People suffering from major depression that does not yield to antidepressant medication may receive lasting relief from a very different form of therapy in which a pulsed magnetic field stimulates a portion of the patient's brain, a study shows.
In a study of the therapy, transcranial magnetic stimulation or TMS, nearly half of 301 treatment-resistant participants showed complete or partial improvement in their symptoms, says Philip G. Janicak, M.D., a professor of psychiatry at Rush University Medical Center in Chicago and lead author of a paper published in October in the journal Brain Stimulation.
Better still, only 13 percent of those who responded to the therapy relapsed into depression after six months, he says.
The procedure is performed on an outpatient basis, and is well-tolerated by most people, although some experience discomfort. "A lot of people describe it as the feeling of a woodpecker tapping at their foreheads," Janicak says. The magnetic field is much less powerful than the electrical current used in earlier electric shock treatment.
In the study's first "blinded" phase—conducted at 20 sites in the United States, Canada and Australia—people received either real or sham treatments with a Neuronetics stimulator, which beams a rapid series of magnetic pulses to a left-brain region that is less active in people who are depressed.
In the next phase, everyone received real magnetic treatment while also starting on a maintenance dose of an antidepressant drug to help prevent relapse. Finally, everyone was tapered off of the magnetic treatment, while remaining on an antidepressant, and followed for six months.
"If they started to show the earliest signs of a recurrence of their depression we reintroduced TMS, this time to augment their antidepressant," Janicak says. "We were able to prevent relapse in about 85 percent of those that showed the earliest signs [of depression]."
"It certainly is encouraging and gives us some direction as to how we might want to conduct larger, more definitive studies," Janicak says.
The magnetic pulse treatment is safe and appears to increase blood flow and metabolism in the targeted brain structure, while indirectly affecting other regions, Janicak says. Federal regulators approved the Neuronetics TMS device for depression treatment in October 2008.
David Avery, M.D., a University of Washington psychiatry professor who contributed to the study, points out that its subjects were "at much greater risk for relapse than the person in the average antidepressant trial." In light of that, he says, the 10 percent relapse rate is low compared to the usual relapse rates seen in those with severe depression.
Coauthor John P. O'Reardon, M.D., associate professor of psychiatry at the University of Pennsylvania, says the study also showed that "if you opt to go on medication and keep TMS as a backup, it should work very well."
Meanwhile, because long-term maintenance of patients with TMS treatment hasn't been studied in depth, "this breaks new ground," he says.
Michael Haederle is a freelance writer whose work has appeared in People, the New York Times and the Los Angeles Times.