it is an undeniable fact that there are many individuals who meet DSM criteria for dissociative identity disorder. nobody denies that. it is an undeniable fact that the individuals who meet DSM criteria for dissociative identity disorder are in a lot of pain. nobody denies that.

one issue of debate is over whether DID is a culture bound syndrome (like hysterical paralysis and demonic possession and dissociative fugue was in France) or whether it is universal like depression. Harrison Pope (biological psychiatry, Harvard) has offered USD$1,000 to the first person to come up with an uncontroversial case of recovered memory prior to 1800, for example. There is also a great deal of controversy over whether there is an uncontroversial case of schizophrenia prior to the industrial revolution, however (which is to say that it is also debated whether schizophrenia is culture bound or universal). Interestingly people have posited a pathogen that was prevalent during the industrial revolution for schizophrenia whereas the development of technologies to recover memories (psychoanalysis) doesn't seem to have been considered on a par...

this issue seems to come down to how much the symptoms of dissociative identity disorder are a fairly invarient expressions of the underlying pathology and how much the symptoms of dissociative identity disorder are shaped by social causal mechanisms (such as interested therapists and the like). one notion is that there was demonic possession when that was considered a legitimate way of expressing distress and then there was hysterical paralysis when that was considered a legitimate way of expressing distress and now there is dissociative identity disorder...

it is a shame that many people have embraced polarities and talk about whether the disorder 'exists' or not. as i said, nobody denies that individuals meet criteria. what is debated is how the individuals got to be that way (e.g., is trauma a cause or merely a contributing factor, is the media and clinicians introducing the phenomena into popular culture a cause or merely a contributing factor etc). as always 'a bit of both and a whole lot more besides' is probably a fairer (and truer) picture.