Blunted endocrine response to a combined physical-cognitive stressor in adults with early life adversity.

The negative health effects of early life adversity (ELA) continue long into adulthood. Changes in the physiological response to psychosocial stressors have been proposed to mediate this effect. However, many previous studies have come to contradicting conclusions as to whether ELA induces a long-term increase or decrease in stress reactivity. Therefore, we tested the association of ELA exposure and adult stress reactivity in a sample of early life adoptees and controls. Two previously validated stressful elements (bilateral feet CPT and the Paced Auditory Serial Addition Task (PASAT)) were combined in an extended Cold Pressor Test (CPT). This test was performed on 22 participants who had experienced severe ELA (separation from biological parents, institutionalization, and adoption in early childhood), and in 22 age-matched control participants. A prior history of ELA was associated with blunted reactivity of the hypothalamic-pituitary-adrenal (HPA) axis (Cohen´s d = 0.680). Cardiovascular reactivity remained unchanged, and affective reactivity (self-report ratings) were increased in participants exposed to ELA compared to the control group (range Cohen´s d: 0.642-0.879). Our results suggest that the activity of the HPA axis reactivity was inhibited in ELA participants. Importantly, cardiovascular stress responsiveness was not affected by ELA. This separation of the HPA axis and cardiovascular stress responses may best be explained by ELA selectively enhancing central feedback-sensitivity to glucocorticoids, but preserving cardiovascular/ autonomic stress reactivity.