KEY INCLUSION CRITERIA:

• Acute exacerbation of schizophrenia as defined by: subject recently hospitalized or is in the process of being admitted to a hospital or an acute care inpatient psychiatric treatment facility; and has a PANNS Total score of 70 or greater at the time of screening and at randomization based on a 1-7 point scale; and has a score on any two of the four items from psychosis cluster of the BPRS (extracted from the PANSS) that correspond to the positive symptoms (hallucinatory behavior, unusual thought content, conceptual disorganization and suspiciousness) totaling 8 or greater; and has a total of 6 or greater on one of the following two pairs of items from the BPRS (extracted from the PANSS): hostility and uncooperativeness or excitement and tension.
• Current DSM-IV-TR diagnosis of schizophrenia as confirmed by the SCID
• Positive response to antipsychotics in the previous 2 years

KEY EXCLUSION CRITERIA:

• Current diagnosis of schizoaffective disorder, drug-induced psychosis, manic episode or major depressive episode.
• At the time of screening, has been hospitalized for more than 14 days for the current episode
• Has ever taken clozapine
• Has had more than 3 psychiatric hospitalizations in the previous 6 months or has had more than 8 weeks of psychiatric hospitalization in the previous 12 months
• Has serious violent, homicidal, suicidal ideation
• Has received depot medications fluphenazine decanoate and/or haloperidol decanoate within 2 or 4 weeks prior to randomization respectively
• Urine toxicology screen is positive for phencyclidine (PCP), opiates, cocaine or amphetamines
• History of alcohol or substance dependence within the past month
• Has taken any valproate product for a psychiatric indication within the previous 30 days
• Has received an investigational drug within the last 30 days