But The Early Show's Health Contributor Dr. Bernadine Healy reports an experimental device that stimulates the nervous system with electricity may bring relief.
Forty-seven-year-old Tucker Davis of Colleyville, Texas, has a new outlook after a lifetime struggle with depression.
"That sense of helplessness and hopelessness was going away. I felt a reason to be alive again," Davis says.
The secret to his change of heart may lie in a revolutionary pacemaker-style implant. It sends electrical impulses to his central nervous system and brain.
Since he received the device, his depression symptoms have all but disappeared.
"I noticed the concentration coming back, the memory coming [back], the irritability went away," Davis says. "I was sleeping better. I was gaining weight; all these things came in little increments."
The implant provides periodic mild electrical stimulation to the vagus nerve in the neck. The nerve conducts the electricity to areas in the brain associated with the symptoms of depression. It's not clear exactly why or how the treatment works.
"It's a very very subtle and gradual effect," says Dr. A. John Rush of the University of Texas Southwestern Medical Center, adding that not everybody responds and the benefits are not immediate.
"When people respond to this, it isn't turn it on, and you get better. Some individuals maybe in a few weeks will show a response; some may take six or even eight and now some people longer," explains Dr. Rush.
While there is no pain during stimulation, the device causes some patients to experience a tightening of the vocal chords.
But for Davis the side effects are a small price to pay; he is thankful for a treatment that has finally brought him up from the depths.
"Life has changed 100 percent for the better. I feel very optimistic about the future. I'm happy, and that's not a word I used very often," he adds with a grin.
The study of this treatment is still in very early stages. It needs to be backed up with further research and is likely to take a few years before a treatment will be available to patients.
The vagus nerve is believed to be related to other disorders. The stimulator has already been tested and approved by the Food and Drug Administration for epilepsy patients. It was during these epilepsy studies that researchers first noticed the depression-relieving results.
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