Accelerated Intermittent Theta Burst in Treatment-Naive Adolescents

This trial is testing whether an intensive brain stimulation treatment called accelerated intermittent theta burst stimulation (aiTBS) — a type of non-invasive magnetic brain stimulation — can help teenagers and young adults experiencing their first episode of major depression who have never been on antidepressants. **You may be eligible if...** - You are between 14 and 19 years old - You have been diagnosed with Major Depressive Disorder (MDD) and are currently in a depressive episode - This is your first depressive episode (no prior episodes) - You have a depression severity score of at least 20 on a standard rating scale (HAMD-17) - You have never had a full course of antidepressant medication or psychotherapy - You have not previously received TMS (transcranial magnetic stimulation) - You have access to ongoing psychiatric care - You are able to read and understand English **You may NOT be eligible if...** - You are pregnant - You are actively suicidal or at high risk of suicide - You have a significant anxiety disorder, dysthymia, bipolar disorder, or psychosis - You have severe insomnia (sleeping less than 5 hours per night) - You have autism, intellectual disability, or OCD - You have a current moderate or severe substance use disorder - You are currently using ketamine or another fast-acting antidepressant Talk to your doctor to see if this trial is right for you.