Research on posttraumatic stress disorder (PTSD) has shown that those who show signs of dissociation at the time of a traumatic event (known as "peritraumatic dissociation") are more likely to experience acute and chronic PTSD. Until now, there had been little research about who is at risk for peritraumatic dissociation. The authors of a new study set out to examine the relationship between peritraumatic dissociation and prior major depression, prior PTSD, prior trauma, and prior peritraumatic dissociation.

Researchers recruited a group of 122 (64 male, 58 female) motor vehicle accident (MVA) subjects. The researchers used two evaluative tools: the Structured Clinical Interview for DSM-III-R (SCID), and the Peritraumatic Experiences Questionnaire-Rater Version (PDEQ-RV). Subjects were recruited either from the regional trauma center of a major suburban hospital, or through local police reports of severe MVAs. The average age of the subjects at the time of the MVA was 35.6 years. Most subjects were single (62.3%), white (76.2%), reported an income of more than $20,000 per year (64.5%), and had at least some college education (72%). All subjects had been either drivers or passengers in serious MVAs that had involved another passenger car, truck, or motorcycle.

Subjects were evaluated at one-month post-accident using the DSM-III-R (SCID) including the PTSD supplement. This test assessed both lifetime and current PTSD. Additionally the PDEQ-RV was administered to measure both past and present (MVA-associated) peritraumatic dissociation.

The authors found no relationship between present MVA-related peritraumatic dissociation and prior trauma, prior peritraumatic dissociation, or prior PTSD. The authors did find an important link between peritraumatic dissociation and prior major depression. Other research has shown a relationship between peritraumatic dissociation and subsequent depression, but this is the first study to report past depression as a risk factor for peritraumatic dissociation. Since PTSD is frequently comorbid with major depression, the authors theorize that peritraumatic dissociation may be part of the neurobiological link between major depression and PTSD. The authors suggest, "If peritraumatic dissociative symptoms are part of the neurobiological mechanisms underlying major depression, treatment of the subgroup of PTSD patients who report peritraumatic dissociation with antidepressants may be helpful in ameliorating or preventing PTSD or its often comorbid major depression."

It is unclear if severity of trauma is a good predictor of peritraumatic dissociation. Researchers in this study found that passenger injury was a risk factor for peritraumatic dissociation, which might suggest that severity of trauma is a risk factor. The authors recommend that future research on peritraumatic dissociation and passenger injury should look at when and how the subject learned of the passenger injury.

The authors sum up their findings on MVAs and peritraumatic dissociation:

"MVAs are common and often result in PTSD. Because peritraumatic dissociation increases the risk of both acute and chronic PTSD, it is important to understand its neurobiological and psychological mechanisms. In addition, peritraumatic dissociation can be rapidly and easily assessed in MVA victims and may offer the clinician the opportunity for early psychological and pharmacological intervention with a high-risk group."

Fullerton CS, Ursano RJ, Epstein RS, Crowley B, Vance KL, Kao T, Baum A. peritraumatic Dissociation Following Motor Vehicle Accidents: Relationship to Prior Trauma and Prior Major Depression. The Journal of Nervous and Mental Disease. 2000;188(5):267-272.

Motor Vehicle Accidents and Peritraumatic Dissociation