• Clinical science

Dissociative disorders


Dissociative disorders are psychiatric conditions characterized by disruption and/or discontinuity of normal consciousness, memory, identity, and perception. Abnormalities may also be seen in behavior, control of motor functions, and body representation. The disorders are typically seen in individuals with a history of very stressful or traumatic events and often manifest already in childhood. DSM-5 recognizes the following types: dissociative identity disorder, dissociative amnesia (with or without dissociative fugue), depersonalization disorder, as well as other specified dissociative disorder and unspecified dissociative disorder. Patients usually experience positive dissociative symptoms such as derealization, fragmentation of identity, and depersonalization (i.e., intrusive and involuntary changes in awareness and behavior) and/or negative dissociative symptoms, such as amnesia or difficulties controlling mental functions. Dissociative disorders are often associated with other psychiatric symptoms and conditions, including anxiety, depression, somatic symptom disorders, and eating disorders.


  • Dissociation (nonpathological form): a psychological defense mechanism (natural protective response) to a traumatic or very stressful experience.
    • Disruption of normal integration of memories, identity, perception, experiences, and emotions to cope with stress or stimulation overload
    • Detachment from self (physical and emotional experiences) and/or surroundings
    • Can be a fleeting phenomenon (e.g. daydreaming) or more severe with impaired consciousness
  • Pathological dissociation: an excessive reaction to a traumatic or very stressful experience that is characterized by:
    • Positive symptoms: derealization; (the mind detaches from one's environment), fragmentation of identity; , and depersonalization (the mind detaches from one's self)
    • Negative symptoms: amnesia; , altered consciousness (e.g., narrowed awareness, trance), altered behavior


Dissociative amnesia

  • Epidemiology: most common dissociative disorder; (lifetime prevalence ∼ 7%); more common in women than in men
  • Diagnostic criteria
    1. Inability to recall autobiographical information, typically of a traumatic or stressful event , that is distinct from ordinary forgetting
      • Can be described as localized (i.e. amnesia of a single event or time period), selective (i.e. amnesia of a specific aspect of an occurrence), or generalized (i.e. amnesia of personal history and identity)
    2. Symptoms cause significant social or occupational impairment.
    3. Symptoms are not due to substance use or another medical condition.
    4. Symptoms cannot be explained better by another psychiatric disorder (e.g., dissociative identity disorder, acute stress disorder, or posttraumatic stress disorder).
    5. May present with dissociative fugue: wandering or purposeful travel; associated with amnesia of identity or autobiographical information
  • Treatment: psychotherapy; no effective pharmacotherapy available
  • Prognosis
    • Temporarily inaccessible memories are often retrievable or return naturally
    • Rarely generalizes, but can cause complete memory loss
    • Associated with concurrent major depressive disorder and increased risk for suicide

Patients may experience the return of memories as nightmares or flashbacks. The complete resolution of amnesia and full return of memory may be overwhelming and coincide with an increased risk for suicide!


Depersonalization/derealization disorder

  • Epidemiology: lifetime prevalence ∼ 2%; average age at onset 16 years
  • Diagnostic criteria
    1. Recurrent or persistent episodes of depersonalization and/or derealization
      • Depersonalization: sense of unreality with detachment from oneself (e.g., body perception, feelings, thoughts, actions)
      • Derealization: sense of unreality with detachment from one's environment
    2. Reality testing is intact during these episodes.
    3. Symptoms cause significant social or occupational impairment.
    4. Symptoms are not due to substance use or another medical condition.
    5. Symptoms cannot be better explained by another psychiatric disorder (e.g., schizophrenia, major depressive disorder, panic disorder, acute stress disorder, PTSD, other dissociative disorders)
  • Treatment: cognitive behavioral therapy, hypnotherapy, psychodynamic therapy
  • Prognosis
    • Often persistent, with fluctuations in severity
    • Increased risk for concurrent major depression and anxiety disorders

Patients with a depersonalization/derealization disorder may report out-of-body experiences or a feeling of being in a dream.


Dissociative identity disorder

  • Epidemiology
    • Rare (prevalence < 1%)
    • More prevalent in women
    • May manifest at any age
    • Very common in patients with a history of physical/sexual abuse and/or neglect during childhood (90% of patients)
  • Diagnostic criteria
    1. Alternation of at least two separate personality states that cause identity disruption and dominate at different times
      • Involves discontinuity in sense of self (depersonalization) and agency; altered affect, memory, behavior, perception, consciousness, cognition and/or sensory-motor functioning (derealization)
    2. Frequent gaps in recall of normal daily events or personal information that are significantly different from ordinary forgetfulness
    3. Symptoms cause the patient significant social or occupational impairment.
    4. Symptoms are not related to substance use, another medical condition, or a broadly accepted religious or cultural practice.
  • Treatment: psychotherapy; SSRIs for comorbid conditions (depression, PTSD)
  • Prognosis
    • Chronic disease course with fluctuations in severity
    • Increased risk of other psychiatric conditions (major depression, borderline personality disorder, PTSD, eating disorders, substance use disorders)
    • High rates of self-harm and suicide

Patients are often unaware of the other personalities and describe a feeling of being possessed or experiencing frequent gaps in recall.



Other specified dissociative disorder

  • Definition: classification for symptom constellations that are typical for dissociative disorders and cause significant social or occupational impairment, but do not fully match the definitions of the disorders listed above; diagnosis based on the leading feature of the patient's disorder (e.g., dissociative trance)
  • Examples
    • Chronic and recurrent syndromes of mixed dissociative symptoms: slight disturbance in identity and sense of agency or identity alterations or episodes of possession in patients without dissociative amnesia
    • Identity disturbance due to prolonged and intense coercive persuasion: prolonged alterations or conscious questioning of identity after being subjected to intense coercive persuasion (e.g., torture, brain washing, thought reform, recruitment by cults or terror organizations, political imprisonment)
    • Acute dissociative reactions to stressful events: transient conditions that generally last less than 1 month, but can be as short as a few hours or days; characterized by depersonalization, derealization, perceptual disturbances, micro-amnesia, constriction of consciousness and/or changes in sensory-motor functioning (e.g., analgesia, paralysis)
    • Dissociative trance: decreased or complete loss of awareness of immediate surroundings that presents as profound unresponsiveness or insensitivity to external stimuli; further symptoms include transient paralysis, loss of consciousness, or uncontrollable, stereotypical behaviors (e.g., rocking, repetitive finger movements) of which patients are unaware