Trauma: derealization is both an early psychological and biological marker of worse psychiatric outcomes


Results from the largest prospective study of its kind indicate that for individuals who experience trauma, the presence of dissociation – a profound feeling of detachment from one’s sense of self or surroundings – may indicate a high risk of later developing severe post-traumatic stress, depression, anxiety, physical pain, and social impairment.

The research, which was led by investigators at McLean Hospital, is published in the American Journal of Psychiatry.

“Dissociation may help someone cope in the aftermath of trauma by providing some psychological distance from the experience, but at a high cost – dissociation is often linked with more severe psychiatric symptoms,” said lead author Lauren A. M. Lebois, Ph.D., director of the Dissociative Disorders and Trauma Research Program at McLean Hospital and an assistant professor in psychiatry at Harvard Medical School.

“Despite this, dissociative symptoms remain under-studied and under-diagnosed due to a relative lack of understanding in medical and clinical practice.”

To provide insights, Lebois and her colleagues examined information from the Advancing Understanding of RecOvery afteR traumA (AURORA) Study. The data pertained to 1,464 adults treated at 22 different emergency departments across the United States who reported whether they experienced a severe type of dissociation called derealization.

Also,145 of the patients underwent brain imaging during an emotional task. Three months later, researchers collected follow-up reports of post-traumatic stress, depression, pain, anxiety symptoms, and functional impairment.

The research team found that patients who reported experiencing derealization tended to have higher levels of post-traumatic stress, anxiety, depression, pain, and functional impairment at the 3-month follow-up.

In addition, both self-reported survey results and brain imaging results that were indicative of derealization predicted worse post-traumatic stress symptoms at the follow-up exam—even after accounting for post-traumatic stress symptoms at the start of the study and histories of childhood trauma.

The results point to the importance of screening patients for dissociation-related symptoms following trauma to identify at-risk individuals who could benefit from early interventions.

The scientists discovered that derealization was linked with altered activity in certain brain regions detected through brain imaging.

“Therefore, persistent derealization is both an early psychological marker and a biological marker of worse psychiatric outcomes later, and its neural correlates in the brain may serve as potential future targets for treatments to prevent PTSD,” said senior author Kerry J. Ressler, MD, Ph.D., chief scientific officer at McLean Hospital and a professor in psychiatry at Harvard Medical School.

The investigators hope that their findings will increase awareness of these symptoms and their potential aftereffects.

“With any luck this will enable more clinicians to connect empathically and communicate thoughtfully with patients to help them understand their symptoms and available treatments,” said Lebois. “Sadly, omitting dissociation from the conversation increases patients’ vulnerability to more severe psychiatric problems following trauma.”

The research is an example of how patient care might be impacted by analyses of data from the AURORA Study—a major national initiative headquartered at the University of North Carolina that seeks to inform the development and testing of preventive and treatment interventions for individuals who have experienced traumatic events.

“These latest findings add to the growing list of discoveries from AURORA to help improve understanding about how to better prevent and treat adverse mental health outcomes after trauma,” said Samuel McLean, MD, the organizing principal investigator of the AURORA Study and a professor of anesthesiology, emergency medicine, and psychiatry at the University of North Carolina School of Medicine.

“Studies such as AURORA are critical because adverse post-traumatic mental health outcomes cause a tremendous global burden of suffering, and yet historically there have been very few large-scale longitudinal studies evaluating the underpinning neurobiology of these conditions.”

Acute Stress Disorder (ASD)

ASD and PTSD have several overlapping symptoms, but the key distinction between the two disorders is the longevity of those symptoms. An ASD diagnosis is considered from three days to one month following a traumatic event, which is referred to as the acute phase. After one month of trauma- and stress-related symptoms, ASD diagnoses no longer apply and psychiatric professionals instead assess for PTSD. ASD is still being studied as a predictor of PTSD, but current research indicates that about 50% of those with ASD later develop PTSD.

According to the DSM-5, diagnostic criteria of ASD includes:

  1. Exposure to actual or threatened death, serious injury, or sexual violation
  2. Presence of nine (or more) of the symptoms from any of the five categories of intrusion, negative mood, dissociation, avoidance, and arousal, beginning or worsening after the traumatic event(s) occurred *
  3. The duration of the disturbance (symptoms of Criterion B) is 3 days to 1 month after trauma exposure
  4. The disturbance is not attributable to the physiological effects of a substance (e.g., medication or alcohol) or other medical condition and is not better explained by brief psychotic disorder

*There are multiple diagnostic symptoms listed per category (5 categories, 14 total symptoms), examples of the symptoms by category are:

  • Intrusion: Recurrent, involuntary, and intrusive distressing memories of the traumatic event(s)
  • Negative mood: Persistent inability to experience positive emotions (e.g., inability to experience happiness, satisfaction, or loving feelings)
  • Dissociation: An altered sense of the reality of one’s surroundings or oneself
  • Avoidance: Efforts to avoid distressing memories, thoughts, or feelings about or closely associated with the traumatic event(s)
  • Arousal: Irritable behavior and angry outbursts (with little or no provocation) typically expressed as verbal or physical aggression toward people or objects

Post Traumatic Stress Disorder (PTSD)

Like ASD, PTSD is a psychiatric disorder that may occur in those who have directly or indirectly experienced a traumatic event, but PTSD only becomes diagnosable following the acute phase of trauma- and stress-related symptoms (after one month). While much of the symptoms that define ASD overlap with PTSD, the diagnostic criteria between the two disorders are different, which is further explained down below.

According to the DSM-5, diagnostic criteria of PTSD includes:

  1. Exposure to actual or threatened death, serious injury, or sexual violence
  2. Presence of one (or more) of the following intrusion symptoms associated with the traumatic event(s), beginning after the traumatic event(s) occurred *
  3. Persistent avoidance of stimuli associated with the traumatic event(s), beginning after the traumatic event(s) occurred *
  4. Negative alterations in cognitions and mood associated with the traumatic event(s), beginning or worsening after the traumatic event(s) occurred *
  5. Marked alterations in arousal and reactivity associated with the traumatic event(s), beginning or worsening after the traumatic event(s) occurred *
  6. Duration of the disturbance (Criteria B, C, D and E) is more than 1 month
  7. The disturbance causes clinically significant distress or impairment in social, occupational, or other important areas of functioning
  8. The disturbance is not attributable to the physiological effects of a substance (e.g., medication, alcohol) or another medical condition

*Similar to the DSM-5-defined symptom categories (intrusion, negative mood, etc.) listed in the diagnostic criteria for ASD, there are several symptoms per criterion B-E (20 total). Examples of those symptoms per criterion are identical to the ones listed above for ASD symptomatic categories.

PTSD Subtypes

In addition to the above diagnostic criteria for PTSD, the DSM-5 defined two new subtypes of PTSD: Preschool (or Pediatric) and Dissociative. The preschool subtype of PTSD is used only in the diagnosis of children younger than 6 years old. Instead of four symptom clusters (criteria B-E), there are three because avoidance and negative cognition (criteria C and D) were combined to form one category, which better reflects the lower prevalence rates of those symptoms in children. Of the symptoms listed within each category, developmentally-specific symptoms were also added to certain categories. Lastly, in addition to the child experiencing a traumatic event, a greater emphasis is placed on the impact a parent or caregiver who experienced a traumatic event can have on the child. Particular symptoms that are present in the PTSD preschool subtype are:

  • Recreating trauma in play/recurrent dreams of the trauma
  • Ongoing nightmares with or without recognizable content about the traumatic event
  • Avoiding activities or places that remind the child of the trauma
  • Exhibiting fear, guilt, and sadness, or withdrawing from friends and activities

The dissociative subtype of PTSD is used to more appropriately diagnose those who meet all the diagnostic criteria for PTSD, but also present with significantly predominant symptoms of depersonalization and derealization, as well as associated emotional detachment. The DSM-5-defined criteria for this subtype involve experiencing persistent or recurrent symptoms of one or both of the following, which may not be attributable to the effects of substances and/or other medical conditions.

  • Depersonalization: Persistent or recurrent experiences of feeling detached from, and as if one were an outside observer of, one’s mental processes or body (e.g., feeling as though one were in a dream; feeling a sense of unreality of self or body or of time moving slowly)
  • Derealization: Persistent or recurrent experiences of unreality of surroundings (e.g., the world around the individual is experienced as unreal, dreamlike, distant, or distorted).


Clearly, there is extensive overlap between the two disorders as they are both predicated upon experiencing a traumatic event and both defined by the symptom related to intrusion, negative mood/cognition, avoidance, arousal, and dissociation. Still, the disorders are distinguishable, such as in how the symptom categories are used as diagnostic criteria. In PTSD diagnosis, there are 20 total symptoms among the four symptom clusters and a person must meet at least one symptom within each criterion in order to be diagnosed. In ASD diagnosis, symptoms are not classified into different clusters, so a person can meet diagnosis by experiencing any 9 of the 14 total symptoms among the intrusion, intrusion, negative mood/cognition, avoidance, arousal, and dissociative symptom categories.

A second difference between the disorders is that PTSD diagnostic criteria includes non-fear based symptoms, such as risky or destructive behavior, overly negative thoughts and assumptions about oneself or the world, exaggerated blame of self or others for causing the trauma, negative affect, decreased interest in activities, feeling isolated, whereas ASD diagnostic criteria does not. Finally, a third distinction between the disorders is that PTSD separates dissociative symptoms of depersonalization and derealization from the four symptom clusters used to diagnose PTSD alone, and instead, uses them to specifically define the dissociative subtype of PTSD. In ASD diagnostic criteria, there are five symptom categories since dissociative symptoms of depersonalization and derealization are a part of the 14 total symptoms from which a person must meet 9 in order to be diagnosed with ASD

More information: Persistent Dissociation and Its Neural Correlates in Predicting Outcomes After Trauma Exposure, American Journal of Psychiatry (2022). DOI: 10.1176/appi.ajp.21090911


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