By Emilia Wisniewski (COM’25) and Katrina Scalise (COM’25)

In the new movie “The Exorcist: Believer,” a sequel to the 1973 horror classic, a father seeks to save two demonically-possessed girls through the ancient rite of demonic exorcism. The film is the latest installment in our demonic-obsessed culture, where a powerful, malevolent supernatural or paranormal entity causes people to display strange, frightening, or violent behavior.

Belief in demons goes back centuries, likely emanating from people’s fear of the unknown, of individuals who displayed behavior deemed to be strange or different. In fact, during the Middle Ages, when demons bedeviled communities, shocked religious leaders, and puzzled doctors, the concepts of “demonic possession” or “demonic obsession” were often an explanation for mental illness, says Associate Professor of Religion and History Deeana C. Klepper.

“Most of us know about possession of humans by demons from pop culture, but medieval authors didn’t only use the term ‘possession,’ they also used the term ‘obsession,’ which is to be tortured or tormented or harmed in some way without the demon taking over the person’s being,” Klepper says.

Through the 13th century, Klepper says, behaviors we might associate with mental illness were often thought to be caused by “demonic possession” — a demon taking full possession of a person’s body without their consent. But by the later 14th century, people began to avoid religious explanations for mental illnesses; instead, they spoke in medical terms about imbalances of the four humors in the human body as the cause of mental illness.

Those who did still see a spiritual source to such suffering began to speak in terms of “demonic obsession,” an attack from the outside that would cause sudden, irrational behavior or self-harm, Klepper says. An external demonic obsession might have allowed for “a more compassionate response to the mentally ill… as there was a clearer distinction between human and demon” and therefore “ less fear of the demon’s lingering presence,” Klepper says.

In fact, Klepper says, one priest, Augustinian canon Albert from Bavaria, suggested in a 1370s Latin manual for German parish priests that those who “take their own life in the throes of that experience of demonic harassment” — demonic obsession — deserved to be buried with their loved ones, even though that was usually forbidden. This was a more compassionate view about people’s mental health than others in the region, Klepper says. During the same time period, some European city governments banished people who exhibited signs of mental illness.

“He’s really doing something incredibly meaningful for the community and finding a way to work around certain restrictions that don’t feel very humane, that feel really problematic,” says Klepper, whose second book, Pastoral Care and Community in Late Medieval Germany: Albert of Diessen’s Mirror of Priests, focused on the writings of Albert from Bavaria.

For the last few years, Klepper has been researching how to reconcile these two opposing realities: harsh banishments due to demonic posession versus increased sympathy for those who suffered from demonic obsession.

To research this, Klepper traveled to Bologna, Italy in 2022. She searched libraries at the city’s university, which houses one of the oldest medical schools and one of the most prominent law schools that teaches Christian Canon Law and secular law, for records of demonic obsession. When she found nothing, she headed to Germany to see if there were any relevant manuscripts there, and she has also searched at the Huntington Library in California and the Bodleian Library in Oxford.

Two years into her research project, the next step for Klepper is to spend more time looking at vernacular texts and advice manuals for priests for additional mentions of demons. Eventually, she hopes to write a book for both an academic and general audience on demonic obsession and mental illness and its perception through history.

This book would explicitly make connections between this medieval phenomenon—and its fear-compassion spectrum—and trace it into the modern, making connections with our own world, Klepper says.

“While thinking about mental illness as an attack by demons might seem silly to the scientifically minded among us, we clearly still operate out of a sense of fear of those who exhibit confusing, agitated, unusual behaviors,” she says. “I think that by taking a long look and using the evocative model of demonic obsession and response, we might be able to explore our own fears of and prejudices toward people suffering from mental illness, for whom we should have compassion.”