We know a great deal about what happens to people in the aftermath of trauma, the flashbacks, the hypervigilance, the avoidance, the dysregulated emotions, the disrupted sleep. But one of the most important predictors of long-term outcomes is something that happens much earlier: what occurs in the mind and body at the moment the traumatic event takes place.
Researchers call this peritraumatic dissociation, dissociation occurring during or immediately after a traumatic event. And the evidence suggests it may be the single most important predictor of whether someone goes on to develop PTSD.
In 1994, Marmar and colleagues developed the Peritraumatic Dissociative Experiences Questionnaire (PDEQ), a nine-item instrument designed to measure dissociative experiences at the time of traumatic exposure. Using this tool in a study of 251 male Vietnam Theater Veterans, they found a clear and significant relationship: the greater the dissociation during traumatic stress exposure, the greater the likelihood of meeting criteria for PTSD (Marmar et al., 1994).
This finding was not isolated. Weiss, Marmar, and colleagues (1995) replicated it in a sample of 367 emergency services personnel exposed to traumatic events on the job, individuals whose professional training did not protect them from the psychological consequences of peritraumatic dissociation. The same relationship was confirmed in a study of adults who lived near the epicenter of the 1994 Los Angeles Northridge earthquake, a civilian population with no special trauma training.
Even more striking was a study by Morgan and colleagues (2001), which examined healthy soldiers during controlled, acute stress exposure in United States Army survival training. All of the soldiers experienced dissociative symptoms in response to high stress, and those symptoms were significantly associated with how everyone had responded to a previous traumatic event. In other words, peritraumatic dissociation appears to be not just a response to the current event, but a reflection of how a person’s nervous system has been shaped by prior trauma.
Why does what happens in the moment matter so much? The answer lies in memory. During a traumatic event, the normal process of encoding and integrating experience is disrupted. Instead of being stored as a coherent narrative, something that happened, with a beginning, middle, and end, traumatic memory becomes fragmented: sensory impressions, emotional states, and body sensations that are not fully integrated into personal history. This fragmentation is the foundation of dissociative symptoms and, ultimately, of PTSD.
Janet, one of the earliest theorists of dissociation, described this process in the nineteenth century: traumatic experiences that cannot be integrated into personal narrative do not simply disappear. They persist, breaking back into consciousness as terrifying perceptions, somatic experiences, flashbacks, obsessive ruminations, and behavioral re-enactments.
Understanding peritraumatic dissociation matters clinically because it points toward the importance of early intervention. The longer dissociative symptoms go unaddressed following a traumatic event, the more entrenched they become. Research consistently shows that addressing dissociation early, rather than waiting until PTSD is well-established, improves outcomes significantly.
At Let’s Talk Psychological Wellness, we provide trauma-informed assessment and treatment for individuals who have experienced traumatic events, whether recent or in the distant past. If you have been through something difficult and are noticing symptoms you cannot quite explain, early support can make a meaningful difference.
References
Marmar, C. R., Weiss, D. S., Schlenger, W. E., Fairbank, J. A., Jordan, B. K., Kulka, R. A., & Hough, R. L. (1994). Peritraumatic dissociation and posttraumatic stress in male Vietnam theater veterans. American Journal of Psychiatry, 151(6), 902–907.
Morgan, C. A., Hazlett, G., Wang, S., Richardson, E. G., Schnurr, P., & Southwick, S. M. (2001). Symptoms of dissociation in humans experiencing acute, uncontrollable stress. American Journal of Psychiatry, 158(8), 1239–1247.
Weiss, D. S., Marmar, C. R., Metzler, T. J., & Ronfeldt, H. M. (1995). Predicting symptomatic distress in emergency services personnel. Journal of Consulting and Clinical Psychology, 63(3), 361–368.
Caldeira, N. A. (2004). Dissociation and Treatment Outcome in Urban Women with Comorbid PTSD and Substance Use Disorders. ProQuest, April 2004. UMI Dissertation Services Microform 3126239.