Psychiatrist Finds Clues to Nerve Defect in Narcolepsy

A UCLA psychiatrist has found the first clues to the mechanism of narcolepsy, the mysterious sleeping disorder that affects more than 250,000 Americans, causing them to lapse into sleep at inappropriate moments. They also have a characteristic muscle problem called cataplexy, a loss of muscle tone--often leading to collapse--caused by sudden excitement or even laughing.

Working with a dog model of the disease, Dr. Jerome M. Siegel found that the first step in the disease is the degeneration of axons, the long, filament-like extensions of nerve cells that make contact with other cells. He told a meeting of the Society for Neuroscience in San Diego that the degeneration occurs specifically in cells that control both motor functions and sleep, and that the degenerated cells are slowly removed by the brain, leaving no evidence that can be discovered at autopsy.