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A 'Magnetic' Approach to Treating Depression
July 25, 2012
By Michael Craig Miller, M.D.
Harvard Medical School
There are many psychotherapy and medication options to treat depression. But they don't work for everyone. A relatively new type of treatment, called repetitive transcranial magnetic stimulation (rTMS), could make a big difference in the lives of some people with depression.
In 2008, the U.S. Food and Drug Administration approved the first rTMS device for patients whose depression hasn't been helped by standard treatments, such as medication or psychotherapy.
Before you ask your doctor about it, you should know that rTMS is not widely available. Also, it's usually offered after other treatments have failed. Experts do not recommend rTMS for patients with mild depression or newly diagnosed moderate or severe depression.
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How rTMS Works
Patients sit in what looks like a dentist's chair. A technician places a device with a magnetic coil directly above one side of the patient's scalp. The rTMS device produces a series of strong magnetic pulses similar in strength to those produced during a magnetic resonance imaging (MRI) scan. The pulses are painless and go 2 to 3 centimeters (about an inch) into the brain.
The magnetic pulses create a weak electrical current that can either increase or decrease activity in specific parts of the brain. The doctor can target certain areas of the brain. And vary the strength and frequency of the pulses.
Patients don't need anesthesia for the treatment, so they can drive home afterwards. The magnetic pulses can be noisy. Wearing earplugs or earphones helps. The most common side effects of rTMS treatment are mild to moderate headache or scalp pain on the side closest to the device. Some people experience ringing in the ears from the noise of the treatment. Research shows that people do not develop memory problems after treatment.
The most serious risk of rTMS is seizures, but they are rare. Seizures occur in fewer than 1 patient in 1,000. The risk is probably even lower in healthy people who don't have other seizure risk factors. A careful neurological evaluation can identify any risks.
Typically, initial rTMS treatment involves a 40-minute session, 5 days a week, for 4 to 6 weeks. A patient may need less frequent maintenance treatments afterward. Insurance may not cover the cost of treatment. Costs can vary from $6,000 to $10,000, depending on the clinic and how many sessions a patient needs. Maintenance therapy will add to the bill.
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What the Studies Show
The FDA approved rTMS largely on the basis of an industry-sponsored double-blind randomized controlled study. The participants (301 patients with a current episode of major depression) had not responded to at least 1 and no more than 4 antidepressants. The investigators found that 14% of the people in the rTMS group got relief from their depression by the sixth week, compared with 5% of those who underwent sham treatment.
A randomized controlled study of 190 patients with major depression, funded by the National Institutes of Health, found similar results. Although rTMS worked significantly better than a fake treatment, only a small number of people went into remission. At the end of the third week, 13 of 92 patients (14%) receiving rTMS achieved remission, compared with 5 of 98 (5%) receiving fake treatment.
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Is rTMS Right for You?
Experts believe rTMS is most likely to benefit people who have moderate to severe depression that has been relatively resistant to other treatments. It is impossible to predict who will respond only to rTMS (that is, to rTMS alone and no other treatment). For most patients with depression, psychotherapy and medication are likely to remain the standard treatments.
Since rTMS aims to stimulate the brain relatively directly, it's usually compared to electroconvulsive therapy (ECT). ECT is one of the oldest depression treatments. It has been extensively studied and is widely held to be the most effective available treatment for depression. But ECT remains unacceptable to many patients, so rTMS may be a welcome alternative where it is available. Like ECT, rTMS does involve more effort and time than medication. But it avoids the risks and discomforts of anesthesia.
For a select group of patients with depression, rTMS may strike the best balance of costs and benefits. This interesting treatment is still quite new, however. It is available in relatively few places. And the expense (to the patient or the insurance company) is real. For the people who do respond to it, rTMS could make a big difference in the quality of their lives.
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Michael Craig Miller, M.D., is Senior Editor of Mental Health Publishing at Harvard Health Publications. He is an assistant professor of psychiatry at Harvard Medical School. Dr. Miller is in clinical practice at Beth Israel Deaconess Medical Center, where he has been on staff for more than 25 years.