Psychophysiological investigations of posttraumatic stress disorder imagery

Physiological responses to self-generated imagery of past traumatic combat experiences were assessed in medication-free Vietnam combat veterans, classified on the basis of DSM-III-R (American Psychiatric Association 1987) criteria into posttraumatic stress disorder (PTSD, n = 25), non-PTSD anxiety disorder (Anxious, n = 7), or no-mental-disorder (Healthy, n = 15) groups. "Scripts" describing each subject's combat experiences were read to him in the laboratory, and he was instructed to imagine the events the scripts portrayed, while heart rate, skin conductance, and frontalis electromyogram (EMG) were recorded. PTSD subjects' responses to their combat imagery were significantly higher than those of both control groups. A discriminant analysis identified 64 percent of PTSD subjects as physiological responders, and 100 percent of Anxious and 94 percent of Healthy subjects as nonresponders. A pilot study of imaginal flooding in three PTSD and two Healthy pilot subjects suggested that more prolonged, therapist-assisted imagery might increase the sensitivity of psychophysiological measures to PTSD, and that motor and endocrinological measures might also be of value in characterizing the disorder.