Optimized Predictive Treatment In Medications for Unipolar Major Depression (OPTIMUM-D)

This study tests whether combining clinical information with brain imaging and biological markers can predict which antidepressant medication will work best for a specific patient. The goal is to reduce trial-and-error in depression treatment. **You may be eligible if...** - You are between 18 and 65 years old - You have been diagnosed with a major depressive episode (MDD) confirmed by a structured interview - You are not currently taking any psychiatric medications (or have been off them for the required time period) - Your depression symptoms are significant (MADRS score of 24 or higher) - You are fluent in English and can complete questionnaires **You may NOT be eligible if...** - You are currently taking antidepressants or other psychiatric medications (except stable hypnotics or ADHD stimulants) - You have bipolar disorder, psychosis, or active substance use disorder - You have significant medical conditions that could affect brain or mood function - You are pregnant or breastfeeding - You have a history of non-response to multiple antidepressants Talk to your doctor to see if this trial is right for you.