The belief that demons exist and can possess people is of course the stuff of fiction and horror films — but it is also one of the most widely-held religious beliefs in the world. Most religions claim that humans can be possessed by demonic spirits (the Bible, for example, recounts six instances of Jesus casting out demons), and offer exorcisms to remedy this threat.
The idea that invading spirits are inherently evil is largely a Judeo-Christian concept; many religions and belief systems accept possession by both beneficent and malevolent entities for short periods of time as uncommon — and not especially alarming — aspects of spiritual life. Spiritualism, a religion that flourished across America in the 1800s and is still practiced in a few places today, teaches that death is an illusion and that spirits can possess humans. New Agers have also long embraced a form of possession called channeling, in which spirits of the dead are said to inhabit a medium’s body and communicate through them. Hundreds of books, and even some symphonies, have been allegedly composed by spirits.
Hollywood, of course, has been eager to capitalize on the public’s continued fascination with exorcism and demonic possession with films often dubbed “based on a true story.” There are countless exorcism-inspired films, including “The Last Exorcism,””The Devil Inside” and ” — wildly varying in quality, originality, and scariness. The greatest cultural influence, of course, came from the classic “The Exorcist.” In the weeks after the film came out in 1974, a Boston Catholic center received daily requests for exorcisms. The script was written by William Peter Blatty, adapted from his best-selling 1971 novel of the same name. Blatty described the inspiration for the film as a Washington Post article he’d read in 1949 about a Maryland boy who had been exorcised. Blatty believed (or claimed to believe) it was an accurate account, though later research revealed the story had been sensationalized was far from credible.