Risperidone Versus Olanzapine for Mania in Preschool Children 4 to 6 Years of Age With Bipolar Disorder

Inclusion Criteria: Male or female patients, 4-6 years of age. Parent or legal representative must have a level of understanding sufficient to communicate intelligently with the investigator and study coordinator, and to cooperate with all tests and examinations required by the protocol. Patients and their legal representative must be considered reliable. Each patient and his/her authorized legal representative must understand the nature of the study. The patient's authorized legal representative must sign an informed consent document. Patient must have a diagnosis of bipolar I or bipolar II disorder and currently displaying an acute manic, hypomanic, or mixed episode (with or without psychotic features) according to the DSM-IV based on clinical assessment and confirmed by structured diagnostic interview (Kidd Schedule of Affective Disorders). Patients must have an initial score on the Y-MRS total score of at least 15. Patient must be able to participate in mandatory blood draws. Exclusion Criteria: Investigator and his/her immediate family; defined as the investigator's spouse, parent, child, grandparent, or grandchild. Serious, unstable illness including hepatic, renal, gastroenterologic, respiratory, cardiovascular (including ischemic heart disease), endocrinologic, neurologic, immunologic, or hematologic disease Uncorrected hypothyroidism or hyperthyroidism. History of severe allergies or multiple adverse drug reactions. Non-febrile seizures without a clear and resolved etiology. Leukopenia or history of leukopenia without a clear and resolved etiology. Judged clinically to be at serious suicidal risk. Any other concomitant medication with primarily central nervous system activity other than specified in Concomitant Medication portion of the protocol History of intolerance or non-responder to risperidone, or olanzapine as determined by the principal investigator. Treatment with nonreversible monoamine oxidase inhibitor within 2 weeks prior to Visit 2. Current diagnosis of schizophrenia.