Transcranial magnetic stimulation for the treatment of depression

Abstract

Repeated daily left prefrontal transcranial magnetic stimulation (TMS) was first proposed as a potential treatment for depression in 1993. Multiple studies from researchers around the world since then have repeatedly demonstrated that TMS has antidepressant effects greater than sham treatment, and that these effects are clinically meaningful. A large industry-sponsored trial, published in 2007, resulted in US FDA approval in October 2008. Most recently, a large NIH-sponsored trial, with a more rigorous sham technique, found that a course of treatment (3–5 weeks) was statistically and clinically significant in reducing depression. However, consistently showing statistically and clinically significant antidepressant effects, and gaining regulatory approval, is merely the beginning for this new treatment. As with any new treatment involving a radically different approach, there are many unanswered questions about TMS, and the field is still rapidly evolving. These unanswered questions include the appropriate scalp location, understanding the mechanisms of action, refining the ‘dose’ (frequency, train, number of stimuli/day and pattern of delivery), understanding whether and how TMS can be combined with medications or talking/exposure therapy, or both, and how to deliver maintenance TMS. This article summarizes the available clinical information, and discusses key areas where more research is needed. TMS reflects a paradigm shift in treating depression. It is a safe, relatively noninvasive, focal brain stimulation treatment that does not involve seizures or implanted wires, and does not have drug–drug interactions or systemic side effects.

Keywords::

• depression
• TMS
• transcranial magnetic stimulation
• treatment-resistant

Financial & competing interests disclosure

Mark George reports no equity or other direct financial investment in any device or pharmaceutical firm. Within the past 3 years he has: served as a paid consultant to Glaxo-Smith-Kline, Jazz Pharmaceuticals, Cyberonics and Neuropace; received research grants from Glaxo-Smith-Kline, Jazz Pharmaceuticals and Brainsway; served as an unpaid consultant to Brainsonix, Brainsway, Neuronetics and NeoStim; and been the editor-in-chief of a journal published by Elsevier, entitled Brain Stimulation. The Medical University of South Carolina holds patents in the area of combining TMS with functional brain imaging. The total compensation from any company in a single year has been less than US$10,000. The total combined compensation from all consulting activities is less than 10% of his university salary. The author has no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.