Bipolar Disorder I or II With a Major Depressive Episode

The purpose of this study is to assess antidepressant efficacy differences between ALTO-100 and placebo during the Double-Blind period in patients with bipolar disorder I or II with current major depressive episode, when used adjunctively to a mood stabilizer and/or atypical antipsychotic, related to patient characteristics. Additionally, safety, tolerability, and efficacy will be assessed in a subsequent open label treatment period.