The physiological response to trauma-related stimuli of up to one third of participants with posttraumatic stress disorder (PTSD) cannot be discriminated from that of controls. Psychophysiological measures (heart rate and blood pressure) of 22 PTSD and 23 control civilian participants, all exposed to missile attacks during the Gulf War, were recorded while listening to five scripts. The physiological response of PTSD subjects with high image control (IC) was lower than that of PTSD participants with low IC and similar to that of non-PTSD subjects. The physiological response poorly discriminated high IC PTSD participants from controls, but was successful in discriminating low IC PTSD subjects from controls with 91% specificity and 92% sensitivity. Image control is proposed as a function influencing physiological response in PTSD.