RNA Editing as a Biomarker of Antidepressant Response in Unipolar and Bipolar Depression (EDIT-ANDRE)

This study is investigating whether changes in RNA editing (a biological process in cells) in the blood can predict how well people with depression will respond to antidepressant treatment. It aims to enroll people with major depressive disorder (MDD) or bipolar depression who are starting a new antidepressant. This is a biomarker and treatment response study. **You may be eligible if...** - You are between 18 and 65 years old - You have a current episode of major depression, confirmed by clinical interview (for MDD or bipolar disorder I or II) - Your depression symptoms are at least moderate in severity - You can speak and understand English - You are able to travel to assessment visits - If you have bipolar I disorder, you must be on a mood stabilizer **You may NOT be eligible if...** - You have treatment-resistant depression (failed 2 or more adequate antidepressant trials in the current episode) - You are actively suicidal or have made a medically serious suicide attempt in the past 6 months - You have active psychosis, schizophrenia, or significant mixed mood symptoms - You currently use or have recently used certain medications that could interfere with the study drugs - You have a current substance use disorder (other than nicotine) - You are pregnant, breastfeeding, or not using contraception - You have significant medical conditions such as severe kidney or liver disease, epilepsy, or eating disorders Talk to your doctor to see if this trial is right for you.