In this article we will analyse the tradition «La endemoniada», by Ricardo Palma, which tells the story of demonic possession and the consequences of exorcising Ursulita. It also reveals the lack of ethics and morals on the part of Fray Gil, who supposedly exorcised her. Based on this tradition, our research will focus on the psychological disorder called schizophrenia. Since the 16th century, this disorder has generated confusion among people, as religion has demonised it, while science has sought various treatments for its cure. Finally, we will review the case of Vilma Trujillo, who was burned in an alleged act of exorcization.