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 in Islam
Possession is not caused by Satan, who is said to be just a tempter, whispering evil suggestions into humans heart, but, even though not mentioned in canonical scriptures, according to folklore by jinn, who can enter a human body physically or haunting them mentally. A possession by a jinn can happen for various reasons. Ibn Taymiyyah explained a Jinn could sometimes haunt an individual, because the person could (even unintentionally) harm the jinn; urinating or throwing hot water on it, or even killing a related jinn without even realizing it. In this case the jinn will try to take revenge on the person. Another cause for jinn possession is when a jinn falls in love with a human and thereupon the jinn possesses the human. Some women have told of their experiences with jinn possession; where the jinn tried to have sexual interaction from inside their bodies. Thirdly, it occurs when a jinn is evil and simply wants to harm a human for no specific reason, it will possess that person, if it gets the opportunity, while the human is in a very emotional state or unconsciousness. Jinn may also haunt someone in service of a sorcerer.