The oft-quoted success rate for electroconvulsive therapy—that it brings remission to 80 percent of people who try it—was arrived at under the rigorous setting of a clinical trial. A 2004 study of ECT success rates in the community hospital setting put the number between 30 percent and 47 percent. The discrepancy probably reflects variation in doctors' techniques, additional complicating illnesses, and the fact that some patients stop ECT early because of side effects, says Lisanby.
In the face of ECT's shortcomings, newer brain-stimulation treatments are being explored. But none are widely available, and how well each works and for whom is not yet known. Transcranial magnetic stimulation, which has been cleared by the Food and Drug Administration for depression, targets neurons in areas of the brain involved in mood by placing a magnetic coil on the head. Unlike ECT, it does not result in a seizure or require anesthesia, nor does it cause memory loss. But it is hardly available in every community and may not work well for patients with more severe cases. In vagus nerve stimulation, a device surgically implanted in the chest stimulates the brain by shooting electrical pulses into the vagus nerve in the neck. "To many in the field, the jury is still out" on its effectiveness, says Rudorfer. Deep brain stimulation, approved for movement disorders, including Parkinson's disease, is available for depression only in research trials. It involves surgery to place electrodes into the brain and a small battery pack in the chest. The good news, says Rudorfer, is that most people will respond to a mainstream treatment—as long as they persevere.