What is the X in X-mas?
1880, from French narcolepsie, coined 1880 by French physician Jean-Baptiste-Édouard Gélineau (1859-1928) from comb. form of Greek narke "numbness, stupor" (see narcotic) + lepsis "an attack, seizure," from leps-, future stem of lambanein "take hold of, grasp" (see analemma). Related: Narcoleptic; narcolept.
narcolepsy nar·co·lep·sy (när'kə-lěp'sē)
A disorder characterized by sudden and uncontrollable, though often brief, attacks of deep sleep, sometimes accompanied by paralysis and hallucinations. Also called hypnolepsy.