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Module 6: Dissociative Disorders

3rd edition as of July 2023


Module Overview

In Module 6, we will discuss matters related to dissociative disorders to include their clinical presentation, epidemiology, comorbidity, etiology, and treatment options. Our discussion will consist of dissociative identity disorder, dissociative amnesia, and depersonalization/ derealization.  Be sure you refer Modules 1-3 for explanations of key terms (Module 1), an overview of models to explain psychopathology (Module 2), and descriptions of the various therapies (Module 3).


Module Outline


Module Learning Outcomes

  • Describe how dissociative disorders present.
  • Describe the epidemiology of dissociative disorders.
  • Describe comorbidity in relation to dissociative disorders.
  • Describe the etiology of dissociative disorders.
  • Describe treatment options for dissociative disorders.


6.1. Clinical Presentation


Section Learning Objectives

  • Describe dissociative disorders.
  • Describe how dissociative identity disorder presents.
  • Describe how dissociative amnesia presents.
  • Describe how depersonalization/derealization presents.


Dissociative disorders are a group of disorders characterized by symptoms of disruption and/or discontinuity in consciousness, memory, identity, emotion, body representation, perception, motor control, and behavior (APA, 2022). These symptoms are likely to appear following a significant stressor or years of ongoing stress (i.e., abuse; Maldonadao & Spiegel, 2014).  Occasionally, one may experience temporary dissociative symptoms due to lack of sleep or ingestion of a substance; however, these would not qualify as a dissociative disorder due to the lack of impairment in functioning. Furthermore, individuals who suffer from acute stress disorder and PTSD often experience dissociative symptoms, such as amnesia, numbing, flashbacks, and depersonalization/derealization. However, because of the identifiable stressor (and lack of additional symptoms listed below), they meet diagnostic criteria for a stress disorder as opposed to a dissociative disorder.

There are three main types of dissociative disorders: dissociative identity disorder, dissociative amnesia, and depersonalization/derealization disorder.


6.1.1. Dissociative Identity Disorder (DID)

The key diagnostic criteria for dissociative identity disorder is the presence of two or more distinct personality states or an experience of possession (Criteria A). How overt or covert the personality states are depends on psychological motivation, stress level, cultural context, emotional resilience, and internal conflicts and dynamics (APA, 2022), and severe or prolonged stress may result in sustained periods of identify confusion/alteration. Those presenting as being possessed by spirits or demons and for a small proportion of non-possession-form cases, the alternate identifies are readily observable. Generally, though, the identities in non-possession-form dissociative identity disorder are not overtly displayed or only subtly displayed and when they are, it is just in a minority of individuals and manifests as different names, hairstyles, handwritings, wardrobes, accents, etc. If the alternate identities are not observable, their presence is identified through sudden alterations or discontinuities in the individual’s sense of self and sense of agency, as well as recurrent dissociative amnesias (see the second criteria below; APA, 2022).

The second main diagnostic criteria (Criteria B) for dissociative identity disorder is that there must be a gap in the recall of events, information, or trauma due to the switching of personalities. These gaps are more excessive than typical forgetting one may experience due to a lack of attention. The dissociative amnesia presents as gaps in autobiographical memory, lapses in memory of well-learned skills or recent events, and discovering possessions for which there is no recollection of ever owning, and can involve everyday events and not just events that are stressful or traumatic.

It should be noted that most possession states occurring around the world are part of broadly accepted cultural or religious practice and should not be diagnosed as dissociative identity disorder (Criteria D). The possession-form identities in dissociative identity disorder manifest most often as a spirit or supernatural being taking control and the individual speaking or acting in a distinctly different way. These identities present recurrently, are involuntary and unwanted, and cause significant distress or impairment (Criteria C). Impairment varies in adults from minimal (i.e., high functioning professionals) to profound. For those minimally affected, marital, family, relational, and parenting functions are more likely to be impaired by symptoms of dissociative identity disorder rather than their occupational and professional life.

While personalities can present at any time, there is generally a dominant or primary personality that is present most of the time. From there, an individual may have several subpersonalities. Although it is hard to identify how many subpersonalities an individual may have at one time, it is believed that there are on average 15 subpersonalities for women and 8 for men (APA, 2000).

The switching or shifting between personalities varies among individuals and can range from merely appearing to fall asleep, to very dramatic, involving excessive bodily movements, though for most, the change is subtle and may occur with only subtle changes in overt presentation. When sudden and unexpected, switching is generally precipitated by a significant stressor, as the subpersonality best equipped to handle the current stressor will present. The relationship between subpersonalities varies between individuals, with some individuals reporting knowledge of other subpersonalities while others have a one-way amnesic relationship with subpersonalities, meaning they are not aware of other personalities (Barlow & Chu, 2014). These individuals will experience episodes of “amnesia” when the primary personality is not present.


6.1.2. Dissociative Amnesia

Dissociative amnesia is identified by the inability to recall important autobiographical information, usually of a traumatic or stressful nature. It often consists of selective amnesia for a specific event or events or generalized amnesia for identity and life history. This type of amnesia is different from what one would consider permanent amnesia in that the information was successfully stored in memory but cannot be freely recollected. It is conceptualized as possibly being a reversible memory retrieval deficit. Additionally, individuals experiencing permanent amnesia often have a neurobiological cause, whereas dissociative amnesia does not (APA, 2022).

There are a few types of amnesia within dissociative amnesia. Localized amnesia, the most common type, is the inability to recall events during a specific period. The length of time within a localized amnesia episode can vary—it can be as short as the time immediately surrounding a traumatic event, to months or years, should the traumatic event occur that long (as commonly seen in abuse and combat situations). Selective amnesia is, in a sense, a component of localized amnesia in that the individual can recall some, but not all, of the details during a specific period. For example, a soldier may experience dissociative amnesia during the time they were deployed, yet still have some memories of positive experiences such as celebrating Thanksgiving or Christmas dinner with the members of their unit. Systematized amnesia occurs when an individual fails to recall a specific category of information such as not recalling a specific room in their childhood home.

Conversely, some individuals experience generalized dissociative amnesia in which they have a complete loss of memory for most or all of their life history, including their own identity, previous knowledge about the world, and/or well-learned skills. Individuals who experience this amnesia experience deficits in both semantic and procedural knowledge. This means that individuals have no common knowledge of (i.e., cannot identify letters, colors, numbers) nor can they engage in learned skills (i.e., typing shoes, driving car). While generalized dissociative amnesia is extremely rare, it is also extremely frightening. The onset is acute, and the individual is often found wandering in a state of disorientation. Many times, these individuals are brought into emergency rooms by law enforcement following a dangerous situation such as an individual wandering on a busy road.

The distress and impairment suffered by those with dissociative amnesia resulting from childhood/adolescent traumatization varies. Some are chronically impaired in their ability to form and sustain satisfactory attachments while others are highly successful in their occupation due to compulsive overwork. And finally, a substantial subgroup of those afflicted by generalized dissociative amnesia develop a highly impairing, chronic autobiographical memory deficit that is not ameliorated by relearning their life history, resulting in poor overall functioning in most life domains (APA, 2022).


6.1.3. Depersonalization/Derealization Disorder

Depersonalization/derealization disorder is categorized by recurrent episodes of depersonalization and/or derealization. Depersonalization can be defined as a feeling of unreality or detachment from oneself. Individuals describe this feeling as an out-of-body experience where you are an observer of your thoughts, feelings, and physical being. Furthermore, some patients report feeling as though they lack speech or motor control, thus feeling at times like a robot. Distortions of one’s physical body have also been reported, with various body parts appearing enlarged or shrunken. Emotionally, one may feel detached from their feelings, lacking the ability to feel emotions despite knowing they have them.

Symptoms of derealization include feelings of unreality or detachment from the world—whether it be individuals, objects, or their surroundings. For example, an individual may feel as though they are unfamiliar with their surroundings, even though they are in a place they have been to many times before. Feeling emotionally disconnected from close friends or family members whom they have strong feelings for is another common symptom experienced during derealization episodes. Sensory changes have also been reported, such as feeling as though your environment is distorted, blurry, or even artificial. Distortions of time, distance, and size/shape of objects may also occur.

These episodes can last anywhere from a few hours to days, weeks, or even months. The onset is generally sudden, and like the other dissociative disorders, is often triggered by intense stress or trauma. Many individuals describe feeling like they are “crazy” or “going crazy” and fear they have irreversible brain damage. They experience an altered sense of time and may be obsessed about whether they really exist.

As one can imagine, depersonalization/derealization disorder can cause significant emotional distress, as well as impairment in one’s daily functioning. The disorder is associated with major morbidity and impairment occurs in both interpersonal and occupational spheres due to “…the hypoemotionality with others, subjective difficulty in focusing and retaining information, and a general sense of disconnectedness form life” (APA, 2022).


Key Takeaways

You should have learned the following in this section:

  • Dissociative disorders are characterized by disruption in consciousness, memory, identity, emotion, perception, motor control, or behavior. They include dissociative identity disorder, dissociative amnesia, and depersonalization/derealization disorder.
  • Dissociative identity disorder is the presence of two or more distinct personality states or an experience of possession.
  • Dissociative amnesia is characterized by the inability to recall important autobiographical information, whether during a specific period (localized) or one’s entire life (generalized).
  • Depersonalization/derealization disorder includes a feeling of unreality or detachment from oneself (depersonalization) and feelings of unreality or detachment from the world (derealization).


Section 6.1 Review Questions

  1. Identify the diagnostic criteria for each of the three dissociative disorders. How are they similar? How are they different?
  2. What are the types of amnesia within dissociative amnesia?
  3. What is the difference between depersonalization and derealization?



6.2. Epidemiology


Section Learning Objectives

  • Describe the epidemiology of dissociative disorders.


Dissociative disorders were once believed to be extremely rare; however, more recent research suggests that they may be more present in the general population than once thought. Estimates for the prevalence of dissociative identity disorder in U.S. adults is 1.5%, with women predominating in adult clinical settings. Symptom profiles, clinical history, and childhood trauma history show few gender differences though women have higher rates of somatization. Research shows that dissociative amnesia occurs in approximately 1.8% of the U.S. population. It is estimated that about one-half of all adults have experienced at least one episode of depersonalization/derealization during their life, however, symptomatology that meets full criteria for the disorder is markedly less common than these transient symptoms. A one-month prevalence of about 1-2% was reported in the United Kingodm (APA, 2022).

The onset of dissociative disorders is generally late adolescence to early adulthood, with the exception of dissociative identity disorder. Due to the high comorbidity between childhood abuse and dissociative identity disorder, it is believed that symptoms begin in early childhood following the repeated exposure to abuse; however, the full onset of the disorder is not observed (or noticed by others) until adolescence (Sar et al., 2014).


Key Takeaways

You should have learned the following in this section:

  • Dissociative identity disorder has a prevalence of 1.5% and dissociative amnesia occurs in approximately 1.8% of the U.S. population.
  • Estimates for depersonalization/derealization disorder are unknown, though it is believed that about half of all adults have experienced at least one episode during their life (i.e. transient symptoms and not full criteria).


Section 6.2 Review Questions

  1. What are the prevalence rates for dissociative disorders? What are some identified barriers in determining prevalence rates of these disorders?


6.3. Comorbidity


Section Learning Objectives

  • Describe the comorbidity of dissociative disorders.


Given that a traumatic experience often precipitates dissociative disorders, it should not be surprising that there is a high comorbidity between most dissociative disorders and PTSD (comorbidity of depersonalization/derealization disorder with PTSD is low). Similarly, depressive disorders are also commonly found in combination with dissociative disorders, likely due to the impact the disorders have on social and emotional functioning. In individuals with dissociative amnesia, a wide range of emotions related to their inability to recall memories during the episode often present once the amnesia episode is in remission (APA, 2022). These emotions frequently contribute to the development of a depressive episode.

There has been some evidence of comorbid somatic symptom disorder and conversion disorder, particularly for those who experience dissociative amnesia. Furthermore, dependent, obsessive-compulsive, avoidant, and borderline personality traits/disorders are comorbid and for dissociative identity disorder and dissociative amnesia there is evidence of comorbid substance-related and feeding and eating disorders. Anxiety disorders are common for depersonalization/derealization disorder, and often individuals concurrently have unipolar depressive disorder.


Key Takeaways

You should have learned the following in this section:

  • Many dissociative disorders have been found to have a high comorbidity with PTSD and depressive disorders.
  • Somatic symptom and conversion disorders, as well as some personality disorders, have also been found to be comorbid.


Section 6.3 Review Questions

  1. What are the common comorbid diagnoses for individuals with dissociative disorders?



6.4. Etiology


Section Learning Objectives

  • Describe the biological causes of dissociative disorders.
  • Describe the cognitive causes of dissociative disorders.
  • Describe the sociocultural causes of dissociative disorders.
  • Describe the psychodynamic causes of dissociative disorders.


6.4.1. Biological

While studies on the involvement of genetic underpinnings need additional research, there is some suggestion that heritability rates for dissociation rage from 50-60% (Pieper, Out, Bakermans-Kranenburg, Van Ijzendoorn, 2011). However, it is suggested that the combination of genetic and environmental factors may play a larger role in the development of dissociative disorders than genetics alone (Pieper, Out, Bakermans-Kranenburg, Van Ijzendoorn, 2011).


6.4.2. Cognitive

One proposed cognitive theory of dissociative disorders, particularly dissociative amnesia, is a memory retrieval deficit. More specifically, Kopelman (2000) theorizes that the combination of psychological stress and various other biopsychosocial predispositions affects the frontal lobes executive system’s ability to retrieve autobiographical memories (Picard et al., 2013). Neuroimaging studies have supported this theory by showing deficits to several prefrontal regions, which is one area responsible for memory retrieval (Picard et al., 2013).   Despite these findings, there is still some debate over which specific brain regions within the executive system are responsible for the retrieval difficulties, as research studies have reported mixed findings.

Specific to dissociative identity disorder, neuroimaging studies have shown differences in hippocampus activation between subpersonalities (Tsai, Condie, Wu & Chang, 1999). As you may recall, the hippocampus is responsible for storing information from short-term to long-term memory. It is hypothesized that this brain region is responsible for the generation of dissociative states and amnesia (Staniloiu & Markowitsch, 2010).


6.4.3. Sociocultural

The sociocultural model of dissociative disorders has been primarily influenced by Lilienfeld and colleagues (1999) who argue that the influence of mass media and its publications of dissociative disorders, provide a model for individuals to not only learn about dissociative disorders but also engage in similar dissociative behaviors. This theory has been supported by the significant increase in dissociative identity disorder cases after the publication of Sybil, a documentation of a woman’s 16 subpersonalities (Goff & Simms, 1993).

These mass media productions are not just suggestive to patients. It has been suggested that mass media also influences the way clinicians gather information regarding dissociative symptoms of patients. For example, therapists may unconsciously use questions or techniques in session that evoke dissociative types of problems in their patient following exposure to a media source discussing dissociative disorders.


6.4.4. Psychodynamic

The psychodynamic theory of dissociative disorders assumes that dissociative disorders are caused by an individual’s repressed thoughts and feelings related to an unpleasant or traumatic event (Richardson, 1998). In blocking these thoughts and feelings, the individual is subconsciously protecting himself from painful memories.

While a single incidence of repression may explain dissociative amnesia, psychodynamic theorists believe that dissociative identity disorder results from repeated exposure to traumatic experiences, such as childhood abuse, neglect, or abandonment (Dalenberg et al., 2012). According to the psychodynamic perspective, children who experience repeated traumatic events such as physical abuse or parental neglect lack the support and resources to cope with these experiences. To escape from their current situation, children develop different personalities to essentially flee the dangerous situation they are in. While there is limited scientific evidence to support this theory, the nature of severe childhood psychological trauma is consistent with this theory, as individuals with dissociative identity disorder have the highest rate of childhood psychological trauma compared to all other psychiatric disorders (Sar, 2011).


Key Takeaways

You should have learned the following in this section:

  • Though there is some evidence for a genetic component to dissociative disorders, a combination of genes and environment are thought to play a larger role.
  • A cognitive explanation assumes a memory retrieval deficit, particularly related to dissociative amnesia, and differential hippocampus activation between subpersonalities in dissociative identity disorder.
  • Mass media is also purported to have caused a rise in dissociative disorders due to the attention it gives these disorders in its publications and movies such as Sybil.
  • Finally, repressed thoughts and feelings are thought to be the cause of dissociative disorders in the psychodynamic theory.


Section 6.4 Review Questions

  1. How do the biological, cognitive, sociocultural, and psychodynamic perspectives differ in their explanation of the development of dissociative disorders?



6.5. Treatment


Section Learning Objectives

  • Clarify why treatment for dissociative disorders is limited.
  • Describe treatment options for dissociative identity disorder.
  • Describe treatment options for dissociative amnesia.
  • Describe treatment options for depersonalization/derealization disorder.


Treatment for dissociative disorders is limited for a few reasons. First, with respect to dissociative amnesia, many individuals recover on their own without any intervention. Occasionally treatment is sought out after recovery due to the traumatic nature of memory loss. Second, the rarity of these disorders has offered limited opportunities for research on both the development and effectiveness of treatment methods. Due to the differences between dissociative disorders, treatment options will be discussed specific to each disorder.


6.5.1. Dissociative Identity Disorder

The ultimate treatment goal for dissociative identity disorder is the integration of subpersonalities to the point of final fusion (Chu et al., 2011). Integration refers to the ongoing process of merging subpersonalities into one personality. Psychoeducation is paramount for integration, as the individual must understand their disorder, as well as acknowledge their subpersonalities. As mentioned above, many individuals have a one-way amnesic relationship with the subpersonalities, meaning they are not aware of one another. Therefore, the clinician must first make the individual aware of the various subpersonalities that present across different situations.

Achieving integration requires several steps. First, the clinician needs to build a relationship and strong rapport with the primary personality. From there, the clinician can begin to encourage communication and coordination between the subpersonalities gradually. Making the subpersonalities aware of one another, as well as addressing their conflicts, is an essential component of the integration of subpersonalities, and the core of dissociative identity disorder treatment (Chu et al., 2011).

Once the individual is aware of their personalities, treatment can continue with the goal of fusion. Fusion occurs when two or more alternate identities join (Chu et al., 2011). When this happens, there is a complete loss of separateness. Depending on the number of subpersonalities, this process can take quite a while. Once all subpersonalities are fused and the individual identifies themselves as one unified self, it is believed the patient has reached final fusion.

It should be noted that final fusion is difficult to obtain. As you can imagine, some patients do not find final fusion a desirable outcome, particularly those with harrowing histories; chronic, severe stressors; advanced age; and comorbid medical and psychiatric disorders, to name a few. For individuals where final fusion is not the treatment goal, the clinician may work toward resolution or sufficient integration and coordination of subpersonalities that allows the individual to function independently (Chu et al., 2011). Unfortunately, individuals that do not achieve final fusion are at greater risk for relapse of symptoms, particularly those with whose dissociative identity disorder appears to stem from traumatic experiences.

Once an individual reaches final fusion, ongoing treatment is essential to maintain this status. In general, treatment focuses on social and positive coping skills. These skills are particularly helpful for individuals with a history of traumatic events, as it can help them process these events, as well as help prevent future relapses.


6.5.2. Dissociative Amnesia

As previously mentioned, many individuals regain memory without the need for treatment; however, there is a small population that does require additional treatment. While there is no evidenced-based treatment for dissociative amnesia, both hypnosis and phasic therapy have been shown to produce some positive effects in patients with dissociative amnesia. Hypnosis. One theory of dissociative amnesia is that it is a form of self-hypnosis and that individuals hypnotize themselves to forget information or events that are unpleasant (Dell, 2010). Because of this theory, one type of treatment that has routinely been implemented for individuals with dissociative amnesia is hypnosis. Through hypnosis, the clinician can help the individual contain, modulate, and reduce the intensity of the amnesia symptoms, thus allowing them to process the traumatic or unpleasant events underlying the amnesia episode (Maldonadao & Spiegel, 2014). To do this, the clinician will encourage the patient to think of memories just before the amnesic episode as though it was the present time. The clinician will then slowly walk them through the events during the amnesic period to reorient the individual to experience these events. This technique is essentially a way to encourage a controlled recall of dissociated memories, something that is particularly helpful when the memories include traumatic experiences (Maldonadao & Spiegel, 2014).

Another form of “hypnosis” is the use of barbiturates, also known as “truth serums,” to help relax the individual and free their inhibitions. Although not always effective, the theory is that these drugs reduce the anxiety surrounding the unpleasant events enough to allow the individual to recall and process these memories in a safe environment (Ahern et al., 2000).


6.5.3. Depersonalization/Derealization Disorder

Depersonalization/derealization disorder symptoms generally occur for an extensive period before the individual seeks out treatment. Because of this, there is some evidence to support that the diagnosis alone is effective in reducing symptom intensity, as it also relieves the individual’s anxiety surrounding the baffling nature of the symptoms (Medford, Sierra, Baker, & David, 2005).

Due to the high comorbidity of depersonalization/derealization disorder with anxiety and depression, the goal of treatment is often alleviating these secondary mental health symptoms related to the depersonalization/derealization symptoms. While there has been some evidence to suggest treatment with an SSRI is effective in improving mood, the evidence for a combined treatment method of psychopharmacological and psychological treatment is even more compelling (Medford, Sierra, Baker, & David, 2005). The psychological treatment of preference is cognitive-behavioral therapy as it addresses the negative attributions and appraisals contributing to the depersonalization/derealization symptoms (Medford, Sierra, Baker, & David, 2005). By challenging these catastrophic attributions in response to stressful situations, the individual can reduce overall anxiety levels, which consequently reduces depersonalization/ derealization symptoms.


Key Takeaways

You should have learned the following in this section:

  • Treatment for dissociative identity disorder involves the integration of subpersonalities to the point of final fusion and takes several steps to achieve.
  • For some patients, this is not possible as they do not find final fusion to be a desirable outcome.
  • Instead, the clinician will work to achieve resolution or sufficient integration and coordination of the subpersonalities to allow the person to function independently.
  • For dissociative amnesia, hypnosis and phasic therapy are used, as well as barbiturates known as “truth serums.”
  • Finally, diagnosis alone is sometimes enough to reduce the intensity of symptoms related to depersonalization/derealization disorder and due to the high comorbidity with anxiety and depression, alleviation of these secondary symptoms is often the goal of treatment.


Section 6.5 Review Questions

  1. What is the treatment goal for dissociative identity disorder? How is it achieved?
  2. What are the treatment options for dissociative amnesia and depersonalization/depersonalization disorder?


Module Recap

In this module, we discussed the dissociative disorders of Dissociative Identity Disorder, Dissociative Amnesia, and Depersonalization/Derealization Disorder in terms of their clinical presentation, epidemiology, comorbidity, etiology, and treatment approaches.

3rd edition


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