Sending electric current through a thin, wire electrode implanted deep in the brain could do what a cardiac pacemaker does for the heart. Researchers say there is new evidence that a procedure called "deep brain stimulation," or DBS, can treat a variety of obsessive compulsive disorders, or OCD, and some severe forms of depression.
After drug and behavior therapy failed to help his psychiatric patients, Dr. Benjamin Greenberg found DBS made a difference.
"Based on the evidence that we have now, it is about as effective as the lesion procedures have been, which is just over half the patients will be better enough to make it worth doing," says Greenberg, who takes a cautious approach in deciding whether to employ the procedure. He believes it should be used only after all conventional psychiatric treatments have been exhausted.
The surgically implanted electrodes are not a cure. The wires in the brain only improve the functioning of the patients who are otherwise disabled by their compulsions.
"Compulsions are things you do in response, usually, to your obsessions," Greenberg says. "There are things that somebody could see like washing their hands, counting or touching arranging things over and over again or they can things that are hidden checking things mentally or even praying silently."
So far about 70,000 people worldwide have had deep brain stimulation devices implanted. Over the past 10 years, only about 70 patients in the United States have undergone deep brain stimulation to treat their OCD.
The technology has also been used in patients with severe depression who have not responded to other treatments. And it has been deployed experimentally against Parkinson's disease, helping to reduce the characteristic tremors. But medical experts say deep brain stimulation is still a long way from being a standard clinical treatment for mental disorders.
"There has not been a major advance since many years, there are many things now in the pipeline," says Dr Mahlon Delong, professor of Neurology at Emory University, "But in terms of, 'Does it help us in the clinic?' Not yet."
Side effects like bleeding, infections and seizures during the operation are possible and some seizures have also been reported during treatment. The procedure is still highly experimental, and some believe much more research is needed before we know if it's effective.
"A therapy is something that is both safe and effective and this is still investigational," says Dr Joseph Fins of the Weill Cornell Center. "It’s still not vetted to be proven efficacious."
It is also not clear yet exactly where in the brain DBS electrodes should be inserted to target specific psychiatric diseases.
DBS raises an even more fundamental ethical question: whether a psychiatrist can be sure enough of a diagnosis to justify surgically entering a patient's brain.
