What are the origins of sleep paralysis in folklore?
In 1664, a Dutch physician recorded the case of a petrified woman who awoke from sleep unable to move. “She believed the devil lay upon her and held her down, lying as a weight upon her breast,” he wrote[1]. Her cries went unanswered as she lay paralyzed, convinced she was under a witch’s grip. Nearly four centuries later, the feeling hasn’t changed; only the names and stories have. What science now calls sleep paralysis — a temporary mix-up of REM atonia and wakefulness — was once universally explained by demons and ghosts. Today it is estimated that roughly 30% of people worldwide experience this terror at least once[2]. Yet in the throes of an episode, victims across the globe swear they are being pressed down by some evil presence[1][3].
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The local specter depends on locale. On the islands of Zanzibar and Pemba it is Popobawa — a shapeshifting batlike demon which supposedly prowls villages at election time[4]. In Japan it is kanashibari, literally “bound in metal,” a name whose kanji combine kana (metal) and shibari (to bind)[5][6]. In China it is the infamous 鬼压身 (guǐ yā shēn), “ghost pressing on body”[7][8]. Even within the same society multiple names abound — Mexicans say “se me subió el muerto” (a dead man climbed on top of me)[9], Brazilians fear the pisadeira crone on rooftops[10][11], and Midwesterners in the United States still speak of the “Old Hag” sitting on one’s chest[7]. All of these traditions describe the same nightmare: waking, paralyzed, and sure that something fiendish is crushing you.
Yet the physics behind this ancient phenomenon is mundane. Sleep paralysis happens when the brain’s REM-sleep paralysis persists into wakefulness[12][13]. In other words, the mind is conscious enough to perceive the bedroom — the hush, the distant traffic, the whiskers of moonlight on the wall — but the body remains locked in REM sleep atonia, so utterly motionless that one might as well be dreaming. Ordinary REM atonia prevents us from acting out our dreams, but here that paralysis reaches into wakefulness[12][13]. No wonder most sufferers hallucinate a presence in the room — an intruder shape or shadow demanding, often unknowingly, to be taken seriously. Washington State psychologist Brian Sharpless notes that “even though every culture puts its own stamp on it, the core experiences are similar,” and the most common hallmarks — chest pressure, a sense of suffocation, visible apparitions — repeat worldwide[3][7].
The Bat-Man of Zanzibar
The legend of Popobawa (Swahili for “bat wing”) has origins as recent as the late 20th century. According to historian Tanya Daly, the first recorded Popobawa “sightings” emerged in Pemba around 1965, shortly after the island’s political revolution[14]. Sporadic rumors followed, but the creature truly tormented Zanzibar in a panic of 1995, followed by outbreaks in 2000 and again in 2007[14][4]. Eyewitnesses—usually terrified men—claimed a form-shifting entity invaded homes at night. Some said it came as a man, some as a bat, others as a dog or cat, then “morphed midway”[15]. Victims reported the full spectrum of demonic assault: overactive poltergeist phenomena, invisibly ravaging limbs and walls, and worst of all, violent sexual attack (often described as anal rape)[15].
In scholarly accounts Popobawa is often the “incubus” of Zanzibar. Its victims claim to wake paralysed on their backs, unable to scream as a sinister weight pins them. In folklore the demon targets skeptics and non-believers especially, under threat of repetitive visits if they deny its existence[4]. Many islanders believe one must talk about the attack or the creature will return; others vigilantly guard themselves by sitting around bonfires or even staying outdoors on election nights. Rumors link Popobawa’s rage to politics: notably, panic rises around every election[4]. One explanation holds that Popobawa is the vengeful ghost of assassinated President Abeid Karume, or a jinn summoned by his party[4]. (Anthropologist Daromir Jasiński noted that, because Zanzibar was a hub of Arab and African slave trade, Popobawa’s tale may also be a “social memory” of those historical horrors[16].)
Locally, people have devised their own rituals. Villagers report chanting Qur’anic verses or performing exorcisms on stalks of fig tree, placing charms beneath the roots, even sacrificing goats to appease the spirit[17]. But scientific observers see a different culprit. Skeptical investigator Benjamin Radford, after interviewing victims, found no physical evidence of any creature[18]. In 1995 journalist Joe Nickell compared the Popobawa encounter to the classic waking-dream scenario: extreme paralysis accompanied by terrifying content[19]. In short, it’s the same REM glitch seen from Quito to Quebec. Radford and Nickell concluded Popobawa is “a cultural phenomenon, not a real creature”[18]. In other words, the dread was real — but the monster was not. For most inhabitants, however, such rationalizations feel cold. To them the specter is all too real, a nightly terror to be reckoned with.
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Bound in Metal: Japan’s Kanashibari
Thousands of miles from Zanzibar, in Tokyo or Kyoto, sleep paralysis wears another mask. The Japanese call it kanashibari (金縛り), a term with literally the same meaning as its symptom: “bound by metal”[5][6]. Originating in medieval Buddhist esoteric practice, kanashibari was the name of a prayer that could immobilize malevolent spirits or exorcise yokai. In fact, old temple scrolls describe chanting spells to fix a demon in place — exactly what someone feels when they lie awake, rigid as stone[6]. Kanashibari has long been the mundane label for the phenomenon. Like Popobawa, the being behind it can be any jinn or yokai: trickster foxes (kitsune), the mischievous makuragaeshi (“pillow flipper” spirit), even the shapeshifting tanuki dog. Popular lore even credits Buddhist guardian deities with intervening: statues of Fudō Myōō (the Immovable One) are said to bind dark forces, giving the tradition its name.
In modern Japan, many people simply accept the name kanashibari as medical shorthand. Surveys show about one-third of adults admit to having experienced it[20], correlating with factors like death anxiety and external locus of control. When asked, some will attribute it to the supernatural, but most describe it as a family affair: “My mother said her mother used to say it was because of karma or a curse,” one student explained in a recent survey. Remedies vary: some slack a futon by tossing it on the floor (literally “flipping the pillow” to confuse the pillow thief); others perform a Shinto purification, others place a shōju (incense) at the bedside to calm roaming spirits.
The Ghost of Oppression in China and Beyond
East Asian cultures have their own iconic narrative. In China today, sleep paralysis is still widely known as guǐ yā shēn/chuáng (鬼压身/床), “ghost pressing on the body/bed”[7]. A classic case of ghost oppression was recorded in Hong Kong in 1994: 37% of undergraduates had felt the weight of an unseen intruder on their chests at least once[21]. Traditional Chinese explanations ranged from the hunch of an ancestral spirit to malevolent gui. In Hong Kong dialect it was a “nianqianggui” — literally a demon of the bed. By Taiwanese accounts it might even be a jealous neighbor’s curse.
Two decades ago, one survey found that nearly all Chinese (even psychiatrists) still recognized the term ghost oppression[22]. But superstition has waned. In a recent study of psychiatric out-patients, fewer than 1% blamed ghosts or spirits for their paralysis[22]. Instead, patients today cite fatigue or stress, much as Americans do. Modern medical advice in China focuses on healthy sleep routines, demystifying the attack as a benign REM mismatch. Yet popular belief still shapes language and folklore. Older villagers recite folk incantations or burn paper money to ward off hungry ghosts, while superstitious patients in rural clinics might don jade pendants overnight. In other parts of East Asia, the same syndrome is woven into local tales: the Phi Am spirit in Thailand, for example, is a female ghost who pummels sleepers on the chest, and in Korea the idiom gawi nulim (가위눌림) literally means “pressed by a gawi (incubus)”[23]. None of these cultural boxes change the fact: underneath every gui ya shen, karabasan, or dab tsog is the brain’s REM atonia awakening.
A World of Night Hag and Crone
Move west to the Atlantic or the Mediterranean, and the demons again take vivid forms. In Newfoundland and Cape Breton, the Old Hag is a wizened witch said to creep into bedrooms, straddle the sleeper, and slowly choke the breath out of them. Sailors passing in the night whisper of the old woman who perches on rigging. Nearly identical figures appear from Appalachia to the old English shires, often called “hag rides” or “night air rides.” The name “nightmare” itself derives from the Proto-Germanic marō — a malicious female spirit thought to sit on chest and suffocate sleepers[24][25]. The Catholic inherited imagery was the incubus and succubus — demonic seducers who visited sleeping men and women alike. Even today, Russian babushkas invoke the mara, Bulgarians the noćnik, and Algerians the karab djemel, each tale featuring an old crone or devil pressing down on victims.
In Southern Europe the motif appears too. The Catalan pesanta is a demonic black dog that can lie across you like a living iron weight[26]. The Portuguese and Brazilian pisadeira, as noted, is a bony old woman with long nails, who watches rooftops for genteel gluttons to prey upon[10][11]. (“She steps,” as her name from pisar hints[27].) Morocco and Egypt have the jinn al-mawta, ghost-demons of the dead, while in Turkic lands a Karabasan (literally “black presser”) comes as a black-hatted ifrit that invades dream. Folklore even sees familiar animals at fault: in the Andes a toad might suck out a man’s breath, in the Arctic an owl spirit, and in Polynesia a kana tevoro goblin.
A few examples from Africa remind us that the theme is global. West African Yoruba call it ogun oru (“night warfare”) — an invasion where the sleeper’s mortal spouse battles a spirit-spouse in dreams, only exorcism and prayer can end it[28]. Nigeria’s Hausa speak of dannau, “the devil on your back.” Among the Hmong of Southeast Asia, the dab tsog (crushing nightmare ghost) is so feared that in refugee camps it has been blamed for sudden nocturnal deaths[29]. A traditional Hmong shaman might be summoned to chase it out with chants and machetes. In Japan’s Ryukyu islands, local terms like kanashi-bari blend with the mainstream kanashibari myths, while even Inuit elders in Canada have a word (uqumangirniq) for a spirit afflicting the vulnerable sleeper[30]. The essentials of the story remain the same everywhere — helplessness, surreality, and the suggestion that something unseen is involved.
Folklore as Cultural Mirror
These tales carry hidden meaning. They often reflect collective anxieties or morals. The Brazilian Pisadeira, for instance, traditionally preys on those who slept on their backs after a large meal. In folklore her long iron nails are a cautionary emblem of greed and gluttony: parents warn children not to overeat lest the pisadeira steal them away[31][11]. In Zanzibar Popobawa is often portrayed as punishing liars and nonbelievers, and its electoral fever is read by some as proxy for political guilt or social unrest. Lilith, the ancient Mesopotamian night monster of Jewish legend, illustrates this pattern: a sexual demon who preyed on infants and mothers, Lilith became a figure to blame for miscarriages; to this day some Jewish communities hang amulets in maternity wards to ward off “Lilith of the night”[32]. In Greece the 2nd-century doctor Galen named sleep paralysis pan ephialtes (“Pan that jumps upon you”) after the satyr-god Pan — a glib warning that even divine tricksters might lie behind irrational fear[33].
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Sometimes the story reveals cultural contact: Zanzibar’s Popobawa, a blend of Arabic, African, and colonial influences, may encode memories of the slave-trade era[16]. Thailand’s phi am stems from Southeast Asian ghost lore but was also influenced by wider Buddhist concepts of restless spirits. The Anglo-American “Old Hag” is famously syncretic, merging Norse mara, Celtic witch myths, and even early scientific rabblings about unexplained fainting. Even language carries clues: the Proto-Indo-European root of “mare” (mar- meaning to harm) is cognate across Europe, subtly linking them all to the same nightmare demon[25]. In sum, folklore casts sleep paralysis as moral theatre — a sin to confess, a ghost to placate — for centuries before medicine could explain it.
From Superstition to Science
Today we know that sleep paralysis is a mixed signal in the brain. During healthy REM sleep we experience vivid dreams and complete muscle atonia, safeguarding us from acting them out. In an SP episode the cortex becomes wakeful prematurely, but the pons and medulla still suppress motor neurons. Hence the horror: the mind is awake, often as the amygdala lights up to fear mode, and yet the body remains fast asleep, limbs locked in place[12][13]. Hallucinations of an intruder or pressure are probably generated by a hyper-active fear center unable to move. Scientists have even mapped the paralytic phenomenon to genetic variants (for instance, a link to a circadian gene PER2 has been noted), but the key point is this: it’s a benign spasm of normal physiology, not a curse[13][34].
Clinically, sleep paralysis is categorized under REM parasomnias. Surveys vary, but a large 2023 study of nearly 7,000 people confirmed common findings: younger age, erratic sleep, and psychological stress make episodes more likely[35][36]. People with PTSD, panic or anxiety disorders and those with sleep disorders like apnea or narcolepsy report higher rates[37][36]. It causes great terror but no direct harm. Health experts advise simple remedies: improve sleep hygiene, manage stress, and if needed treat underlying conditions. Some suggest sleeping on one’s side rather than the back (so the weight isn’t literally on the chest). Pillows propping the upper body slightly, relaxation exercises, and even hitting the bed or stretching during an episode can help snap out of it. No pill is made specifically for SP, though in chronic cases doctors sometimes prescribe antidepressants or GABAergic agents to stabilize REM sleep.
Rituals of Relief
Despite science, traditional rituals persist. Ever practical, many sufferers do what ancestors did. For example, in Muslim cultures it is common to recite passages from the Qur’an at the bedside during an episode. One guidebook notes that to banish the Turkish karabasan, one should recite the chapters Al-Falaq and An-Nas[38]. In parts of South Asia, if someone speaks of being pressed by a ghost (bakhtak in Urdu, boba in Bengali), relatives may tie a holy thread around the person’s waist, lie with them to “push back” the spirit, or summon an imam for an exorcism (often involving verses and spitting of water)[39]. In Japan, some still invoke Fudō Myōō’s image or chant Shinto prayers. New Englanders might cross themselves or utter a Hail Mary, while African Americans might turn to a Black preacher’s prayers — a fact noted by 19th-century researchers who recorded stories of communal church gatherings where sufferers were prayed over until they could move again. In rural Nigeria, Christian believers often wave crosses or dump salt on the floor, referencing traditional kingship rites for cleansing evil. In Zambia or Bangladesh, shamans may be brought in, offering drumming and chants to chase away the dab tsog or naniot ghost. Even in secular societies, strange strategies surface: some people report leaving a coin under the pillow (a folk talisman), or sleeping with a small light on, hoping the intruder flees daylight.
Today’s experts emphasize compassion. Many people who endure these episodes never mention them, embarrassed or convinced they are going mad. Brian Sharpless wryly quotes patients thinking “Doc, I felt like there was a demonic dwarf sitting on my chest”[40]. Yet raising awareness is crucial: by learning it’s a common brain quirk, patients find relief from the isolation and fear. Sleep specialists note that empathic listening and education go a long way. In fact, one recent medical review urges doctors to “empathetically address the patient’s concerns and scientifically, yet sensitively, help dispel myths”[37][35].
This clash of modern science and ancient myth often reveals more than just nightmares. As psychiatry connects SP to wider themes — PTSD, cultural stress, family history — it also acknowledges that folklore has some value. Vampires and witches may not be real, but they speak to how communities conceptualize helplessness, shame, or collective guilt. To a person who has just felt the crushing grip of a popobawa, the demon is real. Western rationalists might chafe at the term “collective panic,” but to those villagers it was as physical as any disease. Likewise, to a Japanese student cradling her chest in terror, kanashibari is as tangible as an exam smear. In the end, every ghost story around the world is telling us the same thing: there is something about being alive, vulnerable on the brink of consciousness, that terrifies us to the core.
Whether we call it Popobawa, kanashibari, pisadeira or the Old Hag, the nightmare is ancient and unifying. It is at once intensely personal and profoundly cultural. And as science makes it less mysterious, it leaves us with the choice of what meaning to take. Perhaps, as one scholar suggests of Popobawa, the tales are less about a literal bat-demon and more about “Tanzanian talk” — a way for people to express their fears in language they share[41]. In sleep paralysis, the midnight visitor may recede, but its imprint on our stories remains: a reminder of the midnight mysteries our ancestors faced, and the ones we still grapple with when the lights go out.
