What Are Dissociative Disorders?

Dissociative disorders are a class of mental health disorders that cause a person to “lose time”, detaching themselves from themselves or their surroundings. This is done to shield themselves from a traumatic or high-stress event. 

There are three main types of dissociative disorders: depersonalisation-derealisation disorder, dissociative amnesia, and the most commonly portrayed dissociative disorder in media, dissociative identity disorder, where a character visibly switches between different identities. Dissociative disorders with symptoms lasting 12 months or longer are present in approximately 2% of the population.

This article goes into detail about the different types, causes, symptoms, and treatments for dissociative disorders.


Dissociative disorders are a class of mental health conditions. It involves a disruption of identity within a person. This often is associated with traumatic events that someone wants to forget or “shield” themselves from. This can happen by detaching oneself from their surroundings or their feelings.

According to the NHS, there are three main types of dissociative disorders.

  • Depersonalization-derealisationn disorder
  • Dissociative amnesia
  • Dissociative identity disorder

Causes of dissociative disorders

Someone can develop a dissociative disorder at any age, however symptoms most commonly present in early adulthood, but It is not well understood t causes dissociative disorders. Similar to other mental health conditions, the development of a dissociative disorder is thought to be related to traumatic events.1,2

  • The aftermath of trauma, embarrassment, or confusion about an event that occurred and the desire to hide away from what happened
  • High-stress situations

Examples of trauma includes:  

  • War
  • Physical, sexual, or emotional abuse
  • Disasters

The Diagnostic and Statistical Manual(DSM) is a handbook written and updated by the American Psychiatric Association to guide mental health professionals make accurate diagnoses of patients. It is a concise booklet of the definition, symptoms, statistics, and increased risk factors associated with each type of mental health condition.3 

DSM-5 places dissociative disorders next to trauma- and stressor-related disorders, which reflects the close relationship between these types of disorders.  Many people who are diagnosed with dissociative disorder are also diagnosed with post-traumatic stress disorder.

Signs and symptoms of dissociative disorders

Each type of dissociative disorder has its own set of symptoms that may be experienced. The DSM goes into detail about what you might experience with each disorder.3 In each disorder the DSM explicitly states that significant impairment in social, occupational, or personal functions is needed to be diagnosed.

Depersonalization-derealisation disorder

Someone with depersonalization-derealisation disorder can experience one or both types of dissociation that are included within this disorder: depersonalization and derealisation.

Depersonalization-Depersonalisation is the detachment from one’s mind or body. It can feel as if you are no one, having feelings but cannot feel them. It has been compared to having a “head full of cotton”. You can go through your life feeling as if you are a robot. Symptoms of this dissociation include:

  • Feeling emotionally or physically numb
  • Feeling that what you are experiencing is not your own

Derealizationn- is the detachment from one’s surroundings. It has often been referred to as if you are in a dream or fog. Things may appear to be colourless or lifeless around you. This type of dissociation is commonly accompanied by visual distortions such as:

  • Blurred vision
  • Seeing the world as two-dimensional (2D)
  • Widened or narrowed vision
  • Surroundings looking much sharper than normal
  • The distance or size of an object altered

How common is depersonalisation-derealisation disorder?

The DSM suggests that approximately 50% of the general population has experienced an episode of depersonalization or derealisation. Short periods of depersonalization or derealizationn symptoms are reported common in the general population. Symptoms lasting 12 months or longer are significantly reduced and a lifelong disorder only presents in approximately 2% of the population.3

Dissociative amnesia

Dissociative amnesia is a type of dissociation where the person is unable to remember events that they have experienced. This is different from normal forgetfulness that everyone may experience from time to time, such as forgetting why you walked into a room or where you put your keys.

There are three types of amnesia that one may experience:

  • Localized - This is the most common type of amnesia. This inability to remember an event or period, such as a single traumatic event
  • Selective - The inability to remember a specific part of an event, such as being able to recall some parts of a traumatic event but not all
  • Generalized - This is a very rare type of amnesia where someone forgets their identity as a whole and their life history. The person is unable to recall who they are, skills that they have learned and used throughout their life, or knowledge about the world they live in

People with dissociative amnesia are often unaware of their memory issues or the “lost time” until they are asked to recall events they cannot remember, have flashbacks that they cannot remember experiencing, or find physical evidence of events that occurred. It is rare for someone diagnosed to experience dissociative fugue, which is bewildered wandering.

It is important to note that dissociative amnesia is different from permanent amnesia from brain damage or toxicity.

How common is dissociative amnesia?

The DSM-5 states that among a small US adult study, there was 1.8% had dissociative amnesia that lasted at least 12 months.3

Dissociative identity disorder

Previously referred to as multiple personality disorder, someone diagnosed with dissociative identity disorder feels the presence of two or more distinct personalities and experiences recurring episodes of amnesia. 

Symptoms includes:

  • Discontinued sense of self
  • Gaps in everyday events, forgetting personal information, or traumatic events
  • Affect on behaviour, consciousness, or memory
  • Dissociative fugue (bewildered wandering)

These symptoms cause significant stress that affects the person’s ability to function in any social, personal, or professional setting.

The change in personality or experience of “possession” can occur in one of two ways:

Possessive dissociative identity disorder- is an uncontrollable and unwanted change of character. It is as if the person has been overtaken by a spirit, completely changing the way they act or speak. It is what most movies display when they have a character that has dissociative identity disorder, where they have an identity where they portray a child, the opposite gender, or other roles that change the way they act.

Non-possessive dissociative identity disorder- is a change that only the person can see within themselves. It can feel like their body is not their own, as if they have changed gender, age, or how their body feels. It can be as if they are hearing other voices or different streams of thoughts or emotions that they cannot control.

What triggers a change in “identity”?

Changes in identity can be triggered by 

several variables.

  • Being removed from a traumatizing situation
  • If the individual’s child reaches the same age as the individual when they were abused or traumatized
  • Other traumatic events
  • Death of their abuser

How common is dissociative identity disorder?

It is been reported that approximately 1.5% of the population worldwide has been diagnosed with this dissociative identity disorder.4

Management and treatment for dissociative disorders


To be diagnosed, your doctor will ask you questions relating to your family history and personal life. They will ask questions about your symptoms to rule out side effects from substance use, such as blacking out or a change in behaviour during intoxication, or from medication. Your GP may conduct neurological examinations to rule out brain damage.

Your general practitioner (GP) may refer you to a mental health professional or psychiatric clinic for a full diagnosis and treatment. Here they may run tests to determine gaps in your memory or experiences.

Approaches to dissociative disorders include:4

  • Establishing a safe and stable environment to reduce symptoms
  • Talking therapy to work through traumatic memories
  • Reintroducing a sense of identity

Increased risk factors

Someone with a dissociative disorder has a higher risk of having other mental health conditions, including:1,2

  • Post-traumatic stress disorder
  • Anxiety disorder
  • Depression
  • Eating disorders
  • Obsessive-compulsive disorder
  • Trouble sleeping
  • Suicidal ideation or attempts
  • Self-harm
  • Substance abuse, such as drugs or alcohol

According to the American Psychiatric Association, more than 70 percent of outpatients with dissociative identity disorder have attempted suicide.5 

If you or someone you know are feeling suicidal, there are people you can talk to who want to help. The NHS encourages you to call the Samaritan's free 24-hour support service (116 123) or contact NHS 111 phone line.


Talking therapy, also known as psychotherapy, is often recommended for mental health disorders. The two most commonly used psychotherapy for dissociative disorders are cognitive behavioural and dialectical behavioural therapy. This therapy will help you understand your trauma and work towards introducing a sense of identity with healthy habits.


There is no medication to specifically treat dissociation, however, your doctor may prescribe medication to treat related symptoms. An example is antidepressants to treat anxiety and depression. PTSD medication, mood stabilizers


Dissociative disorders are a category of mental health disorders. They are most commonly thought to be caused by a trauma that the person is trying to shield themselves from, therefore detaching themselves from the situation and their feelings or surroundings. 

They are classified into three main disorders: depersonalization-derealisation, dissociative amnesia, and dissociative identity disorder. There is no cure for dissociative disorders and treatment includes treating symptoms such as anxiety or depression. Each type of dissociative disorder has its own set of symptoms but all can benefit from talking therapy to understand their feelings and trauma, working towards reintroducing a sense of identity.


  1. Dissociative Identity Disorder - Psychiatric Disorders [Internet]. MSD Manual Professional Edition. [cited 2023 Feb 23]. Available from: https://www.msdmanuals.com/en-gb/professional/psychiatric-disorders/dissociative-disorders/dissociative-identity-disorder
  2. Dissociative disorders [Internet]. nhs.uk. 2021 [cited 2023 Feb 19]. Available from: https://www.nhs.uk/mental-health/conditions/dissociative-disorders/
  3. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders (DSM-5®) [Internet]. Washington, UNITED STATES: American Psychiatric Publishing; 2013 [cited 2023 Feb 24]. Available from: http://ebookcentral.proquest.com/lib/imperial/detail.action?docID=1811753
  4. Mitra P, Jain A. Dissociative Identity Disorder [Internet]. StatPearls [Internet]. StatPearls Publishing; 2022 [cited 2023 Feb 21]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK568768/
  5. What Are Dissociative Disorders? [Internet]. [cited 2023 Feb 24]. Available from: https://www.psychiatry.org:443/patients-families/dissociative-disorders/what-are-dissociative-disorders
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Sara Nakanishi

Master’s of Science - Genes, Drugs, and Stem Cells - Novel Therapies, Imperial College London

Bachelor of Science - Biochemistry/Chemistry, University of California San Diego

Hello! My name is Sara and I have a diverse background in science, particularly in biochemistry and therapeutics. I am extremely passionate about heart health and mental illness. My goal is to break down complex scientific topics to share with those with non-scientific backgrounds so they can be well-informed about their conditions and ways to live a balanced life. I believe that education and awareness are key to leading a healthy lifestyle and I hope to inspire others through my writing.

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