A passage out of an Italian exorcism book from 1576, “Compendio Dell’arte Essorcistica,” which details stopping the operations of demons and evil spirits.

No film will ever be as frightening or disturbing as “The Exorcist,” in which two Catholic priests rid a girl of the demon possessing her through a process called an exorcism. To investigate the truth behind exorcisms, Student Life spoke with several members of the Catholic Church, all of whom preferred to remain anonymous. Here are their explanations of the rite and the challenges it presents.

While describing someone as possessed often conjures up images of men dancing like marionettes or being manipulated by the devil, the actual belief is far more subtle. “[Demons] don’t have the ability to do things only God can do, like take away our free will or even our intellectual capacity. They’re more like a mad scientist who can modify matter; at some point down the road we might have that scientific knowledge, too,” one clergyman said. “In certain cases, the devil, for whatever reason, usually through sin, becomes completely occupied by some images suggested through that spirit. The person has freedom, but it’s not being expressed. There’s a sort of weakness of will, and some degree of collaboration as well.”

Nonetheless, interaction of any sort with demons can be terrifying. One priest spoke about spiritual warfare, the belief that demons are constantly battling for influence over human souls. The term comes from the Bible, in which the writer urges Christians “to stand firm against the schemes of the devil.” The priest gave other examples. “In the history of the lives of the saints, there are harassment stories, which is a deeper level of spiritual warfare. It’s all forms of temptation for greater power though.” The priest cited the temptation of Jesus as another example. He noted, however, that more recent possessions normally result from “risky” interests. “There’s a real slippery slope called the occult, in which people give into the temptation for greater power. There’s a metaphor that you ‘sell your soul to the devil’ and I guess that’s appropriate. They choose this power willfully, since there’s a temptation to do anything for that power.”

Of course, the definition of possession is now far stricter. Symptoms now attributed to mental illness were formerly signs of possession. The church is far more careful now in diagnosing possession. “Discernment is the term used in the church. Similar to the way a doctor develops a diagnosis, a team looks for signs of possession. The bishop’s office is somehow involved, and many times a bishop is involved,” the priest said.

The two strongest indicators are preternatural knowledge and aversion to blessed objects. For example, if the patient knows personal details about the priests present without ever meeting them, the patient has exhibited preternatural knowledge. If the patient responds strongly and negatively to a hidden object in the room, like holy water or a rosary, the patient may be possessed. “Manifestations can be disturbing,” the priest said. “There are two extremes: attributing everything to demonic activity or nothing at all. You can get out of balance easily, being occupied with it or ignoring it completely.”

Priests also take a “medical history” of the patient, and ask if the patient has recently dabbled in the occult. “‘Have you been going to fortune tellers or other occult practices,’ that sort of thing,” he said.

The exorcism itself requires a lot of preparation from the priest. While some rites in the Catholic Church, like baptism, are guaranteed to work if performed properly, exorcism is more like a prayer. Its effectiveness depends heavily on the faith of the priest. “An exorcism is ‘ex opera operantis,’ which means “from the action of the doer,” the priest said. The exorcist normally attends confession beforehand, and prays much before the rite.

The rite then takes place. The priest follows the rite, which includes readings from the Bible and several invocations of God’s power. Some of the prayers involve impressive diction, like “I adjure you, serpent of old, cursed dog, by the judge of the living and the dead.” Critically, the exorcist must remain humble. “It’s important to remember that the exorcist doesn’t expel the demon, but God does,” the clergyman explained.

The follow up procedures differ depending on the case. “It varies. Some sessions take just once, and it’s done. The famous one here in St. Louis took months. It depends on the severity of the wounds and the depth of the invasion. An exorcism is like a major surgery if there’re some real emotional sounds there as well.” Yet the exorcism itself is a product of God’s power; the priest admitted the impossibility of understanding it all, “There’s a lot of mystery to it as well,” he said.

Also see: The famous exorcism in St. Louis