INCLUSION CRITERIA:  Provides written informed consent to participate in this study Body mass index is between 18 to 40 kg/m2 Fluent English speaker Diagnosed with schizophrenia at least 1 year ago Psychiatrically stable schizophrenia with no more than moderate symptomatology On a stable atypical antipsychotic regimen Agrees to use effective contraception throughout the study and for at least 3 months afterward Agrees to avoid using tobacco/nicotine and caffeine for several hours at a time Agrees to not participate in another study of a drug or device while in this study  EXCLUSION CRITERIA:  Was in another study of a drug in the past 2 months Fails a drug/alcohol screen, including amphetamines, barbiturates, cocaine, marijuana, methadone, methamphetamine, 3,4 methylenedioxymethamphetamine (MDMA), phencyclidine, or nonprescribed benzodiazepines or opiates Has had a recent heavy smoking habit (>40 cigarettes/2 packs/day) or recently had nicotine replacement therapy Has significant heart disease Has hemophilia or any other bleeding/platelet dysfunction condition Has hepatitis or HIV  Additional inclusion and exclusion criteria apply, per protocol.