There are 5 phases in this study: a screening phase (lasting up to 7 days) to establish a subject's eligibility for the study,; a 3-week double-blind acute treatment phase to treat the acute or manic episode; a 12-week double-blind treatment continuation phase to establish a patient's clinical stability,; a double-blind treatment maintenance phase to measure the time to symptom recurrence that will last until the patient experiences a recurrence,; and a follow-up phase consisting of a visit approximately 1 week after the last study visit. All antipsychotic drugs and all mood stabilizers other than study drug must be discontinued before the first study drug administration.