Additional Study Information: Are you suffering from chronic depression? We are seeking participants for a depression treatment research study at Columbia University using Transcranial Magnetic Stimulation (TMS). This study develops a more accurate TMS to treat chronic depression. Participation includes clinical assessments and magnetic resonance imaging (MRI). You will receive 27 sessions of TMS treatment over up to 8 weeks. This study will test a novel form of neuronavigated transcranial magnetic stimulation (rTMS) which may achieve better results than conventional rTMS by using a specially processed MRI image to optimize targeting of brain regions thought to contribute to depression. Patients with treatment-resistant depression including those for whom conventional rTMS was not successful may be eligible to participate.