Dissociative Identity Disorder And Ptsd

  • Pei Yin Chai Bachelor of Science - BS, BSc(Hons) Neuroscience, The University of Manchester, England
  • Chloe Vilenstein Master's degree, Neuroscience, Ecole normale supérieure, Paris, France


Dissociative identity disorder (DID) is a personality disorder that is characterised by the presence of multiple personality states, while post-traumatic stress disorder (PTSD) is an anxiety disorder. Both DID and PTSD are associated with trauma exposure, especially during childhood.  

Understanding DID

Definition, symptoms, and diagnosis of DID

DID is actually one of the three main types of dissociative disorders, the other 2 types being depersonalisation-derealisation disorder and dissociative amnesia. DID is also previously known as ‘multiple personality disorder’.

DID is characterised by the presence of 2 or more personality states in an individual, also known as ‘alters’. Each DID patients have their own identity, which may present with distinct memories, thoughts, actions and experiences. Neutral memories and knowledge, though, are generally shared across the different alters.1

According to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), patients with DID experience 3 core dissociation symptoms:1

  • Identity alteration - the sense of being significantly different from another part of oneself.
  • Amnesia - the specific memory of one alter may not be known by the other alter(s).
  • Identity confusion - the feeling of confusion of one’s identity.

Although they are not diagnostic criteria of DID, depersonalisation and derealisation are 2 other symptoms experienced by some DID patients. Depersonalisation describes the feeling of watching yourself from a third-person perspective, while derealisation describes the feeling of familiar things and people suddenly appearing unfamiliar. 

Some DID patients may also experience hallucinations, in which they hear voices or see things that are not visible to others.1

Causes and risk factors, including trauma and abuse

DID patients often observe an onset of the symptoms around childhood, around the ages of 5 to10 years old.1 Childhood trauma, such as physical, sexual, and psychological abuse, natural disasters and war, remain the main cause of DID.

Overview of dissociation as a coping mechanism

To understand what DID is, we have to dissect what ‘dissociation’ means in this context. As the American Psychiatric Association described it, ‘dissociation’ is a normal process in which disconnection happens in our thoughts, memories, feelings, actions or sense of self, for example, when daydreaming. However, for DID patients, this dissociation likely evolved as a protective mechanism to psychologically detach from overwhelming traumatic experiences.2 Ozturk and Sar (2016) suggested that as the individual evaluates his or her traumatic experience through diverse perspectives, the self-perception through each perspective may aggregate as alter personalities.6 

Gillig (2009) explained that the presence of different alters allows the distressed alter to ‘retreat’ in stressful events, hence the ‘switching’ between different personalities. 

Understanding PTSD

Definition, symptoms, and diagnosis of PTSD

PTSD is an anxiety disorder that develops as a result of personal experience or witnessing unexpected, extreme, traumatic events. For example, survivors or witnesses of wars, natural disasters, sexual or physical assaults, severe accidents have higher likelihood of developing PTSD compared to the general population.3

The symptoms of PTSD can vary from person to person and are related to the nature of the traumatic events experienced. Some examples of PTSD symptoms include:3,5

  • Recurring distressing dreams related to the traumatic event
  • Dissociative reactions - e.g. having flashbacks of the traumatic event
  • Hypervigilance
  • Hostility and aggression
  • Paranoia
  • Anxiety
  • Hallucinations
  • Sleep problems
  • Avoidance of memories and cues related to the traumatic event
  • Somatisation - the extreme focus on physical symptoms such that it causes distress and disturbs day-to-day functioning.

Some PTSD patients may also have physical symptoms, such as sweating, trembling, nausea and pain.

There are 2 main types of PTSD, categorised by how long the symptoms persist. If symptoms last for less than 3 months, it is known as acute PTSD. Otherwise, it is known as chronic PTSD.

Causes and risk factors, including traumatic events

Despite being more common amongst people who have been exposed to extreme traumatic events, PTSD does not always develop in individuals who have encountered traumatic events. The likelihood of it happening is affected by the intensity and duration of the traumatic events, as well as the level of support received post-event.

People with the following risk factors are more vulnerable to PTSD:

  • Repeat exposure to trauma
  • Experiencing high levels of extra stress at the time of trauma exposure 
  • Experiencing mental health problems, such as anxiety and depression
  • Lack of social or family support

Overview of how trauma affects the brain

PTSD often causes impairment in memory and learning in patients. PTSD patients may suffer from deficits in separating and distinguishing similar experiences in the brain. Trauma also leads to the deficit of extinction learning of a fear response, which is the gradual decrease in fear response to a cue associated with the traumatic event. PTSD patients also tend to have shallower sleep.7

The link between DID and PTSD

Shared features and similarities

DID and PTSD are strongly associated with traumatic events. In fact, trauma is often an indicator of DID and PTSD. 

Both DID and PTSD patients experience some overlapping symptoms, such as dissociation and hallucination. It is common for PTSD patients to experience some degree of dissociation to cope with trauma. 

While there are similarities between DID and PTSD, it is important to note that PTSD patients don’t have alternate personalities or ‘alters’ as DID patients do.

How trauma can trigger the development of DID and PTSD

Brand and Lanius (2014) suggested that DID and PTSD are associated with difficulties in emotion regulation

When trauma-related emotions become too overwhelming, especially experienced during early childhood, an individual who’s less skilled at managing their emotions may develop dissociation symptoms to provide a form of psychological escape.2 DID most often develops in children who have suffered extreme traumatic events, such as long-term sexual, physical, or emotional abuse and disasters. Young children are still in the process of shaping their personal identities and may dissociate to cope with the traumatic events they experienced. Gillig (2009) suggested that young children who are at the age when they have imaginary companions may attribute their traumatic experiences to their imaginary companions as they deny associations with those experiences. These ‘imaginary companions’ may be the start of the development of their ‘alters’.1

While childhood trauma is also a strong indicator of PTSD, PTSD is more common in young adults because they are more likely to be exposed to precipitating traumatic events.3 

Co-occurrence of DID and PTSD

PTSD patients are often diagnosed along with other psychological disorders, including DID. People who have been exposed to trauma may experience dissociation in order to cope with the trauma. Wabnitz et al. (2013) suggested that if dissociation was a significant response after a person experiences a traumatic event, there is an increased likelihood that the individual will have a comparable dissociative reaction towards the memory of the traumatic event. The authors believe that recurring dissociation in response to traumatic memories may gradually become a personality change and result in DID in extreme cases.4

Diagnosis and treatment considerations

Challenges in diagnosing DID and PTSD

There aren't any diagnostic tests at the moment for DID and PTSD. Physicians often have to rely on interviews, reviewing personal health history and hypnosis, and investigating the symptoms that patients present. Since the onset of DID symptoms usually begin at around age 5-10, they easily go unnoticed or dismissed by adults as behavioural problems or learning difficulties. 

Treatment approaches for co-occurring DID and PTSD

The main treatment method for DID patients is cognitive behavioral therapy (CBT), in which therapists’ main goal is to teach DID patients appropriate ways to cope with distress instead ofswitching identities.1

CBT is also used for treating PTSD by helping patients recognise and challenge the negative thinking and beliefs that the same traumatic event would happen to them again. CBT is sometimes carried out along with exposure therapy in which patients re-enter the settings of the traumatic event under the guidance of the therapist to find ways to cope with it. Eye movement desensitisation and reprocessing (EMDR) therapy uses guided eye movements to help patients reconceptualise and process traumatic memories.

PTSD patients with anxiety or depression may also be prescribed anti-anxiety medications or antidepressants to help with their symptoms.


DID and PTSD are two psychological disorders that are heavily associated with trauma, especially when experienced during childhood. Both these disorders have distinctive as well as overlapping symptoms and can sometimes co-occur in an affected individual. Psychotherapy remains the main treatment method for both DID and PTSD, and the main goal is often to help patients reconcile and cope with their traumas. 


  1. Gillig PM. Dissociative identity disorder. Psychiatry (Edgmont) [Internet]. 2009 Mar [cited 2023 May 7];6(3):24–9. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2719457/ 
  2. Brand BL, Lanius RA. Chronic complex dissociative disorders and borderline personality disorder: disorders of emotion dysregulation? Borderline Personality Disorder and Emotion Dysregulation [Internet]. 2014 Oct 14 [cited 2023 May 7];1(1):13. Available from: https://doi.org/10.1186/2051-6673-1-13 
  3. Javidi H, Yadollahie M. Post-traumatic stress disorder. The International Journal of Occupational and Environmental Medicine. 2012;3(1):2–9. 
  4. Wabnitz P, Gast U, Catani C. Differences in trauma history and psychopathology between PTSD patients with and without co-occurring dissociative disorders. Eur J Psychotraumatol [Internet]. 2013 Nov 26 [cited 2023 May 19];4:10.3402/ejpt.v4i0.21452. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3842452/
  5. Treatment (US) C for SA. Exhibit 1.3-4, DSM-5 Diagnostic Criteria for PTSD [Internet]. 2014 [cited 2023 May 19]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK207191/ 
  6. Sar V, Ozturk E. Formation and functions of alter personalities in dissociative identity disorder: a theoretical and clinical elaboration. JPCPY [Internet]. 2016 Dec 7 [cited 2023 May 19];6(6). Available from: https://medcraveonline.com/JPCPY/formation-and-functions-of-alter-personalities-in-dissociative-identity-disorder-a-theoretical-and-clinical-elaboration.html 
  7. Pitman RK, Rasmusson AM, Koenen KC, Shin LM, Orr SP, Gilbertson MW, et al. Biological studies of posttraumatic stress disorder. Nat Rev Neurosci [Internet]. 2012 Nov [cited 2023 May 19];13(11):769–87. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4951157/ 
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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Pei Yin Chai

Bachelor of Science - BS, BSc(Hons) Neuroscience, The University of Manchester, England

Pei Yin (Joyce) is a recent neuroscience degree graduate from the University of Manchester. As an introvert, she often finds it easier to express herself in written words than in speech, that's when she began to have an interest in writing. She has 2 years of experience in content-creating, and has produced content ranging from scientific articles to educational comic and animation. She is currently working towards getting a career in medical writing or project management in the science communication field.

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