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
Prohibited techniques often utilize "shirk", which is found in practices that prepare amulets or talismans. This is prohibited because "shirk" is the sin of practicing idolatry or polytheism i.e. the deification or worship of anyone or anything besides the singular God. Many times Qur'anic verses are added throughout the recitation when using these objects in order to 'mask' their "shirk". However, God believes he has provided sufficient cures in executing an exorcism, therefore exorcists should not have to rely on methods involving "shirk". Additionally, individuals seeking exorcism should avoid magicians or soothsayers because these magical practices go against Islamic Law.