From Scientific American:
Deep depression that fails to respond to any other form of therapy can be moderated or reversed by stimulation of areas deep inside the brain. Now the first placebo-controlled study of this procedure shows that these responses can be maintained in the long term. Neurologist Helen Mayberg at Emory University in Atlanta, Georgia, followed ten patients with major depressive disorder and seven with bipolar disorder, or manic depression, after an electrode device was implanted in the subcallosal cingulate white matter of their brains and the area continuously stimulated. All but one of twelve patients who reached the two-year point in the study had completely shed their depression or had only mild symptoms. For psychiatrists accustomed to seeing severely depressed patients fail to respond—or fail to maintain a response—to antidepressant or cognitive therapy, these results seem near miraculous.