A 22-year-old man presents to the sleep clinic with excessive daytime sleepiness. He reports frequently dozing off during lectures despite getting 7–8 hours of sleep at night. He also describes experiencing vivid dream-like hallucinations just before falling asleep and occasionally waking up unable to move for a few seconds. Upon further questioning, he recalls multiple episodes where he suddenly collapses to the ground after laughing but remains fully conscious during these episodes. Which of the following symptoms is most specific for narcolepsy?
