Precision Medicine in the Depression Treatment

This study is developing a precision medicine approach to depression treatment — using brain scans, blood tests, and detailed assessments — to better match patients with the most effective therapy for their individual profile. **You may be eligible if...** - You are between 18 and 65 years old - You have been diagnosed with a primary depressive episode (not caused by another condition) - You have been referred for treatment for a single episode of depression **You may NOT be eligible if...** - You have psychosis or psychotic symptoms - You have had a severe head injury - You have a brain tumor or a disease that causes changes to brain structure - You do not have enough Danish language skills to complete questionnaires and tests - For those in certain study groups: you are pregnant or breastfeeding, have contraindications to MRI, have had significant radiation exposure recently, or are taking psychiatric medications Talk to your doctor to see if this trial is right for you.