Brain Magnetic Stimulation Effective for Severe Depression, Approved by FDA
Medical University of South Carolina physician Dr. Mark S. George has answered the question of whether a technique involving brain stimulation will work for resistant, severe depression. "The answer is 'yes’,” he says.
Transcranial magnetic stimulation (TMS) is a technique that uses magnetic coils to deliver a daily dose of an electrical current that passes through the skill to reach a specific part of the brain called the left prefrontal cortex that plays a role in emotion and mood regulation. It has been approved by the US Food and Drug Administration for depression resistant to other treatments.
Using electric current to resolve depression was first performed in the 1940’s and 1950’s. One more familiar technique, called electroconvulsive or electroshock therapy can induce seizures and may cause memory loss and brain damage. TMS is a less invasive form of ECT.
Issues with proving the technique’s effectiveness included the ability to compare TMS to a fake or placebo without either the participant or the researcher knowing which was which, called a “double blind study”. Dr. George solved the problem by developing a “dummy device” that clicks and causes the eye muscles to twitch, just like the real TMS device.
Dr. George and colleagues randomly assigned 190 patients to two groups, one receiving 37.5 minutes of TMS while the other spent the same amount of time on the dummy. The patients had been depressed at least three months, but not longer than five years, and had taken multiple medications that did not resolve the depression.
The treatments occurred once a day for three weeks. After the study period, 14% of the real TMS group recovered from their depression compared to 5% of the group receiving the placebo, making them four times as likely to recover.
In the second phase of the study, all patients were given the real TMS treatment, and 30% recovered from depression. Side effects reported by the study participants included headache, discomfort at the TMS site, and eye twitching.
Patients who had their depression resolve were then given the antidepressant Effexor (venlafaxine) and a small dose of lithium, a combination shown to help people stay well after treatment. Most participants remained depression-free for several months after the study.
Further studies of TMS will include learning how long a treatment is needed to be optimally effective. "It's very muddy now exactly how long we need to treat patients," George said. "It looks as if from this trial you at least need to try three weeks and maybe even six weeks before you would give up." Dr. George would also like to try intermittent TMS treatments in an effort to avoid giving the medications once symptoms resolved. "I'm optimistic that it's pointing us in a path of understanding how to interact with the brain in a non-invasive way to get people well."
George M, et al "Daily left prefrontal transcranial magnetic stimulation therapy for major depressive disorder: a sham-controlled randomized trial" Arch Gen Psychiatry 2010; 67: 507-16.