Amnesia, traumatic brain injury, and posttraumatic stress disorder: a methodological inquiry.

This study explored the relationship between mild traumatic brain injury (MTBI), amnesia, and posttraumatic stress disorder (PTSD). MTBI status and amnesia for the event were assessed in 307 consecutive admissions to a Level 1 Trauma Center. Amnesia did not always occur concurrently with MTBI: 18% of those with MTBI had full recall and over half had partial recall of the event. Just over 10% of participants developed PTSD by 12 months post-injury, with prevalence comparable across MTBI and non-MTBI groups. Non-significant differences in incidence of PTSD were apparent between those with full recall (9%), partial recall (14%) and no recall (7%). These data highlight the fact that PTSD may develop following trauma despite amnesia for the event, and illustrate the importance in both clinical and research settings of carefully examining the extent of amnesia.