Has multiple personality disorder remained consistent over time? A comparison of past and recent cases

The purpose of this study was to determine whether recent descriptions of multiple personality disorder are consistent with descriptions from the past. Clinical presentations and childhood histories obtained from early case reports of multiple personality disorder published between 1800 and 1965 (N = 52) were compared with recent case reports published in the 1980s (N = 54). Recent and past cases did not differ in age at diagnosis, length of treatment, duration of follow-up, presence of child and opposite gender personalities, and exposure to hypnosis. Recent cases differed significantly from past cases in mean number of personalities (12 vs. 3), age of onset (11 vs. 20 years), proportion of males (24% vs. 44%), and in prevalence of childhood abuse histories (81% vs. 29%). The authors discuss clinical and cultural factors that may have contributed to the change over time in the number of reported cases, complexity of personality structure, and description of etiological childhood trauma. Although a core set of symptoms has consistently been associated with this disorder over time, other important aspects have not been stable.