An exorcism in 2005 at a convent in the Romanian town of Tanacu resulted in the death of Maricica Irina Cornici, a 23-year-old nun who said she heard the devil telling her she was sinful. With assistance from four nuns, priest Daniel Corogeanu bound Cornici to a cross, gagged her mouth with a towel, and left her for three days without food or water. The ritual was an effort to drive devils out of the woman. Cornici, who had a history of schizophrenia, died of suffocation and dehydration.
The Vatican (which as of last year offered courses on exorcisms) accepts only a small percentage of demonic possessions as "authentic," which of course suggests that there are a lot of unauthentic cases of possession out there. The Vatican issued official guidelines on exorcism in 1614 and revised them in 1999. Along with a handful of Vatican-sanctioned exorcists, hundreds of self-styled exorcists roam America and the world supposedly helping people cleanse themselves.
Author Michael Cuneo, who participated in more than 50 exorcisms while researching his book American Exorcism: Expelling Demons in the Land of Plenty (2002, Broadway Books) found no reason to think that anything supernatural occurs during exorcisms. While many Americans likely think of exorcisms as relics of the Dark Ages, exorcisms continue to be performed, often on (and by) people who are emotionally and mentally disturbed.