Fact Sheet IV – What are the Dissociative Disorders?

Most mental health professionals consider that Dissociative Disorders are caused by severe trauma, usually in early childhood. You may find it helpful to also read Fact Sheet I: Trauma and Complex Trauma: An Overview and Fact Sheet II: Post-Traumatic Stress Disorders.

Mental health professionals use diagnoses to help them understand and communicate about mental health symptoms. There are several different ways of labelling dissociative disorders, so the names of disorders might differ between countries. However, they all describe the same groups of symptoms.

While diagnoses can be helpful, they also have limitations. Some survivors feel diagnoses do not fully capture their symptoms or are pathologizing. Despite these issues, it can be helpful for survivors to have an understanding of the most common diagnostic labels used.

Depersonalization/Derealization Disorder

People with Depersonalization/Derealization Disorder experience one or both of the following:

  • Depersonalization – Feeling detached from their mind or body in a significant way. This can include feeling as if parts of their body are detached, or as if they are outside their body and watching themselves.
  • Derealization – Feeling that the outside world is not real, less real, distant or changed in some way.

A person with this disorder is aware of reality and that their experience is unusual. They often find the symptoms distressing or confusing. However, they can hide the symptoms and appear unreactive or unemotional. This can lead to people with this disorder to miss out on treatment and support.

A diagnosis is made when the symptoms are not better explained by another disorder and do not only occur when the client is under the influence of a drug or alcohol.

Dissociative Amnesia

A Diagnosis of Dissociative Amnesia is made when people meet the following criteria:

  • Not being able to recall information about themselves that is more severe than ‘normal forgetfulness’. This amnesia is usually related to a traumatic or stressful event and is usually just for a certain time-period, or for specific events. In some rare cases people experience a complete loss of identity and life history.
  • Experience distress and impairment due to the amnesia.
  • The amnesia is not explained by the use of alcohol or drugs, another medical condition or another mental health condition (for example, PTSD or Dissociative Identity Disorder).

Dissociative Amnesia is associated with childhood trauma, but can occur after adult traumas. People with Dissociative Amnesia may try to hide or minimize their memory loss. Sometimes people with Dissociative Amnesia are later found to have another condition such as Dissociative Identity Disorder.

Dissociative Identity Disorder

Dissociative Identity Disorder (DID) was previously called Multiple Personality Disorder.

The criteria for DID include:

  • The existence of two or more distinct, separate identities. These are sometimes called ‘parts’ or ‘aspects of self’. The separate identities have different behaviors, memory and ways of thinking. Changes between identities cause confusion and disruption in awareness and ‘sense of self’. Sometimes others will observe changes. However, such symptoms can also be hidden from others. It is uncommon for a person with DID to feel that they have control over ‘switching’ between identities (although this becomes more possible with extensive therapy).
  • Recurring gaps in memory about everyday events, personal information and/or past traumatic events. This amnesia is very different from ‘ordinary forgetting.’
  • The symptoms cause significant distress or problems with everyday life such as interfering with relationships, self-care, work or study.

These symptoms vary between individuals with DID (just like other mental health conditions have individual differences). For example, some people have obvious signs of identity change, but others have very few outward signs. Some people find that having DID has a severe impact on their lives, while others find the impact is more manageable.

It is likely that a therapist will take a lot of time and care in diagnosing DID, just as with other trauma-related disorders. The therapist will listen to you report your experiences, as well as observe you to note symptoms of dissociation. The therapist will also make sure that these symptoms are not caused by, or better explained by some other condition, such as alcohol or drug use, a cultural/religious experience, or other problems.

Other Specified Dissociative Disorder (OSDD)

Therapists may make this diagnosis when dissociative symptoms are causing distress and impairment, but do not meet the full criteria for another dissociative disorder. As with DID a therapist will likely take quite some time to make this diagnosis, carefully listening to your symptoms and observing you in assessment.

There are four different categories used for OSDD. These can also be called ‘sub-types’ or ‘specifiers’. The four categories are:

  1. Having chronic dissociative symptoms such as identity alteration, but the alteration and separation between identities is not as severe as in DID. There may be identity disturbance, but not the presence of clearly separated parts or amnesia.
  2. Having identity disturbance due to a long period of ‘intense coercive control and persuasion’. This includes the type of ‘brainwashing’ or control that can occur in cults, during political imprisonment or during torture.  In such cases people may begin to be confused about or question their identity.
  3. Having acute dissociative reactions to stressful events. These typically last less than a month and can last for hours or days at a time. These reactions can include depersonalisation, small periods of amnesia, and changes in sensory-motor functioning.
  4. Experiencing Dissociative Trance. The person experiences periods of time where they lose awareness of the outer world and become unresponsive. This is not something the person can control. While in a trance the person may have temporary paralysis or loss of consciousness. A diagnosis is only made when this trance occurs outside of religious/cultural practice and when not under the influence of drugs. In some parts of the world this might be diagnosed as ‘Trance Disorder’.
Partial Dissociative Identity Disorder

This is a diagnostic term that is more recent, and currently more likely to be used outside of North America. It is similar to OSDD (Type 1) described above.

In the case of Partial DID the person still experiences a disruption of their identity, like in DID, but there is a ‘dominant’ personality which is usually at the front. Intrusions from other parts are infrequent and irregular, perhaps only happening during a particularly distressing or emotional experience.

To make this diagnosis your clinician will spend time listening to you and assessing your symptoms. They will make the diagnosis if they feel sure that the symptoms are not better explained by another mental, behavioural or medical condition, nor due to the effects of alcohol and drugs. The symptoms also need to result in significant impairment in important areas of everyday life such as relationships, self care, work or study.

Conversion Disorder (Also Known as Functional Neurological Symptom Disorder or Dissociative Neurological Symptom Disorder

Sometimes people with trauma related dissociation can experience significant and unexpected changes in movement, function or sensation that are not part of another trauma-related disorder such as Complex PTSD or DID. Many clinicians and researchers consider this a type of dissociation that is expressed through the body. For this reason, this diagnosis is also discussed here.

People with this disorder experience changes in motor (movement) or sensory function. These changes cannot be explained by other neurological, medical or psychiatric conditions.

The changes can include:

  • weakness or paralysis in part of the body;
  • abnormal movement (e.g. tremors, or other changes in movement);
  • difficulty swallowing;
  • changes to speech (e.g. stuttering, slurring, inability to speak);
  • changes to, or loss of sense of smell, sight, taste or hearing; or
  • sudden attacks or seizures.

These changes feel unwanted and intrusive to the person with this disorder. They cause distress and/or impairment to everyday life activity.

Diagnosing these conditions can be challenging, as other disorders have to be ‘ruled out’ first. Your clinician will usually listen to you describe your symptoms and also observe you for some time before making this diagnosis. You will also need to be referred to other medical professionals to make sure that you do not have a medical disorder causing the symptoms. This can be distressing and frustrating, but is an important part of the process.

Receiving a Diagnosis of a Dissociative Disorder

If you have been diagnosed with a dissociative disorder, it is important to realize that this disorder is a label given to describe some of the symptoms you experience. It is not a label to describe all of who you are. It is also important to realize that, even within diagnostic categories, there is considerable individual variation and all treatment will still need to be personalized.

Receiving a diagnosis may be confusing and frightening, particularly if you have already had other mental health diagnoses in the past. Sometimes people with dissociative disorders are subject to negative and critical portrayals in the media, or face judgement and disbelief from health professionals. This can compound distress and shame for people with such disorders. However, other people find the diagnosis is a relief as they have an explanation for their symptoms. A correct diagnosis can also help you find the best treatment for your condition. The symptoms of Dissociative Disorders can be improved or resolved through effective treatments.

Whatever your feelings and reactions, it is important to discuss them with a caring and supportive therapist. You may also find it helpful to read Fact Sheet V: Getting Treatment for Complex Trauma and Dissociation


APA (2013). The diagnostic and statistical manual of mental disorders (5th Ed.) Washington D.C. Author.

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International Society for the Study of Trauma and Dissociation (2011): Guidelines for Treating Dissociative Identity Disorder in Adults, Third Revision, Journal of Trauma & Dissociation,12:2, 115-187, doi:10.1080/15299732.2011.537247

Nijenhuis. E.R.S. (2009). Somatoform Dissociation and Somatoform Dissociative Disorders. In P.F. Dell & J.A. O’Neil (Eds.). Dissociation and the Dissociative Disorders: DSM V and Beyond, Routledge, New York.

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Vonderlin R., Kleindienst N., Alpers G.W., Bohus M., Lyssenko L., Schmahl, C. (2018). Dissociation in victims of childhood abuse or neglect: a meta-analytic review. Psychological Medicine 48, 2467–2476. https://doi.org/10.1017/S0033291718000740

World Health Organization. (2018). International statistical classification of diseases and related health problems (11th Revision). Retrieved from https://icd.who.int/browse11/l-m/en

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