This report describes a husband and wife with acute posttraumatic stress disorder (PTSD) who exhibited different subjective, psychophysiological, and neurobiological responses to traumatic script-driven imagery that caused them to reexperience their traumas. The couple, who had been trapped in their car during a serious motor vehicle accident, was assessed for responses to script-driven traumatic imagery with a heart rate monitor and functional magnetic resonance imaging (fMRI). The accident involved more than 100 vehicles, multiple deaths, and serious injuries. After they crashed into a car in front of them, both subjects were trapped in their car for several minutes, during which they witnessed a child burn to death and feared that they too would die. Neither sustained physical injuries. Both reported reliving their peritraumatic responses. The man experienced intense anxiety, arousal, and escape-focused cognitions; his heart rate increased 13 bpm from baseline. Blood-oxygenation-level-dependent (BOLD) signal increases were found in his anterior frontal, anterior cingulate, superior and medial temporal, thalamic, parietal, and occipital brain regions. In contrast, the woman reported being extremely "numb" and "frozen," had no heart rate change, and had BOLD signal increases only in occipital regions. This report highlights the importance of individual differences in subjective and biological characteristics of posttraumatic remembrances, particularly those related to peritraumatic dissociation and numbing.

Both subjects were assessed 4 weeks after the accident with the Structured Clinical Interview for DSM-IV +(1), the Clinician-Administered PTSD Scale +(2), the Peritraumatic Dissociative Experiences Scale +(3), and the Dissociative Experiences Scale +(4). Both met criteria for acute stress disorder, with score on the Clinician-Administered PTSD Scale of 74 and 86 for the husband and wife, respectively. The wife experienced much greater peritraumatic dissociation and had a score on the Peritraumatic Dissociative Experiences Scale of 22 versus her husband’s score of 1; however, both had low trait dissociation, with scores on the Dissociative Experiences Scale of less than 3. Responses to script-driven traumatic imagery were measured with 4-T fMRI, a heart rate monitor, and self-report measures (for detailed methods, see references +5–+8).

In terms of subjective experiences, heart rate responses, and patterns of neural activation, these two survivors of the same traumatic event exhibited two distinct yet internally coherent peritraumatic and subsequent pathological responses to traumatic reminders. The husband’s reports of cognitive and behavioral activation along with physiological arousal are consistent with observed increases in anterior frontal, thalamic, and amygdala activations and heart rate. His response also resembles the traditionally described hyperarousal response to script-driven imagery in PTSD +(9). In contrast, the woman’s "numb" and "frozen" subjective experiences, lack of an increase in heart rate, and very different pattern of neural activations, despite having a severe case of acute and subsequent PTSD, add to an emerging literature on individual differences in posttraumatic pathophysiology +(10–+14).

In summary, our fMRI results demonstrate that PTSD patients can have very different responses, both subjectively and biologically, while reexperiencing traumatic events. They also indicate the need for more research on dissociative and numbing responses associated with an absence of increased cardiovascular arousal as distinct types of PTSD reexperiencing symptoms. Finally, our fMRI findings suggest that different neuronal mechanisms may generate these different reactions to traumatic reminders.

Received July 31, 2002; revision received Dec. 17, 2002; accepted Dec. 19, 2002. From the Department of Psychiatry, Medical Biophysics, University of Western Ontario, London, Ontario, Canada; the Department of Psychiatry, Boston University School of Medicine, Boston; and the Robarts Research Institute, London, Ontario, Canada. Address reprint requests to Dr. Lanius, Department of Psychiatry, London Health Sciences Centre, 339 Windermere Rd., PO Box 5339, London, ON, Canada N6A 5A5; ruth.lanius@lhsc.on.ca (e-mail). Supported by a grant from the Canadian Institutes of Health Research and the Ontario Mental Health Foundation.