Temporal Stability and Effect Dynamics between Executive Functions, Perceived Chronic Stress, and Hair Cortisol Concentrations

Accidents caused by human errors illustrate the fragility of cognitive processing and its coordination by executive functions against stress. To better understand how core executive functions change over time, influence each other, and are affected by chronic stress exposure, a prospective cohort study was conducted from 2016 to 2019. Five hundred sixteen German adults aged 25-55 years (mean age/education age: 38.0/11.3 years, 67% females, 94% occupied, 20% smokers) completed at least one internet-based biannual assessment of response inhibition, updating, and set shifting using a Go/NoGo, spatial 2-Back, and Number-Letter task, respectively. Chronic stress exposure was indicated by self-reports on the Perceived Stress Scale (PSS) and hair cortisol concentrations (HCC). Statistical analyses were performed by multivariatestochastic differential equation modeling. All indicators of executive functions (task-specific RTs in target trials or their contrast to nontarget trials) and chronic stress showed intraindividual stability over time (12% to 63% of their variance was attributable to trait influences). With respect to lagged mutual associations, faster Go/NoGo target RTs predicted faster Number-Letter target RTs later in time, while faster Number-Letter target RTs predicted higher HCC later in time (both with maximum effect sizes of d [approximately equal to] 0.1 standard deviations). However, PSS was not predictive of later HCC and vice versa. None of the chronic stress indicators significantly predicted indicators of executive functions at subsequent time points. These findings suggest that set shifting is capable of modulating the body's physiological response to chronic stress exposure, whereas executive functions appear comparably robust against chronic stress exposure.