In examining the historical and anthropological background of such practices, accounts of religions, cults, and fraternal organizations were found to have used traumatic rituals to create altered states of consciousness. Apparently, such mental states have sometimes been viewed as sacred, i.e., as the magical catalyst for profound visions or possession by gods. In other cases, these techniques have allegedly been used to establish psychological control, which has existed largely in secrecy, essentially unknown in the mental health professions. Based on patient accounts, however, these traumatic acts of mind control occur in modern, civilized societies, including contemporary America. The stories told by patients include descriptions of abuse in sadistic ceremonies, some of which are allegedly associated with satanic, luciferian, and other ideologies alien to mainstream values. The psychiatric symptoms displayed by these individuals are similar to those described as "possessed" in various other cultures. The authors conclude that the diagnosis of multiple personality disorder, or as it has been renamed, dissociative identity disorder, is a Western version of what has been known historically and anthropologically as possession. The authors discuss the controversy over the validity of ritual abuse claims by the patients of mental health professionals and the willingness of some therapists to believe these claims. The controversy is fed by the politics of psychotherapy, a generally unsympathetic and sometimes hostile media bias, and a growing contingent of individuals who argue that current allegations of child abuse are overstated. Appendixes contain a proposed diagnosis for cult and ritual trauma disorder and a profile of the Society for the Investigation, Treatment, and Prevention of Ritual and Cult Abuse. 506 references and a subject index