People with otherwise untreatable depression improved in a small clinical trial after receiving electrical stimulation of a part of the brain that scientists believe regulates sadness.
A report this week in the journal Biological Psychiatry said 12 of 20 patients with chronic major depression benefited from the electronic device - including seven whose disease went into remission. The benefits were sustained over the course of the one-year study, researchers said.
"These were patients at the end of the road. They had tried other treatments, and nothing seemed to stick," said University of Toronto neurosurgeon Andres M. Lozano, who led the study.
Major depressive disorder affects about 14 million people in the U.S., and 10 percent to 20 percent of them do not respond to standard medical treatment, according to the study.
The nine men and 11 women selected for the trial had failed to improve on multiple medications, psychotherapy and electroconvulsive therapy, which is considered a last resort. Subjects had been taking an average of four medications when the trial began in 2003 and had suffered from major depression for an average of 6.9 years.
Deep brain stimulation is approved to treat essential tremors and Parkinson's disease. Electrodes, which are permanently implanted in the brain, are powered by batteries and can be turned on and off by an external controller.
In the experiment, the electrodes were placed in the almond-sized subcallosal cingulate gyrus. The theory was that continual electrical stimulation would slow down activity in this area of brain and, in so doing, improve patients' moods.
Six patients showed such marked improvement that they were able to return to work after two to seven years of unemployment because of their illness, according to the study, which was partly funded with a grant from the manufacturer of the device, Advanced Neuromodulation Systems Inc.
Researchers don't know why eight patients failed to respond, Lozano said. A larger study of 150 to 200 patients is under way, he said.
Denise Gellene writes for the Los Angeles Times.