Two of the largest and longest studies so far show a “brain pacemaker” can effectively treat depression and obsessive-compulsive disorder (OCD), researchers said on Friday.

Devices implanted in the chest, with leads that send electrical impulses to parts of the brain, have already been approved to treat movement disorders, such as Parkinson’s disease, essential tremor and dystonia.

Dr. Ali Rezai, head of neurosurgery at the Cleveland Clinic, who led the studies, said the technique known as deep brain stimulation helped the most severely depressed patients improve significantly.

Researchers from Butler Hospital/Brown Medical School, Massachusetts General Hospital and Harvard Medical School were also involved in the depression study.

Seventeen patients, diagnosed as having major depressive disorder, were followed for a year and demonstrated overall improvement in mood as well as social and occupational functioning, he said.

“These were severely depressed patients, the most depressed,” Rezai said in an interview.

Patients included in the study had been depressed for at least five years, and were unresponsive to drug treatment or electric shock therapy, he said.

The brain pacemaker, manufactured by Medtronic Inc, was also effective in treating OCD, said Rezai, who was in Chicago to present the findings to the American Association of Neurological Surgeons meeting next week.

OCD is a psychiatric anxiety disorder marked by recurrent and persistent thoughts and impulses, such as uncontrollable and repeated hand washing.

St. Jude Medical Inc is currently conducting a similar trial using a brain pacemaker to treat depression.

Rezai said the St. Jude trial affects a similar area of the brain and is likely to generate similar findings.

He said there were no serious side effects in using the Medtronic device.

The trial treating OCD included 26 patients who were followed for three years and also showed marked improvement.

Butler Hospital/Brown University, University of Florida and University of Leuven also contributed to the OCD study.

Medtronic has an application before the U.S. Food and Drug Administration for approval to use deep brain stimulation for OCD.

A clinical trial using the treatment for severe depression will be initiated this year.

The FDA in 2005 approved Cyberonics Inc implantable device for treatment-resistant depression. It sends signals to the brain via the vagus nerve in the neck.

By Debra Sherman
CHICAGO (Reuters)