Day # 112: Dissociative Disorders - The "who" and the "why"

Welcome back to our current topic of dissociative disorders. Today we are going to go one level deeper and overview some epidemiology, risk factors, and the typical course and prognosis of dissociative disorders.


Today’s Content Level: Intermediate



DISSOCIATIVE IDENTITY DISORDER (DID)


Epidemiology 1, 2

  • Prevalence: 12-month prevalence ~1-1.5% in non-clinical populations. Estimates of 2.5% (outpatient psychiatry) and 3.5% (inpatient psychiatry).

  • Gender: ~1:1 female to male ratio.

  • Suicide risk: >70% of patients attempt suicide, often with frequent attempts and self-injurious behaviors.


Pathogenesis 3, 4

  • Genetic risk: At this point, no direct examination of genetics has occurred in DID. However, it is likely to exist, given the genetic link to dissociation in general and in relation to childhood adversity.

  • Trauma: DID predominantly develops in victims of significant chronic or childhood trauma. Childhood physical or sexual abuse or neglect is present in >90% of patients. Other reported forms of trauma include childhood medical procedures, prostitution, or terrorism. More severe and earlier-onset of child abuse appears to differentiate DID from other disorders.

  • Temperment/Personality: Some data suggests that disorganized attachment style may increase the risk of DID.

  • Pathophysiology: After traumatic events, memory and the construction of self-identity are cognitive processes that appear markedly disrupted in DID. Some evidence implicates the presence of smaller hippocampal and amygdala volumes in patients with DID and the severity of dissociation is negatively correlated with hippocampal volume.


Course and Prognosis 5

  • Course: May manifest at any age, but some symptoms are usually present in childhood. Course is typically fluctuating but chronic.

  • Prognosis: Worst prognosis of all dissociative disorders. Symptoms may become triggered by a number of life events including later traumatic experiences, removal from the traumatizing situation, illness/death of their abuser(s), or their children reaching the same age at which they were abused.

  • Comorbidities: High incidence of comorbid PTSD, major depression, eating disorders, personality disorders (borderline and avoidant), substance use disorders, sleep disorders, and functional neurologic disorders.



DISSOCIATIVE AMNESIA


Epidemiology 6, 7, 8

  • Prevalence: Prevalence is not well-established and differs substantially across countries and populations. 12-month prevalence reported anywhere from 1-7.8% (the study cited in the DSM-5 says 1.8%).

  • Gender: More common in women than men, however likely under diagnosed in males.

  • Suicide risk: Increased risk but unclear statistics. Suicidal behavior may be a particular risk when the amnesia remits suddenly and overwhelms the individual with intolerable memories.


Pathogenesis 9

  • Genetic risk: At this point, no direct examination of genetics has occurred in dissociative amnesia. However, it is likely to exist, given the genetic link to dissociation in general and in relation to childhood adversity.

  • Trauma: Single or repeated traumas often occur prior to amnesia. Reported cases include repeated childhood physical or sexual abuse, interpersonal violence, war, terrorism, and genocide.


Course and Prognosis 10

  • Course: The onset of generalized amnesia is usually abrupt. The course of symptoms varies. Some episodes of amnesia may resolve rapidly whereas other episodes persist for long periods of time. In between episodes of amnesia, the individual may or may not appear to be symptomatic.

  • Prognosis: Increased severity, frequency, and violence of the trauma are predictors of a less favorable prognosis.

  • Comorbidities: Higher incidence of depressive disorders, PTSD, somatic symptom disorder, functional neurologic disorder, and personality disorders (especially borderline, avoidant, and dependent).



DEPERSONALIZATION / DEREALIZATION DISORDER


Epidemiology 11, 12, 13

  • Prevalence: Lifetime prevalence the disorder is ~1-2%. Brief experiences of depersonalization/derealization are common with approximately ~50% of the general population experiencing at least one lifetime episode, and an estimated 23% annual prevalence. Common with recreational drug use.

  • Gender: ~1:1 female to male ratio.

  • Suicide risk: Dissociative disorders are commonly overlooked in studies of suicidality, but some studies show they can be the strongest predictor of multiple suicide attempter status.


Pathogenesis 15

  • Genetic risk: At this point, no direct examination of genetics has occurred in depersonalization/derealization disorder. However, it is likely to exist, given the genetic link to dissociation in general and in relation to childhood adversity.

  • Trauma: Severe stress or traumas are predisposing factors, although this is not as strongly associated or as extreme as seen in the other dissociative disorders. The strongest and most consistent association is with emotional abuse or neglect, but also includes physical or sexual abuse, witnessing domestic violence, or unexpected death of a family member.

  • Temperment/Personality: Increased risk in individuals with immature defenses (projection, acting out, idealization/devaluation), harm-avoidant temperament, and both disconnection and overcorrection schemata (dependency, vulnerability, and incompetence).

  • Pathophysiology: These symptoms may specifically induced by a number of substances (example: ketamine, THC, MDMA). Ongoing research on the pathophysiology of these experiences focuses on fMRI/MRI imaging, genotype/phenotype variation, and neurophysiology.


Course and Prognosis 16

  • Course: Average age of onset is 16 years old, but typically starts in adolescence to late 20's. Often persistent but may wax and wane. Duration and frequency of episodes vary. According to DSM-5, there are roughly 1/3 of cases that involve discrete episodes, 1/3 have continuous symptoms from the start, and another 1/3 start with an episodic course that eventually becomes continuous.

  • Comorbidities: Increased incidence of depressive and anxiety disorders.



CONCLUSION


I hope today's lesson provided a nice overview about the "who" and the "why" of dissociative disorders. In our next post we will discuss clinical pearls for dissociative disorders.


Resources for this post include Pocket Psychiatry, Kaplan and Sadock comprehensive psychiatry, DSM-5, and First Aid For the Psychiatry Clerkship as well as the articles referenced in the post.
























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