General Trust Buffers the Effects of Stressful Life Events on College Students' Diurnal Cortisol Profiles

• In Event: Adverse experiences and adolescents’ physiological and mental health: The protective effects of resources

Abstract

Objectives: Cumulative life stress is one of the most well-established psychosocial determinants of health. There is a growing interest in examining what can protect the health of individuals living in high-stress circumstances. We proposed that individual's general trust, a valuable social resource, would protect high-stress college students from stress-related physiological alterations, as measured through altered pattern of diurnal cortisol secretion. The current study aimed at: (1) testing the main effects of stressful life events and general trust on HPA axis activity, indexed by five parameters of daily cortisol secretion (i.e., wakeup cortisol, CAR, cortisol slope, bedtime cortisol, and total cortisol secretion across the day), which were widely used in the previous psychoneuroendocrinology research; and (2) examining the buffering effect of general trust on the associations between stressful life events and diurnal cortisol profiles.

Methods: A sample of 108 college students (aged 17-20) completed a battery of psychological scales, including stressful life events and general trust. Diurnal cortisol assessments included collection of saliva samples three times a day for 3 days, from which five cortisol parameters (cortisol at awakening, cortisol awakening response, cortisol slope, bedtime cortisol, and total cortisol secretion) were derived. The intra-assay and inter-assay coefficients of variations in this study were 8.6% and 12.3%, respectively. Hierarchical linear modeling and multiple linear regression were used to examine the research questions.

Results: Main effect models revealed that more life events were associated with more blunted cortisol slope and higher bedtime cortisol levels. Moderating effect models showed that the interaction between stressful life events and general trust significantly predicted cortisol slope and bedtime cortisol levels. As shown in Figure 1 and Figure 2a, at low levels of general trust, participants with more life events exhibited more blunted (less healthy) cortisol slope and higher levels of bedtime cortisol than their low-stress counterparts. However, at high levels of general trust, the effects of stressful life events on cortisol slope and bedtime cortisol were not significant. We further probed the marginal-effects (or regions-of-significance) for this interaction and found that the estimated simple slopes for the association between stressful life events and bedtime cortisol were significant and positive when standardized general trust (z score) was 0.45 or lower (Figure 2b).

Conclusions: Our results suggest that general trust might serve as a protective psychological mechanism and buffer the detrimental effects of life events on diurnal cortisol secretion. Understanding the biological mechanisms by which general trust links to health paves the way for making efforts to prevent allostatic load, and ultimately, reduce risk of health problems in individuals facing high levels of cumulative stress.

Authors

• Lihua Chen
  Presenting Author

• Hongfei Du, Beijing Normal University

• Peilian Chi, University of Macau