It turns out they may be based on actual health conditions.
Spooky, paranormal stories are inspired by strangeness in the world around us. Light in the night sky? Must be a UFO. Curious shape beneath the surface of the lake? Gotta be the Loch Ness Monster.
As these scary tales are passed between storytellers–preferably around a campfire–they snowball into haunting sagas that can completely derail what would have otherwise been a perfectly good night's sleep. But they all start somewhere, and in some cases, the origin stories are even more interesting than the legends themselves.
Case in point: The surprising medical history of vampires, witches, zombies, and other spooky characters that you're likely to encounter (at least in stories) this season.
The original "vampires" may have had a blood disorder
Legends of pale, blood-thirsty vampires emerging at night may be rooted in a disorder called erythropoietic protoporphyria. EPP is a condition that affects the body's ability to make heme, a crucial component of blood. (Heme is what gives blood its red color.) The condition causes chronic anemia, which can lead to pale skin and fatigue. People with EPP are also ultra-sensitive to UV light, and can develop painful blisters on their skin after too much time in the sun. Sound familiar?
Today, treatment for EPP involves blood transfusions, and staying inside during daylight hours. But it's possible that in ancient times, patients turned to animal blood to ease their symptoms, according to Boston Children’s Hospital, where researchers recently discovered a genetic mutation that triggers EPP.
The Salem "witches" may have had a fungal disease
Eight young women accused of being witches in the famous Salem trials of 1692 exhibited oddly similar symptoms, including hallucinations, convulsions, burning sensations, and temporary blindness. Experts now know that those symptoms are common among people with convulsive ergotism, or ergot poisoning, which is caused by a fungus that can grow on wheat, rye, and other similar grains.
The fungus loves warm and wet springs and summers, the PBS series Secrets of the Dead reported, which is what occurred in Salem in 1691, the year before these women were accused of witchcraft: "At that time, rye was the staple grain of Salem. The rye crop consumed in the winter of 1691-1692—when the first unusual symptoms began to be reported—could easily have been contaminated by large quantities of ergot. The summer of 1692, however, was dry, which could explain the abrupt end of the 'bewitchments."
"Werewolves" may have had excessive hair growth
One possible explanation behind tales of werewolves is a condition called hypertrichosis, which causes excessive hair growth (though it has nothing to do with a full moon). Hypertrichosis can affect any body part, and may even occur on the face. It's often referred to as "werewolf syndrome." Some people are born with it–called congenital hypertrichosis–while others have acquired hypertrichosis, meaning they developed it later in life as a side effect to a medication, a symptom of a hormone disorder, or as a response to malnutrition or even eating disorders.
Thankfully, the condition is exceedingly rare–researchers have documented fewer than 100 cases around the world. But there's no question people who suffer from hypertrichosis have been subjected to stigmas and public curiosity. Some have even been forced into working in circus sideshows.
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"Zombies" may be inspired by a fear of rabies
Rabies isn't a disease we think about much–unless you have an encounter with an erratic raccoon. But rabies might have something to do with the origin of our current zombie obsession. In their book Rabid: A Cultural History of the World’s Most Diabolical Virus, Monica Murphy and Bill Wasik write: "In their maddened lunges and infectious bites, our cinematic zombies…are nothing less than projections of our timeless fear of rabies."
Think about it: Rabies is transmitted through bites (from animals, of course, not un-dead humans), and rabies symptoms, especially once the disease has progressed, do sound zombie-esque—confusion, agitation, hyperactivity, and sometimes partial paralysis. Rabies can also lead to excess saliva production, which gives rabid animals the appearance of "foaming at the mouth." More than one movie zombie has been known to drool.
"Ghost sightings" may be hallucinations caused by a sleep disorder
In an interview with The Atlantic, Christopher French, a professor of psychology and head of the Anomalistic Psychology Research Unit at Goldsmiths, University of London, pointed out that sleep paralysis—a condition that affects up to 40% of people at some point in their lives—can lead to hallucinations that may be confused with paranormal experiences.
During an episode of sleep paralysis, you're somewhere between asleep and awake. Your brain is alert, but your body can't move. In this state, people tend to see things that aren't really there, and the hallucinations are oddly similar among sleep paralysis sufferers. "These hallucinations can be anything from feeling something on your skin, hearing something, seeing something, or feeling like someone is there in the room with you," Clete Kushida, MD, PhD, medical director of the Stanford Sleep Medicine Center told Health in a previous interview. Sounds a lot like a ghost visit to us!