Major depression is a type of depression that can interfere with the ability to work, study, sleep, eat, and enjoy once pleasurable activities. Because people often develop resistances to medications used to treat depression, new treatments are needed. Decreased electrical activity in the prefrontal region of the brain has been linked to some symptoms of depression. Repetitive transcranial magnetic stimulation (rTMS) can be used to influence the brain's electrical activity. This procedure entails attaching electrodes to the head and using a device to pass magnetic energy through coils and into the brain. rTMS has been shown to have antidepressant effects in depressed individuals. However, optimal levels of intensity and treatment duration have yet to be determined. This study will assess the safety and effectiveness of rTMS on the prefrontal region of the brain in depressed adults with moderate treatment resistance.