BJPsych Advances (2019), vol. 25, 287–293 doi: 10.1192/bja.2019.12 Dissociative identity disorder: ARTICLE validity and use in the criminal justice system† Joel Paris the main cause of this disorder is severe childhood Joel Paris is Professor of Psychiatry SUMMARY abuse (Putnam 1989). It should be noted that this at McGill University, Montreal, Canada. He has been a member of This review examines whether the diagnosis of dis- diagnostic epidemic occurred at a time when profes- sociative identity disorder (DID) could be used to the Psychiatry Department at the sionals and members of the general public had support a defence of ‘not guilty by reason of insan- university since 1972, serving as serious concerns about unreported childhood abuse Department Chair from 1997 to 2007. ity’ (NGRI, or the insanity defence). The problem is and its putative sequelae. He is currently a research associate that DID has doubtful validity and can easily be mal- at the Jewish General Hospital (JGH) ingered. However, the diagnosis is listed in stand- Sibyl played an important role in popularising these in Montreal, and heads personality ard psychiatric manuals. If accepted as valid, DID ideas, both among clinicians and the general public. It disorder clinics at both the McGill would have problematic forensic implications. was a dramatic story, with villains and a heroine. We University Health Centre and JGH. He now know that the book was an almost complete fraud is a former Editor-in-Chief of the LEARNING OBJECTIVES Canadian Journal of Psychiatry. His (Rieber 2006). The name of the woman whom research interest is in borderline After reading this article you will be able to: Schreiber wrote about was Shirley Ardell Mason, personality disorder. • understand the history of the DID diagnosis and Nathan (2011) has published detailed research Correspondence Professor Joel • evaluate the validity of the DID diagnosis on her life. Mason had had years of treatment but Paris, Research Associate, SMBD- • appreciate, from case law, use of DID in support Jewish General Hospital, 4333 Côte had never previously presented with dissociative of an insanity defence. Ste Catherine Road, Montreal, symptoms. Her psychiatrist encouraged the explor- Quebec H3T 1E4, Canada. Email: joel. DECLARATION OF INTEREST ation of multiple personalities and insisted that [email protected] Mason must have been abused as a child. Yet Mason None. First received 7 Jan 2019 came from a reasonably normal family and had Final revision 22 Feb 2019 KEYWORDS never been abused. Transcripts of her therapy ses- Accepted 4 Mar 2019 Dissociative disorders; forensic psychiatry; sions clearly show that this narrative was imposed Copyright and usage insanity defence; comorbidity. on Mason, who may have been willing to go along © The Royal College of Psychiatrists with it because of her relationship with her therapist. 2019 † History of the DID diagnosis Dissociative identity disorder and its critics See commentaries, this issue. Janet (1924) coined the term ‘dissociation’, describ- The term ‘multiple personality disorder’ has been ing a state in which parts of the personality are sepa- replaced by ‘dissociative identity disorder’ (DID) in rated into inaccessible compartments. Prince (1906) DSM-5 (American Psychiatric Association 2013) popularised the concept by writing a book describ- and this is also the label used in ICD-10 (World ing a clinical case of multiple personalities, each of Health Organization 1992). Between 1970 and which seemed to have a separate existence. 1979 only 39 articles on MEDLINE concerned mul- Decades later, Thigpen & Cleckley (1954) described tiple personality or DID. Between 1980 and 1989 a very similar case, and the story was later turned the number of new articles cited was 212, rising to into a Hollywood movie, The Three Faces of Eve. 391 between 1990 and 1999. It has since levelled Yet while dissociative phenomena are dramatic, off, with 179 articles between 2000 and 2009, and the diagnosis was long considered to be a rarity. 197 between 2010 and 2018. The publication of another best-selling book (also DID has always had its critics. Many clinicians say made into a movie), Sibyl (Schreiber 1973), triggered they have never seen a case. Moreover, observers an epidemic of diagnoses of multiple personality in have been impressed by the sudden increase in the several countries, particularly the USA. Some identification of a once-uncommon disorder, and claimed that these cases are surprisingly common, most clinical and research reports came from a albeit undiagnosed, in clinical settings (Kluft 1985) small number of centres in the USA that specialise and that community prevalence could be as high as in dissociative disorders (McHugh 2008). These set- 1% (Ross 1991). Moreover, it has been claimed that tings offer extended and costly in-patient treatment 287 Downloaded from https://www.cambridge.org/core. 30 Sep 2021 at 20:09:13, subject to the Cambridge Core terms of use. Paris to reintegrate the various ‘alters’ into which person- was any solid evidence of childhood abuse (Nathan ality has putatively fragmented (Putnam 1989). 2011). The effects of therapist suggestion on produ- However, the diagnosis of DID often leads to a cing false memories has been documented in the lit- series of ‘therapeutic’ procedures that exaggerated erature (Moritz 2015; Rozental 2016). This is the very symptoms that characterise the syndrome especially the case for dissociative symptoms (Piper 2004a, 2004b). (Merckelbach 2017). The use of hypnosis in treatment, and the false DID as an artefact of therapy memories it can create, is a particularly worrying element. Hypnotic trance is, at least in some ways, Critics of the DID diagnosis have argued that the a form of socially determined role-play (Spanos most parsimonious explanation for the phenomena 1996; Lilienfeld 1999). The clinical features of DID associated with DID is that they develop in patients may therefore depend on role-playing, so that who are suggestible, fantasy-prone and willing to patients provide memories of trauma on demand. play a role, and who are treated by therapists who Moreover, the number of ‘alters’ has a troubling ten- are convinced about the reality and ubiquity of this dency to increase over time, most likely due to a wish diagnosis (Lilienfeld 2007). Thus, the clinical to keep therapists interested (Piper 2004a). But picture that emerges depends on a folie à deux while most clinicians never make a DID diagnosis between therapist and patient. This is what Spanos and do not seriously believe in it, a small group of (1996) referred to as ‘role-playing’, both in hypnotic supporters have kept the idea alive. states and in therapy. This is not to deny the reality of dissociation as a symptom. Research shows that the capacity for dis- Memory wars sociation is determined not only by the environment, The concept of repressed and recovered memories but is a trait that is partially heritable (Jang 1998). has been challenged over and over again. One of This suggests that dissociative symptoms would be its leading critics has been Elizabeth Loftus, whose better understood using an interactive stress–diath- research showed how easy it is to implant a false esis model, in which adverse experiences amplify memory (Loftus 1994). One of the most significant temperamental vulnerabilities. critics today is Harvard’s Richard McNally (2003, But the creation of dissociative disorders by 2012). McNally has conducted extensive research means of psychotherapy is a different phenomenon. showing that people with recovered memories Some patients are highly vulnerable to suggestion score high on fantasy proneness and exhibit a ten- from therapists, and DID is most likely an artefact dency to develop memory illusions. of specific techniques. Thus, therapists may insist False memories are based on these mechanisms, that patients must have been abused during child- and not on repression of trauma. The key observation hood. Moreover, dissociative symptoms receive is that false memories of childhood trauma are entirely strong reinforcement. This scenario creates the unlike post-traumatic stress disorder, in which painful drama of the disorder. As a result, DID is only memories are not forgotten but return to conscious common in treatment settings that encourage and thought all too frequently. McNally’scolleague reward these symptoms (McHugh 2008). Susan Clancy (2005) has shown that the same mechanisms drive false memories of alien abduction. The malleability of memory Unfortunately, the controversy is not over. While The therapeutic methods developed for the evaluation mainstream psychology is clear that repression and and treatment of dissociative disorders are based on recovered memory are dubious concepts, many an incorrect theory of human memory (McNally countries have small groups of clinicians who 2003, 2012). Memories of the past are rarely factually promote these ideas. The vast majority of DID sup- accurate, but tell old stories in new ways, recreating porters are clinicians who have never conducted any and reinterpreting the past in light of the present. research. But they have found support from those Few can recall childhood experiences with accuracy, who dissent from received opinion. For example, and hardly anyone can remember events before the an article supporting the validity of recovered age of 3. And it is not difficult to convince some memory was published in the prestigious journal patients that they have repressed memories of child- Psychological Bulletin (Dalenberg 2012). This pub- hood abuse (Loftus 1994;Pope1995). lication was quickly followed by a rebuttal, written Thus, the memories of patients diagnosed with by leading experts in memory, refuting its argu- DID are narratives, but need to be supported by ments one by one (Lynn 2012). Another supporter other narratives. For example, Sibyl’s therapist did from the mainstream linked to the dissociation and not take the trouble to find out what other family trauma movement is the British psychologist Chris members thought of her story, or whether there Brewin (2012), who continues to insist that those 288 BJPsych Advances (2019), vol.