DEAR DOCTOR K:
I have major depression that hasn’t responded to medication. My doctor said I might be a candidate for rTMS. What is this? How does it work?
For most of the past century, the main treatments for major depression have been various forms of “talk therapy” and anti-depressant medicines. The primary exception was electroconvulsive therapy, or ECT (also known as shock therapy). While effective, it is used only in the most severe cases.
In the past 10 to 20 years, other, gentler forms of therapy that also use electrical technology have been developed for depression and other brain conditions. One is called deep brain stimulation. Another is vagus nerve stimulation.
Still another is rTMS, or repetitive transcranial magnetic stimulation. It uses magnetic fields to stimulate parts of the brain. One machine for performing rTMS was approved in 2008 by the U.S. Food and Drug Administration for treatment of depression that has not responded to talk therapy or anti-depressant medicines. So, rTMS may be helpful for someone like you.
What’s it like to receive the rTMS treatment? You sit in a chair while a device containing a magnetic coil is placed over your scalp. It focuses on a part of your brain that plays a role in mood regulation. The device produces a series of strong magnetic pulses that penetrate about an inch into your brain.
It’s not clear how rTMS eases depression. The magnetic pulses may create a weak electrical current that changes nerve cell activity in certain regions of the brain.
The procedure isn’t invasive. It doesn’t cause loss of memory or concentration, and doesn’t require anesthesia. (In contrast, ECT requires general anesthesia and can produce some temporary problems with memory.) A person undergoing rTMS remains awake, and there isn’t any recovery time, so you can go about your usual activities afterward.
The entire procedure takes 30 to 45 minutes. The therapy usually is done once a day, five days a week, for four to six weeks. Less frequent maintenance therapy may also be needed.
There are few side effects. The most common ones — headaches, scalp discomfort or facial twitching — are mild.
This is still a relatively new therapy. It was approved on the basis of a large and well-designed (though industry-sponsored) study, and appears to be moderately effective. However, it is not as effective as ECT.
Doctors are still learning how best to use rTMS for depression. Are there some patients who are likely to benefit and others who are not? Would changing the strength of the magnetic field, or placing the coils in a different position, improve the results? Hopefully, as with many new types of therapy, the effectiveness of rTMS will improve with time.