A Study To Evaluate The Effect Of A Supratherapeutic Dose Of MK-8189 On The QTc Interval In Participants With Schizophrenia (MK-8189-019) (TQT)

Inclusion Criteria: Meets diagnostic criteria for schizophrenia or schizoaffective disorder according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria. Is in the non-acute phase of their illness. Has a history of receiving and tolerating antipsychotics medication within the usual dose range employed for schizophrenia. Participants with hypothyroidism, diabetes, high blood pressure, chronic respiratory conditions or other medical conditions could be considered if their condition is stable. Exclusion Criteria: History of a primary DSM-5 axis I psychiatric diagnosis other than schizophrenia or schizoaffective disorder per the allowed DSM-5 criteria. History of intellectual disability, borderline personality disorder, anxiety disorder, or organic brain syndrome. History of neuroleptic malignant syndrome or moderate to severe tardive dyskinesia (TD). History of seizure disorder beyond childhood or is receiving treatment with any anticonvulsant to prevent seizures. History of cancer. History or presence of sick sinus syndrome, atrioventricular (AV) block, myocardial infarction, pulmonary congestion, cardiac arrhythmia, prolonged QTc interval, or conduction abnormalities. History of risk factors for Torsades de Pointes (e.g., heart failure/cardiomyopathy or family history of long QT syndrome). History of frequent syncope, vasovagal episodes, or epileptic seizures. Family history of sudden cardiac death. Has a positive test(s) for hepatitis B surface antigen (HBsAg), hepatitis C antibodies or human immunodeficiency virus (HIV). Had major surgery, donated, or lost 1 unit of blood within 4 weeks prior to the pre-study visit.