The study will last 8 to 12 weeks and requires weekly visits. Participants will come to Johns Hopkins for a screening visit during which they will talk with a psychiatrist, answer questions about their mood and symptoms, have their blood drawn and have a brief physical exam. If they meet criteria for the study, any antidepressant medication that they are taking will be tapered and stopped before beginning study medications. Participation in the study includes free study medication, labs, and testing plus reimbursement for transportation. Participants will also be paid and after the study referred back to their treating psychiatrist with treatment recommendations.