(NaturalNews) A therapy known as repetitive transcranial magnetic stimulation (rTMS), which involves inducing electromagnetic fields in the brain, may ease the symptoms of depression in hard-to-treat patients better than antidepressant drugs, researchers have found.
"This study should help settle the debate about whether rTMS works for depression," said lead researcher Mark George of the Medical University of South Carolina. "We can now follow up clues suggesting ways to improve its effectiveness, and hopefully further develop a potential new class of stimulation treatments for other brain disorders."
RTMS therapy uses highly focused magnetic pulses similar in strength to those produced by an MRI to induce an electric current in the Dorsilateral Prefrontal Cortex in the front left portion of the brain. Over the course of a single, 37-minute session, the brain is exposed to a total of 3,000 such pulses.
RTMS is the only FDA-approved biological depression treatment besides antidepressant drugs and electroconvulsive therapy (ECT, also known as electroshock therapy). It functions under basically the same mechanism as ECT, but without inducing seizures.
Prior studies have demonstrated the effectiveness of rTMS, leading the FDA to approve it as a treatment for depression in 2008. Since then, more than 20,000 procedures have been performed. Yet because scientists had never been able to develop a way to test the device against a placebo -- study participants were consistently able to tell whether they were receiving the real treatment or not -- critics have questioned the validity of the therapy.
For the new study, published in the Archives of General Psychiatry, researchers developed a device that causes the same eye-twitching and skull-tapping sensation induced by an rTMS machine, but without making use of electromagnetic fields. This sham treatment device and its physical effects appeared so similar to that of the real device that even the researchers could not tell them apart.
The researchers tested either true rTMS or the sham device on 190 patients who had suffered from serious depression for between three months and five years. All study participants had previously been treated with at least one antidepressant drug but had failed to respond.
After at least three weeks of treatment, 14 percent of the patients in the rTMS group experienced remission of symptoms, compared with only 5 percent in the sham treatment group.
"The effect sizes we report with rTMS are about on par with what you see with antidepressant medications," said researcher Sarah Lisanby of Columbia University and the New York State Psychiatric Institute. "The difference is that to get into our study, people had to have failed to have responded to a medication. And studies show that with previous failure to respond to an antidepressant, the rate of success for a second antidepressant is lower."
The researchers found that rTMS was more effective in patients who had previously taken only one antidepressant than in patients who had taken more than one.
"It is looking as if rTMS would be more effective earlier in the treatment course rather than later," said Matthew Rudorfer, of the National Institute of Mental Health, which funded the study.
Although the study was conducted without any industry support, all the researchers reported financial relationships with companies involved in rTMS. In addition, Columbia University holds an rTMS patent in Lisanby's name.
Participants in both the real- and sham-treatment groups suffered some side effects such as headaches and nausea. These effects were more common in participants that underwent true rTMS. Unlike antidepressants, however, rTMS does not circulate through the body and should have no systemic side effects such as dry mouth, sexual dysfunction, upset stomach or weight gain.
In contrast with ECT, no sedation is required for rTMS and patients can drive themselves to and from their appointments.