Fact Sheet III – Trauma Related Dissociation: An Introduction

What is Dissociation?

Dissociation is a process in which a person disconnects from their thoughts, feelings, memories, behaviors, physical sensations, or sense of identity. Dissociation is common among people seeking mental health treatment.

What Causes Dissociation?

Most health professionals believe dissociation is a way the mind copes with too much stress. Many people with a dissociative disorder have had a traumatic event during childhood, although dissociation can also occur with other types of trauma. This is called Trauma-Related Dissociation.

Trauma-Related Dissociation is sometimes described as a ‘mental escape’ when physical escape is not possible, or when a person is so emotionally overwhelmed that they cannot cope any longer. Sometimes dissociation is like ‘switching off’. Some survivors describe it as a way of saying ‘this isn’t happening to me’.

These reactions are usually temporary but, in cases of severe or repeated trauma, dissociation may last longer. This can be frightening and difficult to explain to others.

What are Symptoms of Dissociation?

Dissociation affects people in different ways. The different types of symptoms are described below.


Depersonalization refers to being disconnected from yourself or your body. Some people feel parts of their body are not real, disappear or change. Others feel numb, or much smaller than they really are. Some people have an ‘out of body’ experience – as if they are above or behind their body.

Depersonalization happens when people are distressed and is more common among people who were mistreated as children. Depersonalization helps a person cope by detaching.


Derealization is a sense of the external world not being real or being changed in some way. People might say that the world looks fake, flat, or far away. Sometimes people say the world looks as if they are watching a movie or as if they are in a dream or play acting on a stage. Sounds can also be distorted. Like depersonalization, this is a relatively common experience.

Derealization can help a person cope with trauma, by making the trauma seem less ‘real’. This creates a ‘mental distance’ to help them survive.

Dissociative Amnesia

Amnesia is the inability to recall important personal information. We all forget things sometimes (like not being able to remember where we put our keys), but amnesia involves serious memory problems for major events or parts of your life that most people can remember.

Lots of things can cause amnesia including substance abuse, head injury or disease. Dissociative Amnesia is a special term given to amnesia caused by not being able to fully integrate traumatic information, emotions, or memories.

The symptoms of Dissociative Amnesia vary, and can include:

  • memory gaps lasting from minutes to years;
  • forgetting part or all of a traumatic event;
  • forgetting things that remind you of trauma; and
  • having a ‘foggy’ memory of a trauma, or feeling like it ‘didn’t happen to you’.

People with Dissociative Amnesia can have amnesia in current life, even after the trauma has passed. Examples include:

  • not being able to recall a conversation or meeting with someone;
  • forgetting part of a day;
  • completing an important task (such as writing an essay or doing a job interview), but not remembering it;
  • Finding things that must belong to you, but having no memory of how you got them; or
  • Finding notes or drawings that you must have done, although you do not remember doing them.

Dissociative Amnesia is quite different to ‘normal forgetting’ and people with Dissociative Amnesia usually find it frightening and disorientating. They may be embarrassed and try to hide it from others. Sometimes people with Dissociative Amnesia feel ‘vague’ and ‘spaced out’. They may worry that they are ‘dumb’ or have brain damage.

However, people with Dissociative Amnesia are not less intelligent. Nor is the amnesia caused by lack of concentration. Dissociative Amnesia makes sense for survival. If a person cannot escape an ongoing trauma, being able to dissociate from the memory may help them to go to work or school or do other tasks of life.

However, when Dissociative Amnesia continues months or years after the trauma is over, it causes distress and disruption and needs treatment.

Identity confusion and identity alteration

Identity confusion is a term used when a person feels confused about ‘who they really are’. Their beliefs, opinions, tastes and thoughts may fluctuate a lot. While some identity confusion can be a normal part of life, particularly while growing up, traumatized people can experience this in a severe way, well into adult life.

Identity alteration is the sense of having a part or parts which feel very different from yourself. There may be a sense that some feelings, behaviors and memories do not belong to you. These may feel as if they come from or belong to someone else. An altered sense of identity can cause people to feel confused or unsure about ‘who they really are’.

Examples of identity alteration include:

  • having a sense of being more than one person;
  • feeling that you have ‘someone else’ inside;
  • hearing voices inside;
  • feeling that someone or something else ‘takes over’; or
  • confusion about your age or where you are.

Some people with identity alteration have obvious symptoms such as using different voice tones, language, or facial expressions. However, for most people the changes are subtle and hidden from others. In fact, people with dissociated identities often feel ashamed and distressed by their symptoms and try even harder to hide symptoms from others.

A person with identity alteration does not have ‘different people inside them’. It is more accurate to say that they have different ‘parts’ which make up the whole, single person. However, these parts are not integrated or accepted into a single ‘self’. This lack of integration causes the confusion and amnesia, and the sense of being controlled by someone or something else.

Dissociative disturbances of movement and sensation

Sometimes trauma-related dissociation causes physical symptoms which cannot be explained by a physical disease or disorder. These symptoms can include:

  • Unexplained loss of function after a trauma:
    • loss of senses such as sight, hearing, speech;
    • loss of movement or feeling in a part of the body, including paralysis or complete numbness; or
    • loss of skills such as temporary inability to remember how to drive a car or cook food.
  •  Unexplained intrusions in the body
    • involuntary movements or impulses that do not feel they are yours;
    • unexplained pain or other sensations; or
    • seizures which are not caused by a physical disorder like epilepsy.

Because these symptoms feel outside of the survivor’s control, they can cause fear and confusion. Often, they are misdiagnosed and people with such forms of dissociation may have a lot of medical treatment that does not help them. However once correctly diagnosed these symptoms can be treated by psychological methods. It is also important to realise that all these disorders can be improved or even resolved with effective treatments. For more information see Fact Sheet IV: What are the Dissociative Disorders? and Fact Sheet V: Getting Treatment for Complex Trauma and Dissociation.


Boon, S., Steele, K. & Van der Hart, O. (2011). Coping with Trauma-related Dissociation: Skills Training for Patients and Therapists, WW Norton and Co, New York.

Brand, B.L., Sar, V. Stavropoulos, P., Krüger, C., Korzekwa, M., Martínez-Taboas, A. & Middleton, W. (2016). Separating Fact from Fiction: An Empirical Examination of Six Myths About Dissociative Identity Disorder. Harvard Review of Psychiatry, 24(4): 257–270. doi:  10.1097/HRP.0000000000000100.

Brand, B.L., Lanius, R., Vermetten, E., Loewenstein, R.J. & Spiegel, D. (2012). Where Are We Going? An Update on Assessment, Treatment, and Neurobiological Research in Dissociative Disorders as We Move Toward the DSM-5, Journal of Trauma & Dissociation, 13:1, 9-31, DOI: 10.1080/15299732.2011.620687

Courtois, C.A. & Ford J.D. (2013) Treatment of Complex Trauma: A Sequenced, Relationship-Based Approach, Guilford Press, New York, p 9 – 27

Dell, P.F. (2009) The Phenomena of Pathological Dissociation. In P.F. Dell & J.A. O’Neil (Eds.) Dissociation and the Dissociative Disorders: DSM V and Beyond, Routledge, New York.

Dorahy, M.J., Brand, B.L., Şar, V., Krüger, C., Stavropoulos, P., Martínez-Taboas, A., Lewis-Fernández, R. & Middleton, W. (2014). Dissociative identity disorder:  An empirical overview. Australian & New Zealand Journal of Psychiatry, 48(5), 402–417, DOI: 10.1177/0004867414527523

Dorahy, M.J., Middleton, W., Seager, L., Williams, M. & Chambers, R. (2016). Child abuse and neglect in complex dissociative disorder, abuse-related chronic PTSD, and mixed psychiatric samples, Journal of Trauma & Dissociation, 17:2, 223-236, DOI: 10.1080/15299732.2015.1077916

Frewen, P. & Lanius, R. (2015). Healing the Traumatized Self: Consciousness, Neuroscience, Treatment. W.W. Norton & Co, New York.

Hunter, E. C., Sierra, M., & David, A. S. (2004). The epidemiology of depersonalisation and derealisation. A systematic review. Social Psychiatry and Psychiatric Epidemiology, 39(1), 9–18. doi:10.1007/s00127-004-0701-4

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

Lyssenko, L., Schmahl, C. Bockhacker, L., Vonderlin, R., Bohus, M. & Kleindienst, N. (2017). Dissociation in Psychiatric Disorders: A Meta-Analysis of Studies Using the Dissociative Experiences Scale. The American Journal of Psychiatry, 175. appiajp201717010025. 10.1176/appi.ajp.2017.17010025.

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.

Nijenhuis. E.R.S. (2004). Somatoform Dissociation: Phenomena, Measurement and Theoretical Issues, W. W. Norton and Co, New York

Ó Laoide, A., Egan, J. & Osborn, K. (2018). What was once essential, may become detrimental: The mediating role of depersonalization in the relationship between childhood emotional maltreatment and psychological distress in adults, Journal of Trauma & Dissociation,19:5, 514-534, DOI: 

Spiegel, D., Lewis-Fernández, R., Lanius, R., Vermetten, E., Simeon, D., & Friedman, M. (2013). Dissociative disorders in DSM-5. Annual Review of Clinical Psychology, 9, 299-326. http://dx.doi.org/10.1146/annurev-clinpsy-050212-185531

Steele, K., Boon, S. & Van der Hart, O. (2017). Treating Trauma-Related Dissociation: A Practical Integrative Approach, W.W. Norton & Co, New York.  

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