Once a rarely occurring spontaneous phenomenon (research in 1944 showed only 76 cases), the diagnosis became "an artifact of bad (or naïve) psychotherapy" as patients capable of dissociating were accidentally encouraged to express their symptoms by "overly fascinated" therapists.In a 1986 book chapter (later reprinted in another volume), philosopher of science Ian Hacking focused on multiple personality disorder as an example of "making up people" through the untoward effects on individuals of the "dynamic nominalism" in medicine and psychiatry. With the invention of new terms entire new categories of "natural kinds" of people are assumed to be created, and those thus diagnosed respond by re-creating their identity in light of the new cultural, medical, scientific, political and moral expectations. Hacking argued that the process of "making up people" is historically contingent, hence it is not surprising to find the rise, fall, and resurrection of such categories over time. Hacking revisited his concept of "making up people" in a 2006. "Interpersonality amnesia" was removed as a diagnostic feature from the DSM III in 1987, which may have contributed to the increasing frequency of the diagnosis. There were 200 reported cases of DID as of 1980, and 20,000 from 1980 to 1990. Joan Acocella reports that 40,000 cases were diagnosed from 1985 to 1995. Scientific publications regarding DID peaked in the mid-1990s then rapidly declined.There were several contributing factors to the rapid decline of reports of multiple personality disorder/dissociative identity disorder.
Reviews of medical records and psychological tests indicated that the majority of DID patients could be diagnosed with BPD instead, though about a third could not, suggesting that DID does exist but may be over-diagnosed. Both groups also report higher rates of physical and sexual abuse than the general population, and patients with BPD also score highly on measures of dissociation. Even using strict diagnostic criteria, it can be difficult to distinguish between dissociative disorders and BPD (as well as bipolar disorder and schizophrenia), though the presence of comorbid anxiety disorders may help.}} Causes
General
DID is etiologically complex. Şar et al. state, "Dissociative identity disorder (DID) is multifactorial in its etiology. Whereas psychosocial etiologies of DID include developmental traumatization and sociocognitive sequelae, biological factors include trauma-generated neurobiological responses. Biologically derived traits and epigenetic mechanisms are also likely to be at play. At this point, no direct examination of genetics has occurred in DID. However, it is likely to exist, given the genetic link to dissociation in general and in relation to childhood adversity in particular." Stating that there is "a lack of understanding regarding the etiopathology of DID", Blihar adds that "many researchers and psychiatrists regard DID as the most severe form of a childhood onset post-traumatic stress disorder (PTSD) because it is virtually impossible to find a DID patient without a history of PTSD. ... There are currently two competing theories regarding the relationship between trauma and dissociation: the trauma-related model and the fantasy-prone model.