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.
Exorcism of Roland Doe
In the late 1940s, in the United States, priests of the Roman Catholic Church performed a series of exorcisms on an anonymous boy, documented under the pseudonym "Roland Doe" or "Robbie Mannheim". The 14-year-old boy (born circa 1935), was the alleged victim of demonic possession, and the events were recorded by the attending priest, Raymond Bishop. Subsequent supernatural claims surrounding the events were used as elements in the 1971 novel "The Exorcist" by William Peter Blatty and the 1973 film adaptation.