Magnetic stimulation of the brain can ease drug-resistant depression, study shows

Daily application of magnetic stimulation to the brain for about 37 minutes can ease depression in patients who are not responding to antidepressants, researchers reported Monday. The procedure -- in effect, a mild form of electroconvulsive therapy, or ECT, which has been shown to be very effective against severe depression -- has been approved by the Food and Drug Administration since 2008, but critics have questioned its efficacy because of the lack of suitable blinded trials. That problem has arisen because of the difficulty of performing a sham procedure that recipients might think is an active procedure.

Dr. Mark George at the Medical University of South Carolina in Charleston and his colleagues got around this problem by developing an apparatus that mimics the effects of the magnetic stimulator without actually producing a magnetic field. The device causes a tapping on the skull similar to that produced by the real treatment and causes eyes to twitch in the same manner. Even the physicians who were treating patients were unable to tell if a device was real or simulated.

The researchers enrolled 190 patients who had suffered from depression for at least three months but less than five years and who had not responded to antidepressants. Half received the actual treatment every weekday for three weeks, while the rest received the sham treatment on the same schedule. Ninety percent of those in the sham group completed the study, compared with 86% of those in the treatment group.

The team reported in the Archives of General Psychiatry that 14.1% of those in the treatment group had their depression relieved, compared with 5.1% of those in the control group. When both groups were given the treatment for another three weeks, 30% responded.

"This study should help settle the debate about whether [the technique] works for depression," George said in a statement. Now the team can begin to investigate ways to improve its efficacy. One possible solution, as demonstrated in the study, is to extend the treatment period for longer durations.

The device uses a magnetic coil placed on the head that pulses about 3,000 times during each treatment, stimulating a minute electrical current in the brain. In the trial, the field was focused on the top left front part of the brain. The patient is conscious during the procedure and there appears to be no significant side effects. Patients can drive themselves home afterward.

In ECT, in contrast, electrodes placed against the skin emit an electrical current that passes through the brain, causing convulsions. Patients must be sedated and have to be driven home afterward. Clinical trials are testing the new technique against a variety of other problems, including tinnitus [ringing in the ears] and schizophrenia.

The study was funded by the National Institute of Mental Health.

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