Pupillary Response to Affective Voices: Physiological Responsivity and Posttraumatic Stress Disorder

Posttraumatic stress disorder (PTSD) is related to dysfunctional emotional processing, thus motivating the search for physiological indices that can elucidate this process. Toward this aim, we compared pupillary response patterns in response to angry and fearful auditory stimuli among 99 adults, some with PTSD (n = 14), some trauma-exposed without PTSD (TE; n = 53), and some with no history of trauma exposure (CON; n = 32). We hypothesized that individuals with PTSD would show more pupillary response to angry and fearful auditory stimuli compared to those in the TE and CON groups. Among participants who had experienced a traumatic event, we explored the association between PTSD symptoms and pupillary response; contrary to our prediction, individuals with PTSD displayed the least pupillary response to fearful auditory stimuli compared those in the TE, B = -0.022, p = .077, and CON, B = -0.042, p = .002, groups, but they did not differ on angry auditory stimuli, B = 0.019, p = .118 and B = 0.006, p = .634, respectively. It is important to note that within-group analyses revealed that participants with PTSD differed significantly in their response to angry versus fearful stimuli, B = -0.032, p = .015. We also found a positive association between PTSD symptoms and pupillary response to angry stimuli. Our findings suggest that differential pupil response to anger and fear stimuli may be a promising way to understand emotional processing in PTSD.