With there being no scientific evidence for demons, there are no studies on the effectiveness of Holy Water or repeated exhortations to get rid of them. While it’s unclear if any demons have been cast out, we do know persons have died in these attempts, from asphyxiation, poisoning, and blunt force trauma.

Though primarily associated with the Catholic Church, exorcisms are also endorsed by Orthodox and protestant denominations. It is also a feature of some sects of Hinduism and Islam. But it’s almost invariably Catholic priests and bishops who are featured in movies or paintings since they sport cool tunics, staffs, and giant cross necklaces when sending dark lords scurrying.

Most documented cases involve only the testimony of the possessed, the exorcist, and maybe a couple of family members. Sometimes even those names are kept secret. This makes the cases impossible to investigate, but the descriptions seem best explained by the likes of epilepsy, schizophrenia, or trickery. The subject can be willing, reluctant, or forced. Some genuinely believe it. If this belief is owed to subjective validation and communal reinforcement, these same phenomenons can convince the person they are cleansed once the exorcism is complete. If the underlying reason is physical or mental, the symptoms continue, with demons continuing to take the blame.

Those said to be afflicted by demons act like how possessed persons are depicted in film and literature: Flailing, harming one’s self and others, and communicating in a deep, tortured voice. The demons always speak whatever language the possessed does, as opposed to the more logical Hebrew.

In Matthew, Jesus cast out demons into herd of swine, which promptly made a beeline off a cliff. Why the afflicted person hadn’t hurled himself over the cliff first is unclear. Nor does the Bible explain why Jesus didn’t just cast the demons directly into Hell instead of giving them a pig layover. Some think since Jesus cast out demons, they can, too, even though they don’t think they can also walk on water or heal the blind. Then again, with demon casting, there’s no way you can be disproven.

In the Middle Ages, possession was used to explain almost any illness or abnormality. It was even said to be responsible for alcoholism, prostitution, and sloth. Reports of possessions in these times usually included convulsions, immense strength, numbness to pain, temporary blindness or deafness, and clairvoyance. These may have been manifestations of epilepsy, migraines, schizophrenia, Tourette’s Syndrome, or other disorders. As science began to understand mental illness and physiology, demons as an explanation become less necessary. Today, medicine and psychology consider a “diagnosis” of demon possession to be a mislabeling of other conditions. I found one online list of demon possession signs that merely mirrored indicators of being suicidal.

As much as it ever would, the Catholic Church admits all this is its official stance on exorcism, which reads, “Before an exorcism is performed, it is important to ascertain that one is dealing with the presence of the Evil One, and not an illness.” Even if no illness is detected, it is a non sequitur to think chasing demons will do any good.

Christianity still holds onto it, however, as a way of maintaining relevance. If you need an exorcism, only the church can provide one. Some have entered the modern age. Bob Larson conducts exorcisms by phone and some televangelists encourage afflicted persons to lay their hands on the TV and let the sanctifying force come bursting through. There may even be exorcism via Facebook texts these days, I don’t know.

Sometimes, the only thing the victim is possessed with is a sense of humor. Trickery was behind two of the 19th Century’s most storied possession tales, those of the Fox sisters and Davenport brothers. Both revealed the ruse in old age. Other times, skeptics have been the ones to uncover the deception. When cases have been properly investigated by illusionists and detectives using hidden cameras and tracer powders, the possessions are shown to be pranks.

The descriptions of what happens during an exorcism are wide-ranging, tangential, and noncommittal. Here’s one example: “Anything or nothing can happen. There is no set standard. In some cases, all hell seems to break loose. In others, not a peep is heard. It can take some time before you are sure an exorcism has worked. Sometimes the ritual forces the demons into a state of dormancy. However, the problem may arise again.”

There is no consensus on why a demon would enter a person or what they gain by it. There are several lists of discouraged behaviors that could leave one’s self open to possession. Some of these contain virtually every action known to mankind. Here is a more specific list I found, and I’ll peruse it for how at-risk I am:

1. Going to churches whose members bathe in the river. My Unitarian church is within a mile of the Mississippi River, which is a really lousy place to try and get clean. Besides, I only shower.

2. Eating food sanctified to idols. I’ve been a vegetarian for 21 years and never heard of anyone sacrificing an eggplant.

3. Reading occult books and literature. Think I’m in moderate danger here. My home library includes Dracula, Frankenstein, Dr. Jekyll & Mr. Hyde, and Pride & Prejudice. I know that last one doesn’t quite fit, but Elizabeth Bennet sometimes alludes to feelings of sensuality, and arousal is another no-no.

4. Adultery, or having premarital sex with a possessed person. The latter presumably cancels itself if both partners are possessed. As to the former, if I did this, a demon would be the least of my concerns.

5. Consulting witch doctors or mediums. My health care plan doesn’t cover these, so I’m good to go.

6. Reading or watching porn. I may have left myself vulnerable here. The other day, I viewed asexually reproducing amoebas on Animal Planet.

7. Watching horror movies. Oh dear, watch out. A frothy mix of blood and vomit is about to come spewing through your monitor.