Researchers are working on a technique that could help ease depression in patients for at least two years.

Deep brain simulation is a surgical procedure that involves implanting a patient with a medical device called a "brain pacemaker". The surgeon attaches the pacemaker to an implantable battery placed beneath the collarbone. The device then sends electrical impulses to specific parts of the brain. The researchers discovered that sending a regular high-frequency electrical stimulation to a patient's brain alleviates the depression the patient feels.

"Depression is a serious and debilitating medical illness," said Dr. Helen S. Mayberg, a professor in the Departments of Psychiatry and Behavioral Sciences and Neurology at Emory University School of medicine and the study's lead investigator.

"When we found that the potential for effective and sustained antidepressant response with DBS for patients with otherwise treatment resistant major depressive disorder was high, the next step was to determine if patients with intractable bipolar depression could also be successfully treated."

Mayberg with colleagues Dr. Paul E. Holtzheimer, lead psychiatrist and now associate professor and director of the Mood Disorders Service, Dartmouth Medical School, and neurosurgeon Robert E. Gross, MD, PhD, associate professor in the Departments of Neurosurgery and Neurology at Emory, studied how DBS can be used to treat depressed patients.

Normally the procedure is used to treat patients suffering from brain disorders such as Parkinson's disease, chronic pain and dystonia but the treatment is equally effective in treating patients suffering from major depressive disorder or bipolar II disorder.

"They say things like they feel lighter, they feel more connected," Mayberg says. "The mental churning or mental pain is gone."

The researchers tested DBS on 17 patients and found that treatment is safe and half of the patients were in remission after two years of treatment. The chosen participants had failed a minimum of four treatments and had been depressed for an average of four years. None of the patients relapsed as long as the device was on.

The doctors chose to send electrical impulses to a region in the brain called Area 25 which plays a role in controlling negative moods.

"If you think of something profoundly negative - if you think of someone dying, or getting sick or a loss - and you take a picture of the brain, the area that changes its activity the most is Area 25," Mayberg said. "That Area 25 just kept reappearing - as we started to see it, it was kind of everywhere."

DBS isn't a treatment that makes patients happy but rather it removes the negative sadness in the patients' brains. The study is published in the Archives of General Psychiatry.