Ghosts, Aliens, and Black Magic: Sleep Paralysis Looks Different in Different Places 

Imagine waking up in pitch darkness to a slavering monster with blood dripping down its fangs. You try to cry out for help but can’t. You're paralyzed from head to toe!  Sleep paralysis—paralysis upon falling asleep or awakening often coupled with uncanny “ghost” sights—is surprisingly common yet steeped in mystery.

One in five people worldwide are affected by these visceral nightmares. But despite its prevalence, it has largely remained a riddle. For millennia, these visions have left diverse imprints on human culture, from ghost tales to space alien visits. Scientists have since dismissed such imaginative accounts, yet these ideas persist. In fact, my research done over a decade in seven different countries, shows that beliefs about sleep paralysis can radically impact the experience, illustrating a striking type of mind-body interaction.

Sleep paralysis is triggered by a basic brain glitch at the interface between wakefulness and rapid eye movement (REM) sleep. During REM you have crisp, life-like dreams. To prevent you from acting out these vivid dreams and hurting yourself, your brain temporarily incarcerates your entire body. This neural safety procedure is tightly controlled by a handful of chemicals released from the lower part of your brain that flip-flop you between sleep and wakefulness. This chemical switch works smoothly in a winner-take-all manner most of the time: either you remain in a deep slumber, or you awaken, fully conscious. But not always. Sometimes you wake up while still under the spell of REM paralysis, leaving you stuck in the middle of sleep and wakefulness. As if being paralyzed and unable to speak when waking up isn’t sufficiently nerve-racking, occasionally, the terrifying dreams of REM can “spill over” into conscious awakening, like dreaming with your eyes open. These baffling sights occurring around the edges of sleep have left helpless spectators horrified throughout history.

Indeed, as many as 40% of sleep paralysis sufferers hallucinate during the attack. These often involve seeing and sensing bedroom intruders that violently attacks, chokes and suffocate the sleeper by crushing his chest. Sometimes victims even report being “raped” by the ghostly creature.

These nocturnal encounters are interpreted differently around the globe. Each culture provides its own bizarre twist. In Egypt, my research shows that sleep paralysis is thought to be triggered by a jinn (a magic genie) that appears out of nowhere, terrorizing and sometimes killing its victims. In Italy, it’s an attack by the Pandafeche, an entity described as an evil witch or vicious giant cat. In South Africa, Indigenous people believe it to be caused by segatelelo, a form of black magic involving menacing dwarflike beings, known as tokoloshe; and in Turkey, it’s the karabasan—mysterious spirit-like creatures. Conversely, my work shows that Danish and Polish people provide a less spine-tingling account: they chiefly attribute the experience to physiological risk factors like dysfunction in brain and body.

These explanations—scientific and supernatural—can have a major say on how people experience sleep paralysis. When directly comparing sleep paralysis in Egypt and Denmark, my team and I found that Egyptians fear it much more than Danes do. That is, a staggering 50% plus Egyptians were convinced that their sleep paralysis could kill. Egyptians also believed that it lasted longer—and strikingly, they had it three times more often. Beliefs about sleep paralysis in Egypt seemed to have radically shaped their experience. Those who blamed supernatural forces were terrorized by the attack and paralyzed for longer. A pernicious pattern was unfolding: Coupled with certain beliefs, sleep paralysis had gone from a basic “brain glitch” to a chronic, prolonged, and potentially fatal, supernatural encounter.

Read More: Why Sleep Paralysis Makes You See Ghosts

The question naturally came up, could the findings be replicated? That is, could we possibly show, in another culture, that these beliefs about sleep paralysis, could exacerbate the experience. Italy was a good place to go hunting for scientific answers. Recall Italians also have florid ideas about the origin of sleep paralysis. According to one of our studies, over a third of people from Italy’s Abruzzo region believe their sleep paralysis may have been caused by the Pandafeche. Like Egyptians, we soon discovered that Italians also face sleep paralysis more frequently—nearly four times more often than Danes do—with prolonged paralysis and extreme fear. In both Italy and Egypt, beliefs about the condition amplified symptoms in an odd mind-body interaction. Indeed, imagination has had the striking ability to mold physiological experiences.

But how does it all work? In a nutshell, anxiety predisposes people, so that if you fear it, you’re also more likely to experience it, and the greater its effects are. A key clue comes from our finding that sleep paralysis is nearly twice as common in Egypt compared with Denmark. Likewise, Italians who think their sleep paralysis may have a supernatural origin are also more likely to hallucinate during the experience, including sensing a ghostly presence. When people in these cultures go to bed, they fear the “cultural creature” might attack them. Ironically, this fuels fear centers in the brain, making them more likely to wake up during REM and have sleep paralysis. Once they have sleep paralysis, they interpret it in light of their beliefs, which makes them even more scared. Put simply: once sleep paralysis is feared as a mythical monster, anxiety runs amok, triggering unwanted awakenings at night, and effectively, more sleep paralysis. This vicious cycle perpetually feeds into itself until sleep paralysis becomes chronic, prolonged and, even, potentially pathological.

Indeed, our discoveries suggest that sleep paralysis, if coupled with certain beliefs, isn’t just petrifying but also traumatizing. Intriguingly, in one study in Egypt, psychiatrist and researcher Devon Hinton and I found that people who’ve experienced it show greater signs of trauma and anxiety, relative to those who haven’t. Those with spooky visions—seeing creepy creatures, say—are at even greater risk. In another study in Italy, we found that horror during sleep paralysis, like fear of dying, seemed to trigger symptoms of trauma and depression. These results show us that when the experience is understood through a particular cultural filter, it highlights how thoughts can be dangerously powerful and shape brain and body—and how the nocebo effect (the placebo’s evil twin) works.

As we’re exploring sleep paralysis around the world, the riddle remains. Here is a condition that can make you see ghosts, witches, and menacing monsters, even exotic animals, of various flavors, depending on the corner of the globe you occupy. It shows how a singular phenomenon in science can leave a myriad of imprints on culture. And perhaps more importantly, it shows how our beliefs can color the very lens through which we view the world, illustrating the sometimes terrifying, power of human imagination.