Exorcism is the religious or spiritual practice of purportedly evicting demons or other spiritual entities from a person or an area they are believed to have possessed. Depending on the spiritual beliefs of the exorcist, this may be done by causing the entity to swear an oath, performing an elaborate ritual, or simply by commanding it to depart in the name of a higher power. The practice is ancient and part of the belief system of many cultures and religions. Requested and performed exorcisms had begun to decline in the United States by the 18th century and occurred rarely until the latter half of the 20th century when the public saw a sharp rise due to the media attention exorcisms were getting. There was “a 50% increase in the number of exorcisms performed between the early 1960s and the mid-1970s”
Those who profess a belief in demonic possession have sometimes ascribed to possession the symptoms associated with physical or mental illnesses, such as hysteria, mania, psychosis, Tourette's syndrome, epilepsy, schizophrenia or dissociative identity disorder. Additionally, there is a form of monomania called demonomania or demonopathy in which the patient believes that he or she is possessed by one or more demons. The illusion that exorcism works on people experiencing symptoms of possession is attributed by some to placebo effect and the power of suggestion. Some cases suggest that supposedly possessed persons are actually narcissists or are suffering from low self-esteem and act demonically possessed in order to gain attention. Within the scientific community, the work of psychiatrist M. Scott Peck, a believer in exorcism, generated significant debate and derision. Much was made of his association with (and admiration for) the controversial Malachi Martin, a Roman Catholic priest and a former Jesuit, despite the fact that Peck consistently called Martin a liar and manipulator. Other criticisms leveled against Peck included claims that he had transgressed the boundaries of professional ethics by attempting to persuade his patients to accept Christianity.