Impact of Trauma Type on Startle Reactivity to Predictable and Unpredictable Threats.

ABSTRACT: Trauma exposure has been repeatedly linked to psychophysiological threat reactivity, although the directionality of this association has been inconsistent. Several factors likely contribute to inconsistent findings including type of trauma and threat paradigm. The present study therefore examined the impact of trauma type on psychophysiological reactivity to predictable (P-) and unpredictable (U-) threat in young adults (N = 112). Participants were classified into three groups: history of interpersonal or noninterpersonal trauma, or no history of trauma. Startle eyeblink potentiation was recorded during a well-validated threat-of-shock paradigm. Results indicated individuals with interpersonal trauma exposure displayed exaggerated startle reactivity to U-threat (only) compared with both other groups. In contrast, individuals with noninterpersonal trauma exhibited blunted startle reactivity to U-threat (only) compared with both other groups. Findings reveal that trauma and threat type influence threat reactivity and that those with a history of interpersonal trauma may uniquely display exaggerated sensitivity to stressors that are uncertain.