The Very Human Science Behind Demonic Possession

Though demonic possession has been explained by science and medicine, there's still a widespread popular belief in possessions and exorcisms. In fact, a 2003 Yougov poll of 1,000 Americans found that most believe in the existence of the devil - and just under half believe in the power of exorcism. Granted, they don't think that these happen very often, but they definitely still believe that it works. Maybe it's the power of films like The Exorcist and The Exorcism of Emily Rose, maybe it's just plain old fascination with the demonic, but a lot of people chose to believe in religion over science when it comes to the apparently supernatural. 

But this misunderstanding about what causes people to appear possessed can do a lot of damage. Exorcisms are still performed with surprising regularity, often ignoring real mental and physical health issues. And even in this day and age, exorcisms gone wrong can still result in death. In so many instances, there are clearly underlying issues that cause the symptoms of possession, and the very real science is ignored in the face of religious or spiritual beliefs.

Read on for some real explanations for demonic possession, from epilepsy to accidental trips.

  • Ergot Poisoning

    Ergot Poisoning
    Photo: Unknown / Wikimedia Commons / Public Domain

    The Salem witch trials began in 1692 and resulted in over 150 accusations of witchcraft. Many of the young women accused displayed intense contortions, outbursts, hallucinations, and spasms. The frenzied accusations and confessions - as well as the subsequent execution of the accused "witches" - are now a source of embarrassment and have often been described as mass hysteria or religious fervor.

    But there may be another explanation. Linnda Caporael, a behavioral psychologist studying the trials in the 1970s, saw many of the symptoms of ergotism, or ergot poisoning. Ergot (from which LSD is derived) is a fungus which can affect rye grain - the major grain in Salem at the time. The symptoms of ergotism? Vomiting, delusions, hallucinations, and muscle spasms, just to name a few.

  • Epilepsy

    The Exorcism of Emily Rose may be one of the most famous onscreen portrayals of demonic possession, but it had real-life roots in the tragic story of Anneliese Michel. Her "demonic possessions" consisted of shouting obscenities, self-mutilation, and displays of aggression. She refused food for an extended period, weighing only 68 pounds at the time of her death.

    The two priests who held dozens of exorcisms on Michel were eventually convicted of negligent homicide and the prosecution pointed to clear scientific reasons behind her death. She had a history of depression and was diagnosed with epilepsy, but in the months leading up to her passing, she was not receiving medical treatment. At the trial, doctors said that she had died of a combination of mental illness and epilepsy in an intensely religious environment. Professor Hans Sattes of Wuerzburg University claimed these combined to "a spiritual sickness and heavy psychic disturbance."

  • Dermographism Urticaria

    It's a big Latin phrase that just translates into "writing on the skin" and it may explain one of the physical symptoms of demonic possession. In the case of Roland Doe, the real-life inspiration for The Exorcist, there were red marks found on his body described as looking "like lipstick." 

    There's a chance that raised red marks like these are actually done by the person themselves, even without them knowing. Dr. Kathleen Sands explained in a lecture called "Demonic Possession and Exorcism: Medical Explanations?" at the College of Physicians of Philadelphia that dermographism urticaria is a condition where someone traces or presses their skin so much it can create red lines or welts, even forming words. Of course, it would be pretty confusing (and spooky) if you didn't know the person suffered from the condition.  

  • Schizophrenia

    Photo: Philippe Alès / Wikimedia Commons / CC BY-SA 3.0

    One of the most recent cases of exorcism in the news was in 2005 - the exorcism of Romanian nun Maricica Irina Cornici, which sadly resulted in her death. After saying the devil was speaking to her, she was tied to a cross and gagged to stop her making any sounds before being left without food and water for three days. Her aunt said she "was disfigured, she had marks on her hands, her ankles and her stomach." 

    But Cornici had previously been diagnosed with schizophrenia, a condition that has historically been confused with possession. Unfortunately, the priest who ran the exorcism didn't agree with the diagnosis. "God has performed a miracle for her, finally Irina is delivered from evil," he said after her death. 

  • Tourette Syndrome

    There are many cultures where Tourette syndrome has been misunderstood as demonic or supernatural, and some of the most famous examples of demonic possession may have actually included an element of Tourette. The Exorcist is based on the true story of a boy who was documented under the pseudonym Roland Doe. 

    While some elements of the film (like objects flying around the room and a head spinning all the way around) may be beyond scientific reach, some of the more realistic behaviors are straight out of the textbook. Psychiatrist Arthur K. Shapiro and psychologist Elaine Shapiro of Cornell University believed that the grunting, jerks, and profanities of the child that inspired The Exorcist could all be explained by Tourette's

    Chris French, professor of psychology at Goldsmiths, says that this is a long-standing confusion: "Interestingly, the first recorded description of a case of Tourette’s may be in Malleus Maleficarum (or Witch’s Hammer) published in the 15th century by Jakob Sprenger and Heinrich Kraemer. This notorious book served as a guide for identifying witches and the possessed and included a description of a priest whose tics were thought to be a result of possession by the devil."

  • Allotriophagy

    Photo: Anonymous / Wikimedia Commons / Public Domain

    There were lots of cases of demonic possession in early modern Europe with a range of symptoms. One of the weirdest - and most difficult to explain - symptoms is vomiting up things that should not have been in the body in the first place. Brian Levack, t professor of history at the University of Texas, Austin, explains that people "would vomit alien objects like nails and pins and stones." 

    It sounds devilish, but is it? Dr. Kathleen Sands explained in a lecture at the College of Physicians of Philadelphia that allotriophagy (the desire to eat things that are definitely not food) could be the explanation for this apparent sign of possession.