Interpersonal trauma exposure and startle reactivity to uncertain threat in individuals with alcohol use disorder

Background: Exposure to interpersonal trauma is highly prevalent within individuals with alcohol use disorder (AUD); however, the mechanisms underlying the pathway between trauma exposure and AUD are unclear. Preliminary evidence suggests that heightened reactivity to threats that are uncertain (U-threat) may characterize individuals with AUD and interpersonal trauma exposure and contribute to alcohol abuse within this subgroup of individuals; however, this hypothesis has yet to be tested. Method: The aim of the study was to examine whether heightened reactivity to U-threat characterizes individuals with AUD and a history of interpersonal trauma. Specifically, the study compared defensive reactivity to U-threat (and predictable threat [P-threat]) in those with: 1) AUD and a history of interpersonal trauma (AUD + Trauma); 2) AUD and no history of interpersonal trauma (AUD-Trauma); and 3) matched controls. Participants (N = 77) completed a well-validated threat-of-shock task and startle eyeblink potentiation was collected as an index of aversive responding. Results: Results revealed a group by threat condition interaction (F[4, 142] = 3.17, p = 0 . 03 ; eta G(2) = 0.08) such that individuals with AUD + Trauma exhibited greater startle reactivity to U-threat, but not P-threat, compared with individuals with AUD-Trauma and controls (who did not differ from each other). The findings were significant even when controlling for current anxiety and depression symptoms. Conclusions: Within individuals with AUD, those with a history of interpersonal trauma exposure may be a neurobiologically unique subtype characterized by exaggerated U-threat reactivity and high levels of anticipatory anxiety. Reactivity to U-threat may be a promising alcohol use prevention and intervention target for trauma-exposed individuals.