A small electric generator, about the size of a stopwatch, can be surgically attached to rib cage during an operation. The generator is called a Vagus Nerve Stimulator or VNS because wires from the generator travel under the skin up to the neck and wrap around the Vagus nerve, which sends signals to the brain to help regulate moods.

The VNS is programmed by a computer to stimulate the Vagus nerve for 30 seconds every five minutes. The only side effect: a slight change in the patient?s voice because the stimulator is near the vocal chord. The VNS has been used to treat people with epilepsy since 1997.

When scientists noticed it also put patients in a better mood, they decided to try it on severely depressed people. Now the Food and Drug Administration has approved another test of the nerve stimulator at 15 medical centers nationwide.

It could be at least a year before the treatment is widely available, but it does offer hope for the one million people who suffer from untreatable depression.