Concordance between physiological arousal and subjective distress among Vietnam combat veterans undergoing challenge testing for PTSD.

This study examined concordance between physiological arousal and subjective distress during a laboratory challenge task. Data were collected during the multisite VA Cooperative Study 334 in the early 1990s examining psychophysiological arousal among combat-exposed Vietnam veterans with (n = 775) and without (n = 369) posttraumatic stress disorder (PTSD). Study participants were presented with 6 standardized neutral scenes and 6 standardized combat scenes. Participants provided a subjective rating of distress after each slide. During the presentation, levels of heart rate (HR) and skin conductance (SC) were recorded. Using linear mixed effects modeling, both HR level and SC level exhibited significant positive associations with subjective distress ratings (pr = .33, p < .001 and pr = .19, p < .001, respectively). Individuals with PTSD demonstrated greater concordance between their distress ratings and SC level during exposure to combat slides than participants without PTSD (pr = .28, p < .001 vs. pr = .18, p < .001). Although a significant association was found between subjective distress and HR reactivity and SC reactivity, these findings were not moderated by PTSD status. The results of these analyses suggest that patients' reports of distress during exposure-based treatments might serve as approximate measures of actual physiological arousal.