Condition: Schizophrenia

The purpose of this study is to evaluate the efficacy and safety of MK-8189 at a range of doses (8 mg, 16 mg, and 24 mg once daily) in adult participants who have an acute episode of schizophrenia according to Diagnostic and Statistical Manual of Mental Disorders 5th Edition (DSM-5) criteria. The primary hypotheses are the following: (1) MK-8189 24 mg is superior to placebo in reducing the Week 6 mean change from baseline in Positive and Negative Syndrome Scale (PANSS) total score (2) MK-8189 16 mg is superior to placebo in reducing the Week 6 mean change from baseline in PANSS total score.

With Amendment 4, enrollment was changed to approximately 500 participants with removal of the MK-8189 8 mg treatment arm. Participants enrolled before Amendment 4 that have been assigned to 8 mg MK-8189 will remain on 8 mg MK-8189 per protocol.