1. Have a current diagnosis of schizophrenia.
2. Increase in symptoms over the past 2-4 weeks.
3. Willing to remain inpatients for the duration of the trial.
1. Evidence or history of clinically significant medical problems.
2. Females of childbearing potential.
3. A primary psychiatric diagnosis other than schizophrenia.
4. A diagnosis of substance abuse or dependence in the last 6 months.