Sleep paralysis

The Nightmare, by Henry Fuseli (1781) is thought to be one of the classic depictions of sleep paralysis perceived as a demonic visitation.

Sleep paralysis is paralysis associated with sleep that may occur in normal subjects or be associated with narcolepsy, cataplexy, and hypnagogic hallucinations. The pathophysiology of this condition is closely related to the normal hypotonia that occur during REM sleep.^[1] When considered to be a disease, isolated sleep paralysis is classified as MeSH D020188.^[2] Some evidence suggests that it can also, in some cases, be a symptom of migraine.^[3][4]

Symptoms and characteristics

Physiologically, sleep paralysis is closely related to REM atonia, the paralysis that occurs as a natural part of REM (rapid eye movement) sleep. Sleep paralysis occurs either when falling asleep, or when awakening. When it occurs upon falling asleep, the person remains aware while the body shuts down for REM sleep, and it is called hypnagogic or predormital sleep paralysis. When it occurs upon awakening, the person becomes aware before the REM cycle is complete, and it is called hypnopompic or postdormital.^[5] The paralysis can last from several seconds to several minutes "by which the individual may experience panic symptoms".^[6] (described below) As the correlation with REM sleep suggests, the paralysis is not entirely complete; use of EOG traces shows that eye movement is still possible during such episodes.^[7] When there is an absence of narcolepsy, sleep paralysis is referred to as isolated sleep paralysis (ISP).^[8]

In addition, the paralysis may be accompanied by terrifying hallucinations (hypnopompic or hypnagogic) and an acute sense of danger.^[9] Sleep paralysis is particularly frightening to the individual because of the vividness of such hallucinations.^[8] The hallucinatory element to sleep paralysis makes it even more likely that someone will interpret the experience as a dream, since completely fanciful or dream-like objects may appear in the room alongside one's normal vision. Some scientists have proposed this condition as an explanation for alien abductions and ghostly encounters.^[10] A study by Susan Blackmore and Marcus Cox (the Blackmore-Cox study) of the University of the West of England supports the suggestion that reports of alien abductions are related to sleep paralysis rather than to temporal lobe lability.^[11]

Possible causes

Several studies have concluded that many or most people experience sleep paralysis at least once or twice in their lives. A study conducted by Sedaghat F. et al. has investigated the prevalence of sleep paralysis among Iranian medical students. 24.1% of students reported experiencing sleep paralysis at least once in their lifetime. The same result was reported among Japanese, Nigerian, Kuwaiti, Sudanese and American students.^[12]

Many people who commonly enter sleep paralysis also suffer from narcolepsy. In African Americans, panic disorder occurs with sleep paralysis more frequently than in Caucasian Americans.^[13] Some reports read that various factors increase the likelihood of both paralysis and hallucinations. These include:

• Sleeping in a face upwards or supine position
• Irregular sleeping schedules; naps, sleeping in, sleep deprivation
• Increased stress
• Sudden environmental/lifestyle changes
• A lucid dream that immediately precedes the episode.
• Excessive consumption of alcohol coupled with lack of adequate sleep.^[14]

Treatment

Treatment starts with patient education about sleep stages and about the muscle atonia that is typically associated with REM sleep. For most healthy individuals, avoiding chronic sleep deprivation is enough to relieve symptoms. It is recommended that patients be evaluated for narcolepsy if symptoms persist.^[15]

Related phenomena

Many perceptions associated with sleep paralysis (visceral buzzing, loud sounds, adrenal mental state, presences, and the paralysis itself) also constitute a common phase in the early progression of episodes referred to as out of body experiences.^[16][17] Mental focus varies between the two conditions; paralysis sufferers tend to fixate on reestablishing operation of the body, whereas subjects of out-of-body episodes are more occupied by perceived non-equivalence with the body.

Folklore

The original definition of sleep paralysis was codified by Dr. Samuel Johnson in his A Dictionary of the English Language as "nightmare," a term that evolved into our modern definition. Such sleep paralysis was widely considered to be the work of demons and more specifically incubi, which were thought to sit on the chests of sleepers. In Old English the name for these beings was mare or mære (from a proto-Germanic *marōn, cf. Old Norse mara), hence comes the mare part in nightmare. The word might be etymologically cognate to Hellenic Marōn (in the Odyssey) and Sanskrit Māra.

Folk belief in Newfoundland, South Carolina and Georgia describe the negative figure of the Hag who leaves her physical body at night, and sits on the chest of her victim. The victim usually wakes with a feeling of terror, has difficulty breathing because of a perceived heavy invisible weight on his or her chest, and is unable to move i.e., experiences sleep paralysis. This nightmare experience is described as being "hag-ridden" in the Gullah lore. The "Old Hag" was a nightmare spirit in British and also Anglophone North American folklore.

In Fiji the experience is interpreted as "kana tevoro" being 'eaten' or possessed by a demon. In many cases the 'demon' can be the spirit of a recently dead relative who has come back for some unfinished business, or has come to communicate some important news to the living.

In Nigeria, "ISP appears to be far more common and recurrent among people of African descent than among whites or Nigerian Africans",^[6] and is often referred to within African communities as "the Devil on your back."^[18][19][20]

Various forms of magic and spiritual possession were also advanced as causes. In nineteenth century Europe, the vagaries of diet were thought to be responsible. For example, in Charles Dickens's A Christmas Carol, Ebenezer Scrooge attributes the ghost he sees to "... an undigested bit of beef, a blot of mustard, a crumb of cheese, a fragment of an underdone potato..." In a similar vein, the Household Cyclopedia (1881) offers the following advice about nightmares:

"Great attention is to be paid to regularity and choice of diet. Intemperance of every kind is hurtful, but nothing is more productive of this disease than drinking bad wine. Of eatables those which are most prejudicial are all fat and greasy meats and pastry... Moderate exercise contributes in a superior degree to promote the digestion of food and prevent flatulence; those, however, who are necessarily confined to a sedentary occupation, should particularly avoid applying themselves to study or bodily labor immediately after eating... Going to bed before the usual hour is a frequent cause of night-mare, as it either occasions the patient to sleep too long or to lie long awake in the night. Passing a whole night or part of a night without rest likewise gives birth to the disease, as it occasions the patient, on the succeeding night, to sleep too soundly. Indulging in sleep too late in the morning, is an almost certain method to bring on the paroxysm, and the more frequently it returns, the greater strength it acquires; the propensity to sleep at this time is almost irresistible."^[21]

Around the world

Complete references to many cultures are given in the References section

East Asia

• In Chinese culture, sleep paralysis is widely known as "鬼壓身/鬼压身" (pinyin: guǐ yā shēn) or "鬼壓床/鬼压床" (pinyin: guǐ yā chuáng), which literally translate into "ghost pressing on body" or "ghost pressing on bed." A more modern term is "夢魘/梦魇" (pinyin: mèng yǎn).
• In Japanese culture, sleep paralysis is referred to as kanashibari (金縛り, literally "bound or fastened in metal," from kane "metal" and shibaru" to bind, to tie, to fasten"). This term is occasionally used by English speaking authors to refer to the phenomenon both in academic papers and in pop psych literature.^[22]
• In Korean culture, sleep paralysis is called gawee nulim (Hangul: 가위눌림), literally meaning "being pressed down by scissors". It is often associated with a superstitious belief that a ghost or spirit is laying on top of or pressing down on the sufferer.

South-East Asia

• In Cambodian, Laotian, and Thai culture, sleep paralysis is called phǐǐ am and khmout sukkhot. It is described as an event in which the person is sleeping and dreams that one or more ghostly figures are nearby or even holding him or her down. The sufferer usually thinks that he or she is awake but unable to move or make any noises. This is not to be confused with pee khao and khmout jool, ghost possession.
• In Hmong culture, sleep paralysis describes an experience called "dab tsog" or "crushing demon." Often the sufferer claims to be able to see a tiny figure, no larger than a child, sitting on his or her chest. What is alarming is that a vast number of American Hmong have died in their sleep, prompting the Centers for Disease Control to create the term "Sudden Unexpected Nocturnal Death Syndrome" (see Sudden unexplained death syndrome) or "SUNDS" for short; this is now theorized to be a form of Brugada syndrome.
• In Vietnamese culture, sleep paralysis is referred to as "ma đè", meaning "held down by a ghost" or "bóng đè", meaning "held down by a shadow".
• In Philippine culture, "bangungut", or sudden unexplained death syndrome, has traditionally been attributed to nightmares.^[23] People who have claimed to survive such nightmares have reported experiencing the symptoms of sleep paralysis.
• In New Guinea, people refer to this phenomenon as "Suk Ninmyo", believed to originate from sacred trees that use human essence to sustain its life. The trees are said to feed on human essence during night as to not disturb the human's daily life, but sometimes people wake unnaturally during the feeding, resulting in the paralysis.
• In Malay of Malay Peninsula, sleep paralysis is known as 'kena tindih' (or 'ketindihan' in Indonesia), which means "being pressed".^[24] Incidents are commonly considered to be the work of a malign agency; occurring in what are explained as blind spots in the field of vision, they are reported as demonic figures.

South Asia

• In the Muslim culture of South Asia (Pakistani, Bangladeshi, Indian Muslims), sleep paralysis is considered to be an encounter with evil jinns and demons who have taken over one's body. In northwestern Pakistan, this ghoul is known as 'bakhtak' (Urdu: بختک). It is also assumed that it is caused by the black magic performed by enemies and jealous persons. Spells, incantations and curses could also result in ghouls haunting a person. Some homes and places are also haunted by evil ghosts, satanic or other supernatural beings and they could haunt people living there. Sufis, Mullahs, Faqirs or Imams perform exorcism on individuals who are possessed. Talismans and Amulets are worn by people to keep them safe especially the young children. The homes, houses, buildings and grounds are blessed and consecrated by Sufis, Mullahs or Imams by reciting Qur'an and Adhan (Urdu: أَذَان), the Islamic call to prayer, recited by the muezzin.
• In Tamil and Sri Lankan Culture, this particular phenomenon is referred to as 'Amuku Be" or 'Amuku Pei' meaning "the ghost that forces one down".
• In Nepal, especially Newari culture it is also known as 'Khyaak' a ghost-like figure believed to reside in the darkness under the staircases of a house.

Middle-East, Western and Central Asia

• In Arabic Culture, sleep paralysis is often referred to as Kaboos' (Arabic: كابوس‎), literally "presser" or Ja-thoom (Arabic: جاثوم‎) literally "What sits heavily on something. Though the term Kaboos is also used to refer to any form of bad dreams. In folklore across Arab countries, the Kaboos is believed to be a shayṭān or a ‘ifrīt which sits, heavily, on people's chests.
• In Turkish culture, sleep paralysis is often referred to as "karabasan" ("The dark presser/assailer"). It is believed to be a creature that attacks people in their sleep, pressing on their chest and stealing their breath. However, folk legends do not provide a reason why a shaytan or ifrit does that.
• In Persian culture it is known as 'bakhtak' (Persian: بختک), which is a ghost-like black creature that sits on the dreamer's chest, making breathing hard for him/her.

Africa

• In African culture, isolated sleep paralysis is commonly referred to as "the witch riding your back".^[18][25]
• Several studies have shown that African-Americans may be predisposed to isolated sleep paralysis also known as "the witch is riding you" or "the haint is riding you".^[20] In addition, other studies have shown that African-Americans who have frequent episodes of isolated sleep paralysis, i.e., reporting having one or more sleep paralysis episodes per month coined as "sleep paralysis disorder," were predisposed to having panic attacks.^[26] This finding has been replicated by other independent researchers^[27][28].
• Ogun Oru is a traditional explanation for nocturnal disturbances among the Yoruba of Southwest Nigeria; ogun oru (nocturnal warfare) involves an acute night-time disturbance that is culturally attributed to demonic infiltration of the body and psyche during dreaming. Ogun oru is characterized by its occurrence, a female preponderance, the perception of an underlying feud between the sufferer's earthly spouse and a 'spiritual' spouse, and the event of bewitchment through eating while dreaming. The condition is believed to be treatable through Christian prayers or elaborate traditional rituals designed to exorcise the imbibed demonic elements.^[29]
• In Zimbabwean Shona culture the word Madzikirira is used to refer something really pressing one down. This mostly refers to the spiritual world in which some spirit—especially an evil one—tries to use its victim for some evil purpose. The people believe that witches can only be people of close relations to be effective, and hence a witches often try to use one's spirit to bewitch one's relatives.
• In Ethiopian culture the word 'dukak' is used, which is believed to be an evil spirit that possesses people during their sleep. Some people believe this experience is linked to use of Khat ('Chat'). Khat users experience sleep paralysis when suddenly quitting chewing Khat after use for a long time.
• In Swahili speaking East Africa, it is known as 'jinamizi', which refers to a creature sitting on one's chest making it difficult for him/her to breath. It is attributed to result from a person sleeping on his back. Most people also recall being strangled by this 'creature'. People generally survive these 'attacks'

Europe

• In Hungarian folk culture sleep paralysis is called "lidércnyomás" ("lidérc pressing") and can be attributed to a number of supernatural entities like "lidérc" (wraith), "boszorkány" (witch), "tündér" (fairy) or "ördögszerető" (demon lover).^[30] The word "boszorkány" itself stems from the Turkish root "bas-", meaning "to press".^[31]
• In Iceland folk culture sleep paralysis is generally called having a "Mara". A goblin or a succubus (since it is generally female) believed to cause nightmares (the origin of the word 'Nightmare' itself is derived from her name). Other European cultures share variants of the same folklore, calling her under different names; Proto-Germanic: marōn; Old English: mære; German: Mahr; Dutch: nachtmerrie; Icelandic, Old Norse, Faroese, and Swedish: mara; Danish: mare; Norwegian: mare; Old Irish: morrigain; Slovene: môra; Bulgarian, Croatian, Serbian, Polish: mora; French: cauchemar; Romanian: moroi; Czech: můra. The origin of the belief itself is much older and goes back to the reconstructed Proto Indo-European root mora-, an incubus, from the root mer- "to rub away" or "to harm".
• In Malta, folk culture attributes a sleep paralysis incident to an attack by the "Haddiela" who is the wife of the "Hares", an entity in Maltese folk culture that haunts the individual in ways similar to a poltergeist. As believed in folk culture, to rid oneself of the Haddiela, one must place a piece of silverware or a knife under the pillow prior to sleep.
• In Greece and Cyprus, it is believed that sleep paralysis occurs when a ghost-like creature or Demon named Mora, Vrachnas or Varypnas (Greek: Μόρα, Βραχνάς, Βαρυπνάς) tries to steal the victim's speech or sits on the victim's chest causing asphyxiation.

Americas

• During the Salem witch trials several people reported nighttime attacks by various alleged witches including Bridget Bishop that may have been the result of sleep paralysis.^[32]
• In Mexico, it is believed that this is caused by the spirit of a dead person. This ghost lies down upon the body of the sleeper, rendering him unable to move. People refer to this as "Subirse el Muerto" (Dead Person on you).
• In many parts of the Southern United States, the phenomenon is known as a "hag", and the event is said to often be a sign of an approaching tragedy or accident.
• In Newfoundland and Labrador, it is known as the 'Old Hag'.^[33] In island folklore, the Hag can be summoned to attack a third party, like a curse. In his 1982 book, The Terror that Comes in the Night, David J. Hufford writes that in local culture the way to call the Hag is to recite the Lord's Prayer backwards. It is also common for believers to claim that those who are not wakened from this paralysis will die.
• In contemporary western culture it is believed that the phenomenon of reported Alien abduction is caused by sleep paralysis where the hallucination of aliens has been generated by 20th and 21st century science fiction.^[34]

Notes

References

• Culhane-Pera, Kathie (2003). Healing by Heart: Clinical and Ethical Case Stories of Hmong Families and Western Providers. Vanderbilt University Press.
• Bower, Bruce (July 9, 2005). "Night of the Crusher." Science News.
• Conesa, J. (2000). Geomagnetic, cross-cultural and occupational faces of sleep paralysis: An ecological perspective. Sleep and Hypnosis, 2, (3), 105-111.
• Conesa, J. (2002). Isolated Sleep Paralysis and Lucid Dreaming: Ten-year longitudinal case study and related dream frequencies, types, and categories. Sleep and Hypnosis, 4, (4), 132-143.
• Conesa, J. (2003). Sleep Paralysis Signaling (SPS) As A Natural Cueing Method for the Generation and Maintenance of Lucid Dreaming. Presented at The 83rd Annual Convention of the Western Psychological Association, May 1–4, 2003 in Vancouver, BC, Canada.
• Conesa-Sevilla, Jorge (2004). Wrestling With Ghosts: A Personal and Scientific Account of Sleep Paralysis. Pennsylvania: Xlibris/Randomhouse.
• Cooke, William H.. Justice at Salem: Reexamining the Witch Trials. Undertaker Press, Annapolis. 2009 ISBN 1-59594-322-6
• Firestone M. The “Old Hag”: sleep paralysis in Newfoundland. The Journal of Psychoanalytic Anthropology 1985; 8:47-66.
• Fukuda K, Miyasita A, Inugami M, Ishihara K. High prevalence of isolated sleep paralysis: kanashibari phenomenon in Japan. Sleep 1987; 10:279-286.
• Hartmann E. The nightmare: the psychology and biology of terrifying dreams. New York:Basic,1984.
• Hufford D.J. The terror that comes in the night: an experience-centered study of supernatural assault traditions. Philadelphia:University of Pennsylvania Press, 1982
• Kettlewell, N; Lipscomb, S; Evans, E. (June, 1993). "Differences in neuropsychological correlates between normals and those experiencing "Old Hag Attacks'." Perceptual and Motor Skills. 76 (3 Pt 1): 839-45; discussion 846. PMID 8321596
• Ness RC. “The Old Hag” phenomenon as sleep paralysis: a bicultural interpretation. Culture, Medicine and Psychiatry 1978; 2:15-39.
• Ohayon MM, Zulley J, Guilleminault C, Smirne, S. Prevalence and pathologic associations of sleep paralysis in the general population. Neurology, 1999; 52:1194-1200.
• Sagan, Carl (1997). The Demon-Haunted World: Science as a Candle in the Dark.
• Schneck JM. Sleep paralysis and microsomatognosia with special reference to hypnotherapy. The International Journal of Clinical and Experimental Hypnosis 1977; XXV:72-77.
• Takeuchi T, Miyasita A, Sasaki Y, Inugami M, Fukuda K. Isolated sleep paralysis elicited by sleep interruption. American Sleep Disorders Association and Sleep Research Society, 1992; 15: 217-225.

External links

• Sleep information and links from Stanford University
• Sleep Paralysis and Associated Hypnagogic and Hypnopompic Experiences from University of Waterloo
• Waking Up to Sleep Paralysis