A Study of MK-5720 in Participants With Schizophrenia (MK-5720-001)

Prior treatment

• Has a history of seizure disorder beyond childhood or is receiving treatment with any anticonvulsant to prevent seizures
• Has a metallic implant of any sort that prevents MRI examination, or any other contraindication to MRI examination
• Has received or is currently receiving treatment with clozapine for any length of time
• Has received any live vaccines within 30 days prior to the first dose of study intervention or is scheduled to receive any live vaccine through 60 days following study intervention

Other illness

• Has history of mental retardation, borderline personality disorder, or organic brain syndrome
• Has a history of neuroleptic malignant syndrome or moderate to severe tardive dyskinesia
• Has a substance-induced psychotic disorder or behavioral disturbance thought to be due to substance abuse
• Has a family history of sudden death
• History of significant multiple and/or severe allergies or has had an anaphylactic reaction or significant intolerability to prescription or nonprescription drugs or food
• Positive test(s) for hepatitis B surface antigen (HBsAg), hepatitis C antibodies or human immunodeficiency virus (HIV)

Other

• The main exclusion criteria include but are not limited to the following:
• Is at imminent risk of self-harm, based on clinical interview and responses on the Columbia-Suicide Severity Rating Scale (C-SSRS), or of harm to others in the opinion of the investigator
• Has claustrophobia to a degree that prevents tolerance of magnetic resonance imaging (MRI) scanning procedure
• Presents any concern by the investigator regarding safe participation in the study or for any other reason the investigator considers the participant inappropriate for participation in the study

• The main inclusion criteria include but are not limited to the following:
• Meets diagnostic criteria for schizophrenia or schizoaffective disorder according to the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) criteria with the onset of the first episode being no less than 2 years prior to screening and monotherapy with antipsychotics for treatment should be indicated
• Has a history of receiving and tolerating antipsychotics medication within the usual dose range employed for schizophrenia
• Can discontinue the use of all antipsychotic medication at least 5 days or 3 half-lives (which ever in longer) prior to the start of the treatment period and during the study