“As an undergraduate student in psychology, I was taught that multiple personalities were a very rare and bizarre disorder. That is all that I was taught on ... It soon became apparent that what I had been taught was simply not true. Not only was I meeting people with multiplicity; these individuals entering my life were normal human beings with much to offer. They were simply people who had endured more than their share of pain in this life and were struggling to make sense of it.”
― Deborah Bray Haddock, The Dissociative Identity Disorder Sourcebook
Most current studies place the prevalence of dissociative identity disorder (DID) between 0.1% to 2%, though a few give estimations as high as 3-5%. The DSM-5 estimates the 12-month prevalence of DID as 1.5% of the population of American adults (American Psychiatric Association, 2013)1. While some studies find that DID is up to 9 times more common in females than males, other studies place the rates of prevalence equal for both groups or claim that males are slightly (approximately 0.2%)(American Psychiatric Association, 2013)1 more likely to have DID. It is thought that the discrepancy in diagnosis between males and females might be due to many males with DID not entering therapy or being incarcerated (a common explanation for diagnoses more commonly attributed to females). It's also thought that males may be more likely to deny their symptoms and trauma history. A discrepancy in diagnoses between genders is not visible in child or adolescent settings (American Psychiatric Association, 2013)1.
DID has been determined to affect between 7.5% to 10% of those in an inpatient setting (Ross, Duffy, & Ellason, 2002)2. DID was found to affect 6% of psychiatric inpatients in a Canadian hospital (Horen, Leichner, Lawson, 1995)3. In an American outpatient setting, it was found to affect 6% of the population (Foote et al., 2006)4.
It is frequently claimed that DID is a uniquely rare disorder. However, when comparing DSM-5 prevalence rates, this is simply not true. If a prevalence rate of 1.5% is accepted for DID, it is comparable in this way to chronic major depressive disorder (1.5%), bulimia nervosa among young females (1-1.5%), and obsessive compulsive disorder (1.1%-1.8%); it is more common than intellectual disability (1%), autism spectrum disorder (approaching 1%), schizophrenia (0.3%-0.7%), and persistent depressive disorder (dysthymia)(0.5%); and it is only slightly less common than panic disorder (2%-3%), adult ADHD (2.5%), and DSM-IV bipolar I, bipolar II, and bipolar disorder not otherwise specified combined (1.8%-2.7%) (American Psychiatric Association, 2013)1. That DID is more prevalent than autism spectrum disorder is perhaps most striking as it's often said that there's an autism "epidemic."
The prevalence rate of DID does vary between countries, but epidemiological general population studies still place the prevalence of DID at 1.1-1.5% and the prevalence of any DSM-IV dissociative disorder at 8.6-18.3% (Martinez-Taboas, Dorahy, Sar, Middleton, & Krügar, 2013)5.
1 American Psychiatric Association. (2013). Dissociative Disorders. In Diagnostic and statistical manual of mental disorders (5th ed.). http://dx.doi.org/10.1176/appi.books.9780890425596.dsm08
2 Ross, C., Duffy, C., & Ellason, J. (2002). Prevalence, reliability and validity of dissociative disorders in an inpatient setting [Abstract]. Journal of Trauma & Dissociation, 3(1). doi: 10.1300/J229v03n01_02
3 Horen, S., Leichner, P., & Lawson, J. (1995). Prevalence of dissociative symptoms and disorders in an adult psychiatric inpatient population in Canada [Abstract].The Canadian Journal of Psychiatry / La Revue Canadienne De Psychiatrie, 40(4), 185-191.
4 Foote, B., Smolin, Y., Kaplan, M., Legatt, M., & Lipschitz, D. (2006). Prevalence of dissociative disorders in psychiatric outpatients. American Journal of Psychiatry,163(4), 623-629. doi: 10.1176/appi.ajp.163.4.623
5 Martinez-Taboas, A., Dorahy, M., Sar, V., Middleton, W., & Krügar, C. (2013). Growing not dwindling: International research on the worldwide phenomena of dissociative disorders [Letter to the editor]. Journal of Nervous & Mental Disease, 201(4), 353.