Narrator: This is Science Today. A device used to treat epilepsy has been found to benefit some patients with severe depression. In a recent study, doctors used a pacemaker-like device called the vagus nerve stimulator to send pulses of electricity to the brain. It lifted the mood of about 40 percent of severely depressed patients. Dr. Evelyn Tecoma, of the University of California, San Diego was not part of this study, but she's been working with this device to treat epilepsy since 1993.

Tecoma: There are two components to the vagus nerve stimulator. There's a pulse generator, which is implanted in the chest wall. It's about the size of a small pocket watch and it is implanted in the chest wall much like a cardiac pacemaker.

Narrator: From there, several wires under the skin travel up to the neck and are attached to the vagus nerve, which is near the carotid artery.

Tecoma: It's a device that can be programmed to deliver the stimulus at intervals. So, it's not on all the time - it comes on periodically.

Narrator: As a possible treatment for depression, the results were very encouraging but more study is needed. For Science Today, I'm Larissa Branin.