The First Application of Trauma Event Centrality to Neurobiological Research: Assessing Cortisol Reactivity and...

Despite evidence suggesting links between trauma exposure and dysregulated hypothalamic-pituitary-adrenal (HPA) axis function-often manifesting as altered cortisol reactivity to stress-empirical findings remain inconsistent. These discrepancies may partially stem from reliance on dichotomous trauma classifications (i.e., presence/absence of potentially traumatic events [PTEs]) that fail to capture the subjective and contextual complexity of psychological traumatization. This study examined whether incorporating subjective trauma perceptions-specifically event centrality-and trauma type (interpersonal/non-interpersonal) would clarify associations between PTE exposure and blunted cortisol reactivity. Adults (N= 65; 42 female) participated in the Trier Social Stress Test, provided salivary cortisol samples, and completed trauma surveys. Multiple regression analyses revealed that higher event centrality was unexpectedly associated with greater cortisol reactivity in the full sample-an effect driven by female participants (b=7.46,p=.007,f²=.236). Subsequent analyses clarified that this relation was moderated by trauma type: women reporting highly central interpersonal trauma demonstrated bluntedcortisol reactivity (b=-19.10,p=.012,f²=.207), indicating an interaction between trauma type and subjective event centrality. Findings support the salience of dimensional trauma variables and sex-specific analyses in neurobiological research. The observed associations also present insights for identification of those at risk for dysregulated HPA axis function and targeted intervention design. By integrating both objective and subjective trauma indicators, this study provides nuance to our understanding of the impact of trauma on physiological stress systems-and contributes to a body of evidence suggesting that the subjective meaning of trauma may be a critical consideration in predicting health outcomes.