Transcranial Magnetic Stimulation (TMS) is a therapy, covered by insurance, that uses magnetic fields to stimulate activity in a depressed brain. These magnetic fields will stimulate nerve cells in your brain and are applied through non-invasive methods. The stimulation improves symptoms of depression. TMS is generally used when other treatments for depression have failed. This method of treatment delivers repetitive magnetic pulses; this has earned it the name of repetitive TMS or TMS when identifying the method.