Repetitive transcranial magnetic stimulation: a novel treatment for depression.

©2005 Elsevier. All rights reserved. Transcranial magnetic stimulation (TMS) is a noninvasive technique used to stimulate the human brain in vivo using very strong, pulsed magnetic fields. Magnets exist in the natural world in a very weak form, and technologic advances in the last 2 decades have made it possible for magnetic stimulators to produce sufficient electric current in the brain to cause neuronal depolarization. Repetitive TMS (rTMS) is rapidly developing as a powerful, non-invasive tool for studying the human brain, and also as a novel treatment for neuropsychiatric disorders. The magnetic field strength used clinically (about 2 T) is about 40,000 times the earth’s magnetic field. Clinically, rTMS has been applied to treat mood and anxiety disorders, schizophrenia, movement disorders, and epilepsy. rTMS was first reported to have antidepressant efficacy in 6 medication-resistant patients with depression. Subsequently, there were many open and controlled studies of this novel therapy. In a systematic review of data from 14 randomized controlled trials in patients with depression who received or did not receive rTMS, an effect in favor of rTMS was evident: after 2 weeks’ treatment, the standardized mean difference in Hamilton Rating Scale for Depression (HAM-D) score between the rTMS and control group was –0.35 (95% confidence interval [CI] –0.66, –0.04); however, the standardized mean difference at a 2-week follow-up visit was not statistically significant (–0.33; 95% CI, –0.84, 0.17). The authors suggested that studies were of low quality and provided insufficient evidence to support the use of rTMS in the treatment of depression. Further, in a randomized controlled comparison of electroconvulsive therapy (ECT) with rTMS in severe and resistant, nonpsychotic, major depression, the Repetitive Transcranial Magnetic Stimulation: A Novel Treatment for Depression