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.
What may be expressed as post-traumatic stress disorder (PTSD) in adults may become DID when occurring in children, possibly due to their greater use of imagination as a form of coping.Possibly due to developmental changes and a more coherent sense of self past the age of six, the experience of extreme trauma may result in different, though also complex, dissociative symptoms and identity disturbances. A specific relationship between childhood abuse, disorganized attachment, and lack of social support are thought to be a necessary component of DID. Although what role a childs biological capacity to dissociate to an extreme level remains unclear, some evidence indicates a neurobiological impact of developmental stress.Delinking early trauma from the etiology of dissociation has been explicitly rejected by those supporting the early trauma model. However, a 2012 review article supports the hypothesis that current or recent trauma may affect an individuals assessment of the more distant past, changing the experience of the past and resulting in dissociative states. Giesbrecht et al. have suggested there is no actual empirical evidence linking early trauma to dissociation, and instead suggest that problems with neuropsychological functioning, such as increased distractibility in response to certain emotions and contexts, account for dissociative features. A middle position hypothesizes that trauma, in some situations, alters neuronal mechanisms related to memory. Evidence is increasing that dissociative disorders are related both to a trauma history and to "specific neural mechanisms".