Minds and Magnets

By Michael Craig Miller, M.D.; Miller is editor in chief of the Harvard Mental Health Letter and a member of the faculty of Harvard Medical School. For more information go to health.harvard.edu/NEWSWEEK.

Anne and mark (not their real names) could never have guessed that their lives would be saved by magnetism. Both had suffered at least a year of disabling depression. Numerous psychiatric treatments failed to provide longed-for relief. Life was miserable until they began receiving an experimental treatment with a clumsy name: repetitive transcranial magnetic stimulation, or repetitive TMS.

This magnetism has nothing to do with magnets applied to the skin or with animal magnetism, the charlatanry invented by Franz Mesmer in the 19th century, although skeptics have worried that people cured by repetitive TMS have merely been mesmerized. Repetitive TMS uses real magnetic fields to induce changes in brain function, and there's some evidence it may make nerve-cell connections more efficient. It may modify how regions of the brain work together to regulate mood. It's a cousin of "shock therapy," or electroconvulsive therapy (ECT). Unlike ECT, however, it does not require anesthesia. It's localized, so side effects have been mild; some patients experience headache or scalp discomfort.

TMS was developed more than 20 years ago by neurologists studying brain function, rather than treatment. The technique exploits the relationship between electric currents and magnetic fields. When an electric current in a wire changes, it creates a magnetic field. That magnetic field can create an electrical current in another wire. In repetitive TMS, a coil that is shaped, for example, like a doughnut or figure-8 is held over the scalp. By rapidly changing the charge in the coil, the magnetic field induces an electric current in the brain that is strong enough to activate nerve cells below the scalp. The coil may look large, but the area affected can be as small as a pea. In contrast, ECT causes a generalized or whole-brain seizure, with electrical changes throughout the brain.

This modicum of intrusiveness appealed to Mark. One day when he was 15, he told his parents he was going to the library, but he went to a nearby bridge instead, planning to jump. Police rescued him. Two years of repeated hospitalization, medication and psychotherapy did not help; so he began ECT. It worked, but he required monthly maintenance treatments that were embarrassing and disruptive because he could not function well in the days around the periodic treatments.

Mark's mother found out about repetitive TMS from a news report almost 10 years ago when he was 17. She tracked down Dr. Alvaro Pascual-Leone of the Center for Noninvasive Brain Stimulation at Beth Israel Deaconess Medical Center in Boston. Within two weeks of treatment he received as part of a study, Mark developed a more positive outlook. He has needed maintenance treatment every four months or so, but it has not interfered with intellectual functioning the way ECT did. He finished high school, and earned two college degrees in education. Now he's a teaching assistant, optimistic that he will realize his goal of being a teacher.