Doctors long have struggled over what to do with severely depressed patients who don't respond to treatment. Give them more medications that haven't worked so far? Recommend more talk therapy or another round of shock treatment?
Here's a new idea: open up a depressed head, find the brain parts that aren't working, and fix them with electricity. It's not all that far-fetched. Earlier this month, the Food and Drug Administration gave a medical device manufacturer the green light to recruit patients for a large-scale clinical trial of an electrode implanted deep inside the brain to alleviate severe depression. As invasive and Frankenstein-ish as it may seem, deep brain stimulation, as the method is called, may offer real hope for the 20 percent of depressed Americans whom Prozac can't help.
Anti-depressant drugs carpet-bomb the entire body. Electroconvulsive therapy jolts the whole brain. Deep brain stimulation aims to pinpoint the malady. Neurosurgeons drill through a patient's skull, place the DBS electrode's eight contact points directly on the trouble spots and connect them to an electrical current from a pacemaker embedded in the chest. This allows doctors to rev up sluggish areas or calm overactive regions.
DBS has been used for a decade to control symptoms of Parkinson's disease. Using it to treat depression poses a different challenge. While neurologists may have found the region of the brain that controls tremors, they haven't yet confirmed where those magic buttons are for mental illness. How do you isolate something as all-consuming as depression—the grief, irritability, self-defeating thoughts, and irregular interest in food, sex, and sleep—in a few millimeters of gray tissue?
Despite the obstacles, the results of small studies testing DBS on depressed patients are promising. For example, researchers are honing in on the region known as the subgenual cingulated, which scans show is overactive in the brains of depressed patients and subsides when they undergo ECT or take antidepressants. (The same area lights up when nondepressed people experience extreme sadness.) Critics caution that highlighted areas on a scan don't necessarily correspond to the loci of depression, yet early research shows that depressed patients feel better when the area is continually stimulated. One such study of brain implants, by Emory psychiatric neurologist Helen Mayberg, found striking and sustained improvement in four of six patients. They reported feeling suddenly calm, aware, and interested in social activities. Some talked more spontaneously, louder, and with more emotion. Others said the colors in the room became brighter and details were more vivid.
Another research team is targeting a different but nearby part of the brain—the network of nodes in the frontal lobe and base of the thalamus and basal ganglia, where emotion, attention, and anxiety are believed to converge. In a recent study for another device manufacturer, researchers from Brown University and Cleveland Clinic found that five of 10 patients treated with DBS between 2003 and 2006 showed a 50 percent reduction in the severity of their depression one year later. Patients said they had less anxiety, more energy, and felt more connected with themselves and people around them. One said simply, "The fog has lifted." The researchers are waiting for approval to start enrolling patients in a bigger trial later this year.