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.
Others explain the increase as being due to the use of inappropriate therapeutic techniques in highly suggestible individuals, though this is itself controversial while proponents of DID claim the increase in incidence is due to increased recognition of and ability to recognize the disorder. Figures from psychiatric populations (inpatients and outpatients) show a wide diversity from different countries.A 1996 essay suggested three possible causes for the sudden increase of DID diagnoses, among which the author suspects the first being most likely:
The result of therapist suggestions to suggestible people, much as Charcots hysterics acted in accordance with his expectations. Psychiatrists past failure to recognize dissociation being redressed by new training and knowledge. Dissociative phenomena are actually increasing, but this increase only represents a new form of an old and protean entity: "hysteria".Dissociative disorders were excluded from the Epidemiological Catchment Area Project. North America
DID is considered a controversial diagnosis and condition, with much of the literature on DID still being generated and published in North America, to the extent that it was once regarded as a phenomenon confined to that continent though research has appeared discussing the appearance of DID in other countries and cultures. Although the condition has been described in non-English speaking nations and non-Western cultures, these reports all occur in English-language journals authored by international researchers who cite Western scientific literature and are therefore not isolated from Western influences.