Zapping depression

In the late 1700s, Italian anatomist Luigi Galvani made a dead frog's muscles twitch when struck by a spark, a discovery that paved the way for the modern understanding of electricity's role in living things. It is the basis for countless medical technologies like the pacemaker.

But electricity does not travel easily through the skull to the brain, the organ responsible for every purposeful twitch and altered mood. So when a group of British scientists in 1985 used magnetic pulses from outside the head to induce an electrical field inside the brain - and got a subject's hands to move - their colleagues clamored for a chance to zap themselves.

That breakthrough, known as transcranial magnetic stimulation (TMS), led to the Food and Drug Administration's approval last month of the first noninvasive, non-pharmacological treatment for depression.

As a practical matter, approval of the device made by Neuronetics Inc., a five-year-old Malvern company, is intended for patients with major treatment-resistant depression who do not respond to any one medication. Millions of Americans fail to benefit from antidepressants, and millions more quit because of side effects.

Symbolically, the federal action is a big deal - another advance in a group of emerging fields that involve electrical stimulation of the brain.

"Our view of the brain is changing," said Mark S. George, a professor of psychiatry, radiology and neuroscience at the Medical University of South Carolina.

Just 10 or 15 years ago, scientists thought of the brain as a single entity - what he called "the brain-as-soup" model. "But really you want to treat specific regions in the brain."

George is editor in chief of a year-old journal named Brain Stimulation, and he is a champion for the cause. After decades of success with psychiatric drugs, he said, "we had forgotten that the brain is really an electrical organ."

Researchers worldwide are testing therapies ranging from highly invasive electrical implants to hardly noticeable magnetic fields on dozens of psychiatric and neurological disorders. Success has been limited - but so are current treatment options.

When a major depression enveloped Ernie Mercer in the late 1980s, Prozac had just come on the market, and it worked. When depression struck again five years ago, it didn't. Neither did Effexor or a third drug. Worse, they made him nervous and constipated.