There are also more insidious effects: Many narcoleptics experience vivid hallucinations while falling asleep, and between 60% and 90% suffer from a dangerous condition called cataplexy, in which muscles become spontaneously paralyzed.
Traditionally, doctors have had to treat all these symptoms individually, giving patients a stimulant like Cephalon 's (nasdaq: CEPH - news - people ) Provigil or Novartis ' (nyse: NVS - news - people ) Ritalin to stave off sleepiness and then adding an antidepressant to try to prevent cataplexy.