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.
Minor exorcism in Christianity
In addition to these exorcisms, the Rite for Adults includes three ceremonies called scrutinies, to be celebrated as integral parts of the Sunday Eucharist on the Third, Fourth, and Fifth Sundays of Lent. Each scrutiny contain a prayer of exorcism reserved to the deacon or priest. There is also a simplified set of prayers provided for use with children mature enough to be personally catechised. The only minor exorcism in the children's rite is part of a one-off scrutiny which is offered in two forms. Both texts use the image of entering the light of Christ, turning respectively from "darkness" and from "whatever could make them bad".