Psychophysiologic responsivity in posttraumatic stress disorder: Generalized hyperresponsiveness versus trauma specificity

Background: Clinically, subjects with posttraumatic stress disorder (PTSD) are viewed as hyperresponsive to a variety of stimuli. Psychophysiologic studies, however, have demonstrated hyperresponsiveness only to stimuli that are closely related to the original trauma. Methods: This set of experiments uses a variety of stimuli that vary in trauma- relatedness, arousal level, sensory modality stimulated, and degree of cognitive processing demanded to assess the extent of generalization of physiologic responses. Heart rate (HR), frontal electromyogram (EMG), and skin conductance (EDG) responses were measured during presentation of each stimulus. Results: PTSD subjects (n=15) had an elevated baseline EDG and increased HR and EMG responses to the trauma-related stimulus (combat sounds) compared to normal control subjects (n=11) and combat control subjects (n=10). No significant differences were noted between PTSD and control groups in response to nontrauma-related arousing stimuli. Conclusions: These results suggest that the physiologic hyperresponsivity of PTSD subjects is limited to stimuli closely associated with the inciting trauma.