Possible causes

There is also a significant positive correlation between those experiencing this disorder frequently and those suffering from narcolepsy. However, various studies suggest that many or most people will experience sleep paralysis at least once or twice in their lives.

Some report that various factors increase the likelihood of both paralysis and hallucinations. These include:

• Sleeping in a supine position (facing upwards)
• Irregular sleeping schedules; naps, sleeping in, sleep deprivation
• Increased stress
• Sudden environmental/lifestyle changes
• A lucid dream that immediately precedes the episode. Also conscious induction of sleep paralysis is a common technique to enter a state of lucid dreams.

Cultural references

• In Chinese folk culture, sleep paralysis is referred as "Guii Ya Chuarng" (鬼压床), literally: "Ghost press bed": 鬼: ghost, 压: press, 床: bed. The belief is that a spirit or ghost is sitting or lying on top of the individual while they were sleeping, causing the sleep paralysis. This is thought to be a minor body possession by the forces from the dead, and usually doesn't cause any harm to the victim.
• In India, there are two thoughts about sleep paralysis. One of the signs of approaching enlightenment is "witnessing sleep," that is to say, being lucid in sleep — such as with sleep paralysis. It was also believed within the movement that rakshasas (Hindu demons) may assail those making strides towards their own enlightenment and the good of all mankind. The other thought is a female entity, called Mohini (a demoness from the underworld), comes into the night-time world by means of ascending through a deep well. She is enchantingly beautiful, yet simultaneously horrific, unearthly, and deadly. Like her British Isles counterparts, she also seeks a male lover and human genetic material, presumably for the purpose of bearing a hybrid demon/human child.
• In Japan, sleep paralysis is referred to as kanashibari (金縛り, literally: "bound or fastened in metal": kana: metal, shibaru: to bind, tie, fasten")
• In Newfoundland, as a visit from the "old hag" (Ag Rog)
• In Mexico, as subida del muerto (the dead climbing on top)
• In Turkish, as karabasan (black buster)
• In Hazaragi, as Syahi Zer Kado (pressing ink)
• In the Southern United States, people have described it as "The witch riding your back"
• In Korea, it is referred as Gawinullim, literally in English: "To be pressed by Gawi." The meaning of Gawi is unclear but generally known to mean "spirits" or "demons." Another word in Korean "Gawi" is a homonym that means "scissors", which creates confusion for the accurate meaning of the word.
• In Indonesia, Javanese peoples called it "tindhihen" (To be seated upon)
• In Philippines, Sleep paralysis is often associated with Bangungot.
• In Vietnam, sleep paralysis is known as "ma đè", meaning a ghost or spirit lying on top of or pressing down on the person.
• In the West Indies, being "ridden by a duppy"
• In medieval times of Europe, attacks of sufferers of sleep paralysis may have given rise to the belief in mara, incubi, succubi, other demons and witchcraft.
• In traditional Russian belief symptoms reminiscent of sleep paralysis were attributed to the anger of domovoi, the home spirit, punishing people for bad husbandship or betrayal.
• According to traditional Hmong beliefs, various states of sleep paralysis are thought to be the processes in which an evil spirit or demon sits down on a person usually in retaliation to wrongdoings. Some Hmong have deemed it as the process of getting 'squashed'.
• Some scientists believe that many supposed occurrences of alien abduction, out-of-body travel, and other seemingly paranormal events may actually be due to misinterpreting the sensory effects of sleep paralysis.
• Others have argued that sleep paralysis might be the point of separation of the "dream body" from the physical body and out-of-body travel then begins.

Sleep paralysis in literature

An account can also be found in Ernest Hemingway's The Snows of Kilimanjaro, in which death approaches and sits upon the narrator's chest so that he cannot breathe.

See also

• Hypnagogic hallucinations
• Rapid eye movement (REM)
• Sleep
• Night terror
• Nightmare
• False awakening
• Lucid dreaming

Notes