Narcolepsy is a distinctive but underdiagnosed disorder of sleep and waking. Its cardinal manifestations are: (a) excessive daytime sleepiness, with a tendency to nap repeatedly through the day; (b) cataplexy, a loss of muscle tone triggered by emotion, causing immobility for seconds to minutes; (c) hypnagogic hallucinations, vivid visual or auditory phenomena, experienced at the onset of sleep; and (d) sleep paralysis, an inability to move on first awakening.1

When a patient describes all these symptoms the diagnosis should be straightforward. Diagnostic difficulty arises when patients present with isolated symptoms, or if their story suggests some more familiar diagnosis. We report on three patients recently encountered in whom narcolepsy was initially mistaken for epilepsy. Indeed, Gelineau, the French physician who coined the term “narcolepsy” in 1880, was at pains to distinguish his novel disorder of sleep (narco from the Greek for “sleep” and “lepsy” for taken hold by) from epilepsy, with which he thought it might be confused. 2 3