The differential impact of interpersonal and health related chronic stress on HPA axis functioning
AbstractChronic stress has been found to have detrimental physical and psychological effects (McEwen, 1998). However, the impact of chronic stress on HPA functioning remains unclear, varying between increased and decreased cortisol secretion (Heim et al., 2000). This may be due to the effect of distinct types of chronic stress (Miller et al., 2007). The current study examined how interpersonal and health related chronic stress differentially impact diurnal cortisol secretion, the cortisol awakening response (CAR), and cortisol reactivity to the Trier Social Stress Test (TSST). Participants included 60 undergraduates aged 17-58 years (68.3% female). The UCLA Life Stress Interview (LSI) was administered, assessing chronic stress over 12 months in 8 domains. Salivary cortisol was collected on two days at four time points including the CAR, and five time points across the TSST. Cortisol secretion was assessed using Area Under the Curve analyses relative to the ground (AUCG) and intercept (AUCI). Interpersonal chronic stress (Close Friend, Social, Romantic, Family) accounted for 18.1% of the variance in CAR AUCg (p= 0.04) and 17.9% of the variance in TSST AUCg (p = .05). Health related chronic stress accounted for 7.9% of the variance in TSST AUCg (p = .04), and 8.4% in AUCi (p = .04). Increased health related chronic stress predicted a decrease, whereas interpersonal chronic stress predicted an increase in cortisol secretion. These distinct patterns may account for disparities in previous research findings, and may help us clarify whether distinct clinical and health outcomes are related to distinct types of chronic stress.