A very interesting article about the ever changing criteria for diagnosis of Borderline Personality disorder. To my mind there is no doubt that a mental disorder exists in those who display the symptoms, but in my experience it has been very difficult to identify BPD as a single identifiable disorder. One persona with whom I have had a lot of interaction displayed clear co-morbidity (Bulimia) and I found myself trying to work out whether one was the cause for the other. At other times she would display the characteristics of other disorders. To me the question isn’t does a disorder exist, it is clear to me that it does, but trying to define and identify the exact disorder is very difficult.

Source: Borderline personality disorder: The lability of psychiatric diagnosis : Current Psychiatry