Researchers are testing a new treatment for depression in teenagers. The treatment uses a type of brain stimulation called repetitive transcranial magnetic stimulation (rTMS) to target areas of the brain that may be underactive in people with depression. To find the best spot to stimulate, they're using a special machine that looks at how different parts of the brain are connected when the person is not being treated. The study will compare three groups: one group will get the standard treatment, another group will get the new rTMS treatment based on their brain connections, and a third group will get a fake treatment to see if it has any effect.