Sleep paralysisSleep paralysis
) is a sleep disorder
in which the sufferer, about to fall asleep
(the hypnagogic state
) or upon just waking (the hypnopompic state
), and is unable to move, speak or otherwise cry out.
It is always reported as being a terrifying state, accompanied by feelings of helplessness, and one may feel a malevolent "presence," or the sensation of being held down or otherwise forcibly restrained. Loud noises may be heard; terror and dread are common. The paralyzed state may continue for several seconds or even minutes.
Many sufferers report very vivid hallucinations during this state. Some report hallucinating about being abducted by aliens and other paranormal experiences.
In Japan, sleep paralysis is referred to as kanashibari; in Canada, as a visit from the "old hag."
In medieval times, attacks of sufferrers of sleep paralysis may have given rise to the belief in incubi, succubi and other demons. Most people experience sleep paralysis once or twice in their lives, but it is common in those suffering from narcolepsy.
It is a well-described neurological condition, if often very frightening for those who experience it. There is no evidence of true paranormal phenomena associated with sleep paralysis.