A study to evaluate the safety and efficacy of treatment with MK8998 as compared to placebo and olanzapine for acutely psychotic patients with schizophrenia.

• Drug: MK8998
  MK8998 6 mg capsules twice daily with food on Days 1 through 7. On Day 8, dosage will be changed to 8 mg capsules twice daily. Treatment period of 4 weeks. There will be a period of time when all patients will receive placebo.
• Drug: Comparator: olanzapine
  olanzapine 5 mg tablets twice daily with food on Days 1 through 7. On Day 8, dosage will be increased to 5 mg tablets in the morning and 10 mg tablets in the evening. Treatment period of 4 weeks. There will be a period of time when all patients will receive placebo.
• Drug: Comparator: Placebo
  Placebo tablets matching olanzapine tablets and MK8998 twice daily with food for a treatment period of 14 days. There will be a period of time when all patients will receive placebo.

• 1: Experimental
  MK8998
  Intervention: Drug: MK8998
• 2: Active Comparator
  olanzapine
  Intervention: Drug: Comparator: olanzapine
• 3: Placebo Comparator
  Placebo Comparator
  Intervention: Drug: Comparator: Placebo

Inclusion Criteria:

• Patient's age is 18 to 55
• Patient meets DSM-IV/DSM-IV-TR criteria for a primary diagnosis of schizophrenia
• The duration of the patients schizophrenia diagnosis must be greater than 1 year
• Patient has an acute exacerbation of psychotic symptoms (of at least 3 days but no longer than 6 weeks) and marked deterioration of function

Exclusion Criteria:

• Patient currently has a clinically significant neurological, metabolic, hepatic, renal, hematological, pulmonary, cardiovascular, gastrointestinal, and/or urological disorder that would pose a risk to the patient in the opinion of the investigator if they were to participate in the study or that might confound the results of the study
• The patient has evidence of acute hepatitis, clinically significant chronic hepatitis, or impaired hepatic function
• The patient has a chronic organic disease of the central nervous system (other than schizophrenia) such as, tumors, inflammation, active seizure disorder, vascular disorder, Parkinson's disease, Alzheimer's disease or other forms of dementia, myasthenia gravis, or other degenerative processes. In addition, patients must not have a history of mental retardation or persistent neurological symptoms attributable to serious head injury
• Patient has a history of alcohol/drug dependence within 3 months or alcohol/drug abuse within 1 month of screening. Exceptions include caffeine and nicotine abuse/dependence
• Patient has a history of hypersensitivity to olanzapine OR poor response to olanzapine in the last 2 years OR intolerable side effects due to olanzapine OR patients current psychotic relapse occured while consistently taking a therapeutic dose (10 mg or more) of olanzapine OR olanzapine is medically contradicted
• Patient is refractory to antipsychotic treatment