Early trauma exposure moderates associations between cortisol reactivity and youth anxiety and externalizing symptoms.

Early (before age 6) potentially traumatic events (PTEs) may interact with hypothalamic-pituitary-adrenal (HPA) axis functioning to shape outcomes involving externalizing problems and anxiety. However, directions of effects remain unclear. This study examined associations between aspects of HPA axis reactivity, anxiety, and externalizing problems over two years by early PTE exposure history, while statistically capturing the co-occurrence of symptom domains. Youth (N = 189; Mage = 10.96 years, SD = 2.51, Range = 8-15; 52.4% female, 47.1% male; 50.3% White, 35.4% Black/African American, 6.4% Other; 7.4% Hispanic/Latine) were included if they had early PTE exposure (n = 107) or had never experienced a PTE (n = 82). HPA axis reactivity to social stress was calculated using area under the curve with respect to ground (AUCg) and increase (AUCi). For youth with early PTE exposure, higher AUCg was concurrently associated with more externalizing symptoms and greater predominance of externalizing over anxiety. Blunted AUCi predicted increasing predominance of externalizing for the early PTE group, but elevated AUCi predicted increases in anxiety for the no PTE group. Findings highlight distinct roles of overall and reactive HPA axis functioning in shaping outcomes following early trauma.