This nytimes article points out that:
A top federal medical official overruled the unanimous opinion of his scientific staff when he decided last year to approve a pacemaker-like device to treat persistent depression, a Senate committee reported Thursday.
The device, the surgically implanted vagus nerve stimulator, had not proved effective against depression in its only clinical trial for treatment of that illness. As a result, scientists at the Food and Drug Administration repeatedly and unanimously recommended rejecting the application of its maker, Cyberonics Inc., to sell it as such a treatment, said the report, written by the staff of the Senate Finance Committee.
But Dr. Daniel G. Schultz, director of the Center for Devices and Radiological Health at the agency, kept moving the application along and eventually decided to approve it, the report said.
That approval did follow the backing of a divided F.D.A. advisory committee.
When some epilepsy patients reported that their moods had changed after receiving the devices, Cyberonics, based in Houston, implanted them in 235 depressed patients and turned the machines on in half of them. After three months, the two groups were equally depressed. The trial had failed.
Cyberonics then turned the devices on in all 235 patients and determined that 30 percent showed significant improvement after six months or more. Without a control group, however, it was impossible to determine if the device had caused the improvement.