The popular media has offered such examples as "Eve" (based on Chris Costner-Sizemore) and "Sybil" (based on Shirley Ardell Mason) as sufferers of dissociative identity disorder (at one point known as multiple personality disorder). Doctors and psychotherapists have wrestled with how to help patients dealing with this diagnosis, but in reality, there is often doubt cast upon the validity of the symptoms.
Studies such as Boysen (2011) offer a retrospective analysis of the origins of symptoms and treatments presented in the literature in the 80s and 90s in an attempt to categorize the outcomes. However, there's no comparison with control cases or those who may have faced persistent, horrible abuse or other similar situations and not developed symptoms of the disorder.
Are there recent case control studies that have been done in this area of research? Is this careful retrospective analyis as far as we have progressed in determining whether these dissociative identities are a medical condition or artifacts of psychotherapy and popular press exposure?
Boysen, G.A. (2011) The scientific status of childhood dissociative identity disorder: A review of published research. Psychother Psychosom 2011;80:329-334. (DOI: 10.1159/000323403)