the middle stage, they recommended graded exposure techniques, along with appropriate interventions as needed. the treatment in the last stage was more individualized; few with dd became integrated into one identity. the first phase of therapy focuses on symptoms and relieving the distressing aspects of the condition, ensuring the safety of the individual, improving the patient's capacity to form and maintain healthy relationships, and improving general daily life functioning. comorbid disorders such as substance use disorder and eating disorders are addressed in this phase of treatment. the second phase focuses on stepwise exposure to traumatic memories and prevention of re-dissociation. the final phase focuses on reconnecting the identities of disparate alters into a single functioning identity with all its memories and experiences intact. a study was conducted to develop an "expertise-based prognostic model for the treatment of complex post-traumatic stress disorder (ptsd) and dissociative identity disorder (did)". researchers constructed a two-stage survey and factor analyses performed on the survey elements found 51 factors common to complex ptsd and did. the authors concluded from their findings: "the model is supportive of the current phase-oriented treatment model, emphasizing the strengthening of the therapeutic relationship and the patient's resources in the initial stabilization phase. further research is needed to test the model's statistical and clinical validity." prognosis little is known about prognosis of untreated did. it rarely, if ever, goes away without treatment, but symptoms may resolve from time to time or wax and wane spontaneously. patients with mainly dissociative and post-traumatic symptoms face a better prognosis than those with comorbid disorders or those still in contact with abusers, and the latter groups often face lengthier and more difficult treatment. suicidal ideation, suicide attempts, and self-harm also may occur. duration of treatment can vary depending on patient goals, which can range from merely improving inter-alter communication and cooperation, to reducing inter-alter amnesia, to integration of all alters, but generally takes years. epidemiology general according to the american psychiatric association, the 12-month prevalence of did among adults in the us is 1.5%, with similar prevalence between women and men. population prevalence estimates have been described to widely vary, with some estimates of did in inpatient settings suggesting 1-9.6%." reported rates in the community vary from 1% to 3% with higher rates among psychiatric patients. as of 2017, evidence suggested a prevalence of did of 2–5% among psychiatric inpatients, 2–3% among outpatients, and 1% in the general population, with rates reported as high as 16.4% for teenagers in psychiatric outpatient services. dissociative disorders in general have a prevalence of 12.0%–13.8% for psychiatric outpatients. as of 2012, did was diagnosed 5 to 9 times more common in women than men during young adulthood, although this may have been due to selection bias as men meeting did diagnostic criteria were suspected to end up in the criminal justice system rather than hospitals. in children, rates among men and women are approximately the same (5:4). did diagnoses are extremely rare in children; much of the research on childhood did occurred in the 1980s and 1990s and does not address ongoing controversies surrounding the diagnosis. did occurs more commonly in young adults and declines in prevalence with age. there is a poor awareness of did in the clinical settings and the general public. poor clinical education (or lack thereof) for did and other dissociative disorders has been described in literature: "most clinicians have been taught (or assume) that did is a rare disorder with a florid, dramatic presentation." symptoms in patients are often not easily visible, which complicates diagnosis. did has a high correlation with, and has been described as a form of, complex post-traumatic stress disorder. there is a significant overlap of symptoms between borderline personality disorder and did, although symptoms are understood to originate from different underlying causes. historical prevalence rates of diagnosed did were increasing in the late 20th century, reaching a peak of diagnoses at approximately 40,000 cases by the end of the 20th century, up from less than 200 diagnoses before 1970. initially did along with the rest of the dissociative disorders were considered the rarest of psychological conditions, diagnosed in less than 100 by 1944, with only one further case reported in the next two decades. in the late 1970s and '80s, the number of diagnoses rose sharply. an estimate from the 1980s placed the incidence at 0.01%. accompanying this rise was an increase in the number of alters, rising from only the primary and one alter personality in most cases, to an average of 13 in the mid-1980s (the increase in both number of cases and number of alters within each case are both factors in professional skepticism regarding the diagnosis). 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 charcot's 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. although research has appeared discussing the appearance of did in other countries and cultures and 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. etzel cardeña and david gleaves believed the overrepresentation of did in north america was the result of increased awareness and training about the condition. history one of ten photogravure portraits of louis vivet published in variations de la personnalité by henri bourru and prosper ferdinand burot early references in the 19th century, "dédoublement", or "double consciousness", the historical precursor to did, was frequently described as a state of sleepwalking, with scholars hypothesizing that the patients were switching between a normal consciousness and a "somnambulistic state". an intense interest in spiritualism, parapsychology and hypnosis continued throughout the 19th and early 20th centuries, running in parallel with john locke's views that there was an association of ideas requiring the coexistence of feelings with awareness of the feelings. hypnosis, which was pioneered in the late 18th century by franz mesmer and armand-marie jacques de chastenet, marques de puységur, challenged locke's association of ideas. hypnotists reported what they thought were second personalities emerging during hypnosis and wondered how two minds could coexist. the plaque on the former house of pierre marie félix janet (1859–1947), the philosopher and psychologist who first alleged a connection between events in the subject's past and present mental health, also coining the words "dissociation" and "subconscious" in the 19th century, there were a number of reported cases of multiple personalities which rieber estimated would be close to 100. epilepsy was seen as a factor in some cases, and discussion of this connection continues into the present era. by the late 19th century, there was a general acceptance that emotionally traumatic experiences could cause long-term disorders which might display a variety of symptoms. these conversion disorders were found to occur in even the most resilient individuals, but with profound effect in someone with emotional instability like louis vivet (1863–?), who had a traumatic experience as a 17-year-old when he encountered a viper. vivet was the subject of countless medical papers and became the most studied case of dissociation in the 19th century. between 1880 and 1920, various international medical conferences devoted time to sessions on dissociation. it was in this climate that jean-martin charcot introduced his ideas of the impact of nervous shocks as a cause for a variety of neurological conditions. one of charcot's students, pierre janet, took these ideas and went on to develop his own theories of dissociation. one of the first individuals diagnosed with multiple personalities to be scientifically studied was clara norton fowler, under the pseudonym christine beauchamp; american neurologist morton prince studied fowler between 1898 and 1904, describing her case study in his 1906 monograph, dissociation of a personality. 20th century in the early 20th century, interest in dissociation and multiple personalities waned for several reasons. after charcot's death in 1893, many of his so-called hysterical patients were exposed as frauds, and janet's association with charcot tarnished his theories of dissociation. sigmund freud recanted his earlier emphasis on dissociation and childhood trauma. in 1908, eugen bleuler introduced the term "schizophrenia" to represent a revised disease concept for emil kraepelin's dementia praecox. whereas kraepelin's natural disease entity was anchored in the metaphor of progressive deterioration and mental weakness and defect, bleuler offered a reinterpretation based on dissociation or "splitting" (spaltung) and widely broadened the inclusion criteria for the diagnosis. a review of the index medicus from 1903 through 1978 showed a dramatic decline in the number of reports of multiple personality after the diagnosis of schizophrenia became popular, especially in the united states. the rise of the broad diagnostic category of dementia praecox has also been posited in the disappearance of "hysteria" (the usual diagnostic designation for cases of multiple personalities) by 1910. a number of factors helped create a large climate of skepticism and disbelief; paralleling the increased suspicion of did was the decline of interest in dissociation as a laboratory and clinical phenomenon. starting in about 1927, there was a large increase in the number of reported cases of schizophrenia, which was matched by an equally large decrease in the number of multiple personality reports. with the rise of a uniquely american reframing of dementia praecox/schizophrenia as a functional disorder or "reaction" to psychobiological stressors – a theory first put forth by adolf meyer in 1906—many trauma-induced conditions associated with dissociation, including "shell shock" or "war neuroses" during world war i, were subsumed under these diagnoses. it was argued in the 1980s that did patients were often misdiagnosed with schizophrenia. the public, however, was exposed to psychological ideas which took their interest. mary shelley's frankenstein, robert louis stevenson's strange case of dr jekyll and mr hyde, and many short stories by edgar allan poe had a formidable impact. the three faces of eve in 1957, with the publication of the bestselling book the three faces of eve by psychiatrists corbett h. thigpen and hervey m. cleckley, based on a case study of their patient chris costner sizemore, and the subsequent popular movie of the same name, the american public's interest in multiple personality was revived. more cases of dissociative identity disorder were diagnosed in the following years. the cause of the sudden increase of cases is indefinite, but it may be attributed to the increased awareness, which revealed previously undiagnosed cases or new cases may have been induced by the influence of the media on the behavior of individuals and the judgement of therapists. during the 1970s an initially small number of clinicians campaigned to have it considered a legitimate diagnosis. history in the dsm the dsm-ii used the term hysterical neurosis, dissociative type. it described the possible occurrence of alterations in the patient's state of consciousness or identity, and included the symptoms of "amnesia, somnambulism, fugue, and multiple personality". the dsm-iii grouped the diagnosis with the other four major dissociative disorders using the term "multiple personality disorder". the dsm-iv made more changes to did than any other dissociative disorder, and renamed it did. the name was changed for two reasons: first, the change emphasizes the main problem is not a multitude of personalities, but rather a lack of a single, unified identity and an emphasis on "the identities as centers of information processing". second, the term "personality" is used to refer to "characteristic patterns of thoughts, feelings, moods,