A small device, implanted in the chest, can potentially treat depression and obsessive-compulsive disorder in most patients. The device, produced by Medtronic, prevents recurring feelings of depression or obsession by shocking the brain consistently.

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.

The technique, called Deep Brain Stimulation, stimulates the neural circuits which control mood and anxiety.