse prevention. - **Compensation:** There might be potential compensation for participation. - **Risks:** Possible risks include those typical for new medicine trials, such as side effects or no improvement in symptoms.

Note: Detailed criteria and other conditions apply. Consult with the study team for more information.