A Study of Trauma Memory in Survivors of the 9/11 Attacks Using the Deese-Roediger-McDermott (DRM) Memory Paradigm

BACKGROUND. PTSD has been found to be associated with abnormalities in memory function. This relationship has not previously been studied with the Deese-Roediger-McDermott (DRM) paradigm in disaster-exposed populations. The DRM paradigm uses semantically related and unrelated intrusions in an immediate test of recited word lists. It was hypothesized that PTSD would be associated with false alarms to critical lures in the DRM paradigm. METHODS. Approximately three years after the 9/11 attacks, a volunteer sample (N=379) was recruited from members of eight participating agencies (three agencies in the WTC towers and one nearby agency, three agencies that provided 9/11 disaster recovery services, and an airline that lost personnel and property in the attacks). This sample was assessed for individual disaster experience and related psychiatric status using a fully structured diagnostic interview to assess full DSM-IV-TR criteria. At the end of the interview, the DRM paradigm was administered to test participants' recognition of words. RESULTS. No associations were found between PTSD or other psychopathology and DRM memory variables. The only predictor of false alarms to critical lures was direct exposure to 9/11 trauma, which was not associated with correct identification of recited words or with false alarms to unrelated lures. DISCUSSION. The study's hypothesis that PTSD would be associated with false alarms to critical lures was not supported. The finding that direct 9/11 endangerment was associated with critical lures was unexpected. The results suggest that neural processing of trauma exposure may involve associative processes of overgeneralization in cognitive processing coupled with insufficient inhibition of responses to associated but harmless stimuli. The findings of this study also support the importance of differentiating psychopathology such as PTSD from normal physiologic fight-or-flight responses to trauma in studies of memory and neurobiological investigations of trauma and its effects in future research.