1. Serious medical or neurological illness (unstable cardiac disease, seizure disorder, malignancy, liver or renal impairment, etc.)

2. Current substance abuse

3. Pregnancy, nursing, or unwilling to use appropriate birth control measures during participation if female and fertile

4. Unable to complete neuropsychological tests

5. History of serious blood dyscrasia requiring discontinuation of clozapine

6. Serious suicidal or homicidal risk within the past six months

Trial of Ampakine Added to Clozapine, Olanzapine or Risperidone in Patients With Schizophrenia