Transcranial Magnetic Stimulation device for treatment-resistant Major Depression just approved by the FDA

Mark Dombeck, Ph.D. was Director of Mental Help Net from 1999 to 2011. Dr. Dombeck received his Ph.D. in Clinical Psychology in 1995 ...Read More

According to a press release dated October 8, 2008, the FDA has cleared a Pennsylvania company, Neuronetics, Inc. to sell its NeuroStar Transcranial Magnetic Stimulation system for use as a treatment for treatment-resistant Major Depression. This is, to my knowledge, the first time that this technology has been available for use by regular psychiatrists for use in treating regular depressed patients. This is potentially a great thing for patients suffering with severe depressions that aren’t helped by conventional treatments, but I’ll need a few paragraphs to explain why.

Major Depression is an uneven disease which can have various courses for different people. Some people develop a single episode during their lives and do not repeat the experience, while others develop a pattern of reoccurring depressions that persist more or less chronically. Some people have very light depressions, while other people have depressions that are quite severe, featuring psychotic symptoms including hallucinations as well as an all but complete inability to function physically and, of course, a pervasive feeling of worthlessness, hopelessness and a desire to suicide. A portion of the people who develop the more severe forms of Major Depression can be helped with conventional antidepressant and antipsychotic medication treatments as well as by (or in addition to) various specialized forms of psychotherapy such as cognitive therapy for depression. There is also a portion of the population of severely depressed people who don’t respond well to medication or psychotherapy. When conventional therapies fail, the treatment of last resort has typically been electro-convulsive therapy or ECT.

Simply put, ECT involves the passage of an electric current through the brain. No surgery is required. Instead, current is passed through the brain using external electrodes and contact jelly. The current is precise and honed so as to have the maximum desired therapeutic effect with a minimum of side effects. Patients are sedated so that the jolt from the current, which causes a controlled brain seizure, does not cause the person’s muscles to contract uncontrollably, possibly resulting in damage to the body. Patients emerge from each session (multiple sessions are required to produce the antidepressant effect) with little or no memory of having experienced the procedure, and feeling cognitively fuzzy, as ECT is associated with short term memory deficits (which are generally considered to be temporary in nature). Importantly, though, a course of ECT frequently will cause a treatment-resistant depressed person to “snap out of it” fairly well, and become again able to function in life, albeit with some memory problems for a while. Since most of the people who qualify for ECT in the first place have, as their alternative mental state a profound desire to die, most find their post-ECT condition an acceptable trade-off.

Though ECT works, it is as stated above, not without side effects. It is also feared. Ask a random person about ECT and it is likely, if they’ve heard of it at all, that they will tell you about “One Flew Over The Cuckoo’s Nest“, the old movie featuring Jack Nicholson; they imagine a drooling man, recently lobotomized by a corrupt psychiatric establishment. This is not the reality of modern ECT, but it remains the dominant perception.

Because of ECT’s side effects, and its reputation, researchers have for a number of years now sought to find more focused ways to deliver electrical stimulation to the brain with a better side effect profile, and with fewer negative stereotypes. Transcranial Magnetic Stimulation (TMS) is one of these alternative delivery methods, along with Vagus Nerve Stimulation, and Deep Brain Stimulation. The latter techniques deliver an electrical current directly, through the surgical placement of an electrode inside the body (either in the brain itself, or in the vagus nerve) connected to an implanted pacemaker like device to provide constant stimulation. Deep Brain Stimulation techniques are today entirely experimental, although they show great promise. Vagus Nerve stimulation has been FDA approved for Major Depression (meaning that doctors are free to offer it to patients) since 2005, but they require surgery, and the implantation of a pacemaker-like device inside the body. The new Transcranial Magnetic Stimulation technique just approved requires no surgery at all, no implanted devices, and no medications (of which I’m presently aware). It also does not require people to have electric current pass through their brain, which makes it a much less frightening technology for people to contemplate submitting themselves to. What it does involve is the passage of a strong magnetic current through the brain, in much the same way that occurs when an MRI brain scan is taken. MRI technology has been around a long time now and is not perceived as threatening or dangerous. Also very importantly, there are no memory side effects associated with exposure to such magnetic waves. Provided that this new TMS technology packs the antidepressive punch of ECT and continues to show fewer side effects than ECT, I think we will, in fairly short order, start to see it become the dominant treatment for treatment resistant depression.

ECT functions by creating what can be though of as a controlled seizure in the brain. The neurons in the brain are literally arranged into electrical circuits (though circuits made of neurotransmitters and electrically charged calcium ions rather than copper wire), and these circuits get triggered to fire when a current is introduced to them (in much the same way that a recently dead frog’s leg can be made to jerk when a battery is attached to it). TMS functions to activate brain electrical circuitry in an indirect manner, which I think (but am not entirely sure) must function through the deep physical relationship between electricity and magnetism (a pulsing magnetic field can create an electrical current – think of the alternator in your car or the generator at the power company – and, inversely, an electrical current can create a magnetic field – think of electromagnets). Neuronetics, Inc.’s NeuroStar website suggests that the NeuroStar TMS device delivers focused magnetic waves, directed towards the frontal brain; an area known to be involved in mood regulation, which is deeply interconnected with the limbic system portion of the brain where moods originate.

What are the side effects of this device? And just how well does it work? The device is too new to really know the answer to these questions in detail. However, we can talk about the preliminary studies that have convinced the FDA to grant its approval (we hope in an unbiased manner). Like ECT, treatment for depression with the TMS system requires multiple sessions of stimulation. The manufacturer suggests that each TMS session should last about 30 minutes. Unlike ECT, however, no sedation is required during these sessions (the patient remains alert and active throughout, and there is no loss of consciousness), and also there are no reported memory or cognitive symptoms at the conclusion of the treatment process. That is huge!

Keeping in mind that the manufacturer is motivated to present themselves in the best possible light, the data summarized by the manufacturer suggest that there was a robust antidepressant effect in samples of treatment resistant, non-psychotic depressed people. At the conclusion of a six week course of TMS therapy, over 50% of the subjects showed significantly reduced depressive symptoms, and some 30% appear to have remitted (as measured by Hamilton scores (a standardized depression interview) below 11). I don’t know how that stacks up against ECT results, but provided these are non-distorted figures, it isn’t shabby even if ECT retains a superior position in terms of depression remission potential.

This machine is just being released now, and you can expect that it will cost an arm and a leg, and that only a few clinics will have them available for some time. Since the treatment is no longer considered experimental, I would hope that insurance companies will pay for it, but that remains to be seen too. I suspect that this treatment will be hard to obtain for a while. Still, this is exciting and hopeful news. I would like to think that this represents a major leap forward in the treatment of Major Depression.

For more information on the NeuroStar Transcranial Magnetic Stimulation device, you can visit the Neuronetics website section devoted to this product, at www.neurostartms.com. There is also a Wikipedia article on the subject. You might also want to search around the web for less biased sources of information (because the manufacturer is never going to present their product in a bad light, but some bad light may be yet to be revealed).

Update: 2008-11-11: I have received communication from a Ms. Stephanie Ballard of MindCareCentres in Vancouver, Canada, who has informed me that while the NeuroStar device is currently the only FDA approved rTMS device available in the United States, that other rTMS devices have been available in other countries for some time. The MindCareCentres use a device called the Medtronic MagPro which was apparently approved for use in Canda in 2000. More information about MindCareCentres is available at their website. More information on the MagPro is avaiable at the Medtronic website.

Update: 2009-06-16: The company has updated their website to include a Find a Provider section, which will allow people to search for current and future providers who offer treatment with NeuroStar TMS Therapy. That resource is located at http://www.neuronetics.com/Contact-Find-Provider.aspx

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