Additional Study Information: We are trying to understand what causes bipolar disorder and how medications treat bipolar depression. Particularly, we are looking at the importance of dopamine signaling in the process. If you participate, you will have two different brain scans (MRI and PET scan). You will also have treatment for your depression with an FDA approved medication, lurasidone (Latuda). The study is funded by the Columbia University Irving Institute to improve the treatment of bipolar disorder. Please contact us if you are interested in participating.