Brain electrodes as depression treatment

No, we're not talking shock therapy. Researchers at the University of Toronto installed deep brain stimulating electrodes in 20 patients with severe depression who weren't helped by other means. Twelve of those individuals saw big improvement and seven experiences a "full remission." The electrodes stimulated a region of the brain called the subcallosal cingulated gyrus. Other centers around the world are running similar studies but zapping different parts of the brain.
“In the meantime we need to know why some of the patients don’t respond at all,” says (researcher Helen) Mayberg. “Are we missing the target, or are there different subtypes of the disease?” Her team is now trying to find out how to identify those who will respond to DBS, and those who won’t. “Brain surgery is not like getting your nails done, so it is important to try to find out who will benefit..."

Neurologists think that the therapy works by activating or damping down particular brain circuits. At the moment, no-one knows which of the targets within these circuits will eventually prove to be the most optimal...

The centres are also investigating the value of DBS in other psychiatric disturbances, such as obsessive compulsive disorder and addiction.
Deep brain stimulation for depression (Nature)