Inclusion Criteria:

• Male or female inpatients or outpatients, 10-17 yrs of age, who have not reached their 18th birthday prior to screening. Patient must weigh at least 20kg at screening.
• Must meet diagnostic criteria for current major depressive episode of Bipolar I Disorder according to the Diagnostic and Statistical Manual of Mental Disorders, DSM-IV-TR, and confirmed by Kiddie Schedule for Affective Disorders and Schizophrenia for School Aged Children-Present and Lifetime (K-SADS-PL)
• Patients entering the study will also be scored by the CDRS R (entry score of greater than or equal to 40) as well as the adolescent-structured YMRS (entry score of less than or equal to 15 with YMRS Item 1 [elevated mood] score less than equal to 2).

Exclusion Criteria:

• Patients will be excluded if they are, in the opinion of the investigator, actively suicidal
• Have an acute, serious or unstable medical condition
• Have clinically significant laboratory abnormalities
• Have had one or more seizures of unclear etiology
• Have a current or lifetime diagnosis of any of the following according to DSM-IV criteria: Schizophrenia, Schizophreniform Disorder, Schizoaffective Disorder, Delusional Disorder, Psychotic Disorder Not Otherwise Specified, Delirium of any type, Amnestic Disorder, any Substance-Induced Disorder, or any Psychotic Disorder due to a General Medical Condition, unless there is substantive reason to believe patient was misdiagnosed