Exorcism
In Catholic Christianity, exorcisms are performed in the name of Jesus Christ. A distinction is made between a formal exorcism, which can only be conducted by a priest during a baptism or with the permission of a bishop, and "prayers of deliverance" which can be said by anyone.
The Catholic rite for a formal exorcism, called a "Major Exorcism", is given in Section 11 of the Rituale Romanum. The Ritual lists guidelines for conducting an exorcism, and for determining when a formal exorcism is required. Priests are instructed to carefully determine that the nature of the affliction is not actually a psychological or physical illness before proceeding.
The Exorcism of Emily Rose
During the trial, Emily's past is told through flashbacks and the evidence provided by witnesses. Presiding over the trial is Judge Brewster, with Ethan Thomas, a practicing Methodist, serving as prosecutor. The prosecution claims Emily suffered from epilepsy and psychosis to explain her behavior. Emily received a scholarship to study for a bachelor's degree but displayed signs of demonic possession after she began attending classes, experiencing visions and physical contortions. Diagnosed with epilepsy, Emily received anti-seizure medication but the treatment failed to cure her. A friend named Jason took Emily back home to her family, where she continued displaying traits of possession until Moore was summoned to attempt an exorcism.