Trait positive and negative emotionality differentially associate with diurnal cortisol activity

Area of Science:

• Psychoneuroendocrinology
• Personality Psychology
• Stress Physiology

Background:

• Inter-individual variability in hypothalamic-pituitary-adrenocortical (HPA) activity metrics, including diurnal cortisol decline, cortisol awakening response (CAR), and total cortisol output, has inconsistently related to personality traits like extraversion, positive affect (E/PA), neuroticism, and negative affect (N/NA).
• Previous inconsistencies may stem from varied cortisol sampling methods and reliance on self-reported traits, which are prone to bias and introspection limitations.

Purpose of the Study:

• To investigate dispositional correlates of HPA activity in healthy, midlife adults.
• To examine the association between multi-informant trait ratings of E/PA and N/NA with objective HPA activity measures.

Main Methods:

• Recruited 490 healthy, employed midlife volunteers (mean age=43 years; 54% Female; 86% White).
• Collected trait ratings from participants and two informants using the Positive and Negative Affect Schedule (PANAS) and NEO personality inventories (Extraversion, Neuroticism).
• Assessed cortisol levels across 3 workdays: awakening, +4h, +9h, and bedtime for diurnal slope and total output (AUC); awakening and 30 min post-awakening for CAR.
• Employed structural equation modeling to derive latent E/PA and N/NA factors and three latent cortisol factors (slope, CAR, AUC).

Main Results:

• After controlling for covariates (age, sex, race), higher latent E/PA was significantly associated with a steeper diurnal cortisol slope (Standardized β=-0.19, p=0.02) and a smaller CAR (Standardized β=-0.26, p=0.004).
• Latent N/NA showed no significant association with any cortisol metric (Standardized β's=-0.12 to 0.13, p's=0.10 to 0.53).
• The structural equation model demonstrated good fit to the data, indicating robust estimation of latent factors.

Conclusions:

• Positive emotionality (E/PA) is more closely linked to diurnal cortisol release patterns than negative emotionality (N/NA).
• Findings suggest that specific aspects of positive emotionality may influence the regulation of the HPA axis, particularly diurnal cortisol secretion.