Lana Sanderson felt like she’d run out of options.

After decades of battling severe Depression, nothing - not anti-depressants, not psychotherapy, not even Electroconvulsive therapy - could break the cycle of debilitating sadnesses and manic highs.

So, in November 2000 she had an experimental device implanted in her chest at the University of Washington Medical Center.

A pocket-watch-sized battery is attached to a thin wire that runs up to and wraps around the vagus nerve on the left side of her neck.

Every five minutes, the device sends an electrical charge up the wire, through the nerve to stimulate Sanderson’s brain. The charge lasts for 30 seconds.

Last month, in a controversial move, the U.S. Food and Drug Administration approved the Vagus Nerve Stimulator, or VNS, for patients with treatment-resistant Depression. Only patients who’ve tried at least four other therapies without success should receive the device, according to the FDA.

“These are people with long-standing depression who don’t get better,” said Dr. David Dunner, head of the UW’s Center for Anxiety and Depression, who has conducted studies with VNS. “Either they keep relapsing or they just never improve.”

An estimated 20 percent of patients with major depression fail to respond to multiple therapies.

The VNS device, including surgery, costs between $20,000 and $25,000, according to Cyberonics Inc., the manufacturer. In the wake of the FDA’s approval, insurance companies are now deciding whether to cover VNS for depression.

The vagus nerve connects the brain to many areas of the body, including the heart, lungs, kidneys and larynx. (One of the side effects of the device is hoarseness when it’s on.)

Sanderson, 50, said she noticed a small but significant improvement in her ability to concentrate after receiving the device.

“That, I’m pretty sure, was a result of the VNS treatment,” said Sanderson, who has been diagnosed with bipolar disorder. She abandoned a successful career in pharmaceutical sales in 2000 because of her illness. “It’s hard for me to say how much the VNS has helped versus other components of my treatment, but I feel that VNS is an important component.”

No one knows why VNS, which was approved to treat epilepsy eight years ago, seems to help depressed patients.

In fact, some question whether it actually does.

Dr. Richard Malone, professor of psychiatry at Drexel University in Philadelphia and a member of the FDA advisory panel that considered approval for VNS, said he found the evidence presented by the manufacturer unconvincing. The committee voted 5-2 to approve the device.

“FDA approval allows the company to advertise VNS as an effective treatment,” Malone said. “I’d be concerned that people in the general public would be making an assumption that in my mind isn’t true.”

VNS first arose as a possible treatment for depression after researchers noted an improvement in the mood of epilepsy patients who had the device.

And Dunner said his research indicates that VNS is effective for some people with stubborn depression.

However, the only randomized, controlled study (the gold standard for medical research) looking at VNS did not prove the device effective. That could be because the eight-week trial didn’t last long enough, Dunner said.

A later study compared those who’d been implanted in the first trial with another group of depressed patients. That study found that patients with VNS plus other treatments did better than those without the device.