a1 Department of Psychology, Institute of Psychiatry, King's College London, UK
Background Intrusive re-experiencing in post-traumatic stress disorder (PTSD) comprises distressing sensory impressions from the trauma that seem to occur ‘out of the blue’. A key question is how intrusions are triggered. One possibility is that PTSD is characterized by a processing advantage for stimuli that resemble those that accompanied the trauma, which would lead to increased detection of such cues in the environment.
Method We used a blurred picture identification task in a cross-sectional (n=99) and a prospective study (n=221) of trauma survivors.
Results Participants with acute stress disorder (ASD) or PTSD, but not trauma survivors without these disorders, identified trauma-related pictures, but not general threat pictures, better than neutral pictures. There were no group differences in the rate of trauma-related answers to other picture categories. The relative processing advantage for trauma-related pictures correlated with re-experiencing and dissociation, and predicted PTSD at follow-up.
Conclusions A perceptual processing bias for trauma-related stimuli may contribute to the involuntary triggering of intrusive trauma memories in PTSD.
(Received November 26 2010)
(Revised May 17 2011)
(Accepted May 20 2011)
(Online publication June 21 2011)
c1 Address for correspondence: Professor A. Ehlers, Department of Psychology (PO77), Institute of Psychiatry, King's College London, De Crespigny Park, London SE5 8AF, UK. (Email: firstname.lastname@example.org)