Does memory of a traumatic event increase the risk for posttraumatic stress disorder in patients with traumatic brain injury? A prospective study

Objective: The present study examined prospectively the relationship between memory of the traumatic event and subsequent development of posttraumatic stress disorder ( PTSD). More specifically, the aims of this study were to 1) investigate the possibility that lack of memory of the traumatic event might be a protective factor; 2) assess whether memory of the traumatic event equally affects the three symptom clusters of PTSD: reexperiencing, avoidance, and hyperarousal; and 3) explore the predictive value of memory of the traumatic event for the development of subsequent PTSD in the immediate aftermath of the event. Method: One hundred twenty subjects with mild traumatic brain injury who were hospitalized for observation were assessed immediately after the trauma and followed up 1 week, 3 months, and 6 months later. All participants underwent psychiatric evaluation and self-assessment of their memory of the traumatic event. Results: Overall, 17 (14%) of the participants met full criteria for PTSD at 6 months. Subjects with memory of the traumatic event were significantly more likely to develop PTSD than those without memory of the traumatic event; the difference between the groups resulted primarily from the reexperiencing cluster. Logistic regression analysis revealed that memory of the traumatic event within the first 24 hours is a strong predictor of PTSD 6 months after the event. Conclusions: Our study indicated that memory of a traumatic event is a strong predictor and a potential risk factor for subsequent development of PTSD. Future studies are needed to show whether these findings can be generalized to other traumatic conditions.