Evidence against the iatrogenesis of multiple personality disorder.

The authors present data which argue against the iatrogenesis of multiplepersonality disorder (MPD). Twenty-two cases reported lJy one Canadianpsychiatrist, 23 cases reported lJy a second Canadian psychiatrist, 48 cases seen lJy 44 Americanpsychiatrists specializing in MPD, and 44 cases seen lJy 40 Canadian general psychiatrists without a special interest in MPD are compared. The Canadian generalpsychiatrists hadseen an averageof2.2 cases ofMPD, while theAmericanshadseen anaverageof16. O. There were no differences between these groups on the diagnostic criteria for MPD or the number of personalities identified. Specialists in MPD are not influencingtheirpatients to create an increased numberofperson­ alities or to endorse more diagnostic criteria. Exposure to hypnosis does not appear to influence the phenomenology ofMPD. Since the nineteenth century (Binet, 1896; Ellenberger, 1970), there have been suspicions that multiple personality disorder (MPD) is the iatrogenic product ofthe relationship between a suggestible patient and a misguided therapist. Binet (1890, 1896) and others demonstrated the artificial production of dissociated states in the nineteenth century. In the 1940s a review article (Taylor & Martin, 1944) dealt with iatrogenesis and a series of papers (Harriman, 1942a; Harriman, 1942b; Harriman, 1943; Leavitt, 1947) demon­ strated that analogs of some of the features of MPD can be induced experimentally in normal highly-hypnotic volun­ teers. Recent work has confirmed these findings with more rigorous experiments (Kampman, 1976; Spanos, Weekes & Bertand 1985; Spanos, Weekes, Menary & Bertrand, 1987). The belief that MPD is an iatrogenic artifact has no support from the study ofactual MPD patients, however. On the other hand, there are no data from a large series ofMPD cases which argue against iatrogenesis. To date the best argument against the iatrogenesis of MPD is based on extensive clinical experience (Braun, 1984; KIuft, 1982; KIuft, 1987). In the context ofthis controversy, we collected 236 cases of MPD reported to us by 203 clinicians throughout North America, who had jointly seen 1807 cases (Ross, Norton & Wozney, 1989). The 236 cases included 44 cases seen by 40 general Canadian psychiatrists, and 48 cases seen by 44 American psychiatrists specializing in MPD who are mem­ bers of the International Society for the Study of Multiple Personality and Dissociation (ISSMP&D). The remainder of the 236 cases were reported by psychologists and other non­ medical therapists. In addition we gathered data on 22 cases ofMPD seen by one Canadian psychiatrist, and 23 cases seen by a second Canadian psychiatrist, both of whom are members of ISSMP&D. We thought it would be instructive to study single caseloads of two Canadian specialists in MPD, to determine' whether their patients differ from cases seen by generalist colleagues. We compared the four groups of MPD cases to deter­ mine their differences and similarities. We hypothesized that if MPD is due to iatrogenesis, then specialists in MPD ought to exert this influence more strongly than general psychiatrists. If MPD is due to iatrogenesis, the following should be observed: