Big five traits and interpersonal goals during stressors as predictors of hair cortisol

Hair cortisol concentrations (HCC) provide a biomarker for stress adaptation, which has downstream health consequences. Personality traits (e.g., neuroticism) and social processes (e.g., chronic interpersonal goals) may confer risk or buffer against dysregulated cortisol secretion. However, few studies have examined personality or interpersonal factors predicting hair cortisol, which estimates longer-term secretion and therefore provides a potential biomarker for studying trait-like psychological processes. The present study investigated effects of personality traits and daily interpersonal goals during stressors on HCC. Participants (N = 90) reported Big Five traits at baseline, recorded interpersonal (self-image and compassionate) goals pursued during their worst psychosocial stressors for 4–5 weeks (1,949 entries), then provided a hair sample to estimate cortisol secretion over the past two months. As hypothesized, neuroticism predicted higher HCC, beyond other Big Five traits (b = 7.45, SE = 3.36, p = .029). Moreover, this effect was greater for those chronically striving to promote/protect one’s self-image during psychosocial stressors (b = 14.53, SE = 4.72, p = .003), and for those low in conscientiousness (b = 14.84, SE = 4.83, p = .003). Moderate extraversion was associated with higher HCC. Striving to support others (compassionate goals) exerted no direct or interactive effect on HCC, contrary to hypotheses. Results support the relevance of neuroticism and maladaptive interpersonal strivings to longer-term neuroendocrine responses, suggesting hair cortisol as a potential method for studying links of trait-like psychological and HPA processes. •Trait neuroticism uniquely predicted higher hair cortisol concentration.•Interpersonal goals during chronic social stressors amplified effects of neuroticism.•Trait conscientiousness blunted the effect of neuroticism on hair cortisol.