The cortisol awakening response and the big five personality dimensions

Dark Triad Personality Traits, Second-to-Forth Digit Ratio (2D:4D) and Circulating Testosterone and Cortisol Levels

INTRODUCTION

Dark Triad (DT) personality traits (psychopathy, Machiavellianism, and narcissism) show sex differences and associations with hormones. Understanding aetiology may assist in mitigating the harm of these potentially adverse characteristics. Low second-to-fourth digit ratio (2D:4D) is hypothesised to be a marker of high prenatal testosterone exposure and may provide important information about organisational hormones. The aim of the present study was to measure Dark Triad and Big 5 personality traits in relation to digit ratio, salivary testosterone, and cortisol.

METHODS

A non-clinical sample (N=268; 49.25% Female, age M25.20 ± 8.77yrs) completed the Short Dark Triad and International Personality Inventory Pool - Mini. Afternoon saliva was analysed for testosterone and cortisol, and 2D:4D finger ratios were measured.

RESULTS

Males scored higher on DT traits than females. Females scored higher on Big 5 agreeableness and neuroticism. Males had higher testosterone and cortisol levels and lower 2D:4D than females. Digit ratio correlated inversely with salivary testosterone, Machiavellianism, and psychopathy. Testosterone levels correlated positively with cortisol levels and psychopathy and negatively with agreeableness, neuroticism, and Machiavellianism.

CONCLUSIONS

These results provide indications that Machiavellianism and psychopathy (Dark Triad) traits, but not narcissism or Big 5 traits, are linked to markers of prenatal testosterone exposure. Results also replicate sex differences seen in 2D:4D digit ratios, with males having a shorter second-relative-to-forth finger. Links between circulating testosterone, digit ratios, cortisol and personality traits provide further information about potential biological bases of personality.

The relationship between sex, personality traits, and the hypothalamic-pituitary-adrenocortical axis

The aim of our study was to examine whether there are sex-based differences in the relationship between personality traits and hypothalamic-pituitary-adrenal (HPA) axis measures. A total of 106 healthy volunteers (56.6% women; age: 48.0 ± 15.8 years) were studied. The revised temperament and character inventory (TCI-R) and the Childhood Trauma Questionnaire (CTQ) were administered. HPA axis function was assessed using three dynamic measures: the cortisol awakening response (CAR), the diurnal cortisol slope, and the cortisol suppression ratio with 0.25 mg of dexamethasone (DSTR). Female sex was associated with an increased CAR and a more flattened diurnal cortisol slope, although a negative significant interaction between harm avoidance and female sex was found. Regarding the DSTR, perseverance was associated with increased cortisol suppression after dexamethasone; sex did not affect this association. Our study suggests that the relationship between specific personality traits (harm avoidance) and HPA axis measures (CAR, diurnal slope) differs according to sex.

The cortisol awakening response and the late positive potentials evoked by unpleasant emotional pictures in healthy adults

The cortisol awakening response (CAR) refers to a sharp rise in cortisol concentrations within the 45 min following morning awakening. Alterations in CAR have been associated with various internalizing symptoms and brain function. The current study aimed to investigate the association between CAR and neural activity in response to unpleasant emotional pictures. A total of 46 healthy adults (22.55 years ± 1.69) collected saliva samples at 0, 30, and 45 min post-awakening on two days to assess the CAR. In the afternoon after CAR measurement on the first day, electroencephalograms were recorded when the participants completed a passive viewing task. The results showed that a greater CAR was associated with a decreased late positive potential difference score between unpleasant and neutral stimuli. This finding indicates that a larger CAR may be associated with decreased attentional engagement to unpleasant emotional information in healthy adults.

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

Background

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.

Method

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.

Results

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.

Conclusions

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.

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Trait neuroticism uniquely predicted higher hair cortisol concentration.

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Interpersonal goals during chronic social stressors amplified effects of neuroticism.

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Trait conscientiousness blunted the effect of neuroticism on hair cortisol.

Does salivary cortisol secretion mediate the association of work-related stressors with workers' depression?

PURPOSE

The purpose of this study was to verify the mediating role salivary cortisol intensity plays between work organization conditions and depression. This study simultaneously considered psychological and physiological (salivary cortisol) stress indicators on workers' depression in a single model.

METHODS

We relied on cluster sampling of 341 workers in 34 Quebec establishments. Five saliva samples (on awakening, 30 min after awakening, at 2:00 p.m., 4:00 p.m., and bedtime) were collected per day. The weekly collection period spanned a period of 3 days (1 day off and 2 work days). We evaluated the main effects of work organization conditions on salivary cortisol intensity and depression, as well as the mediation effect of salivary cortisol intensity between work organization conditions and depression. To adjust for design effects, the direct and indirect (mediation) associations between the variables were evaluated while accounting for the non-independence of the data.

RESULTS

Skill utilization and job insecurity were associated with salivary cortisol intensity, while psychological demands and job insecurity were associated with higher depression levels. Work-related variables were not found to have an indirect effect on depression via worker's salivary cortisol (AUC) intensity.

CONCLUSION

Work-related stressors examined in this study did not indirectly affect worker's depression levels. Additional studies are necessary to be able to identify all work-related stressors that could potentially increase worker's depression levels through salivary cortisol.

Associations between Personality Traits and Basal Cortisol Responses in Sailing Athletes

There is a paucity of literature regarding the psycho-physiological profiles of sailors on board. This study aimed at providing empirical evidence on the individual differences between bowmen and helmsmen taking into account a biopsychological perspective. To this purpose, sailors' profiles were examined by focusing on the association between personality traits and basal cortisol. The sample was composed of 104 athletes (M_age = 21.32, SD = 0.098; F = 35%), who fulfilled a self-reported questionnaire including a socio-demographic section and the Big Five questionnaire. Cortisol samples were collected on the day before the competition, within 30 min after awakening. T-test analysis showed significant differences on cortisol levels: bowmen obtained higher levels on cortisol responses compared to helmsmen. No differences emerged on personality traits between athletes' roles. Bivariate associations showed positive associations of cortisol responses with extraversion and conscientiousness in bowmen, whereas no significant associations of cortisol with personality traits were found in helmsmen. Regression analyses confirmed that sex and extraversion predicted higher level of cortisol responses. Results were discussed in terms of a bio-psychosocial theoretical approach and provided findings on the relationships between personality trait and the hypothalamus-pituitary adrenal (HPA) system in dinghy sailors. Suggestions for a more suitable selection of sailor roles were given to coaches in order to improve athletes' performance.

Challenging the binary: Gender/sex and the bio-logics of normalcy

BACKGROUND

We are witnessing renewed debates regarding definitions and boundaries of human gender/sex, where lines of genetics, gonadal hormones, and secondary sex characteristics are drawn to defend strict binary categorizations, with attendant implications for the acceptability and limits of gender identity and diversity.

AIMS

Many argue for the need to recognize the entanglement of gender/sex in humans and the myriad ways that gender experience becomes biology; translating this theory into practice in human biology research is essential. Biological anthropology is well poised to contribute to these societal conversations and debates. To do this effectively, a reconsideration of our own conceptions of gender/sex, gender identity, and sexuality is necessary.

METHODS

In this article, we discuss biological variation associated with gender/sex and propose ways forward to ensure we are engaging with gender/sex diversity. We base our analysis in the concept of "biological normalcy," which allows consideration of the relationships between statistical distributions and normative views. We address the problematic reliance on binary categories, the utilization of group means to represent typical biologies, and document ways in which binary norms reinforce stigma and inequality regarding gender/sex, gender identity, and sexuality.

DISCUSSION AND CONCLUSIONS

We conclude with guidelines and methodological suggestions for how to engage gender/sex and gender identity in research. Our goal is to contribute a framework that all human biologists can use, not just those who work with gender or sexually diverse populations. We hope that in bringing this perspective to bear in human biology, that novel ideas and applications will emerge from within our own discipline.

Abnormal cortisol awakening responses in patients with neurotic and personality disorders admitted for psychotherapy in day hospital

Dysregulation of the hypothalamic-pituitary-adrenal axis (HPA axis) has been associated with various psychiatric conditions. The most interesting parameter of the HPA axis function is cortisol awakening response (CAR). Few data exist about the CAR in anxiety or personality disorders and findings are often contradictory showing blunted or increased CAR compared with control groups. The goal of this study was to determine whether patients with neurotic and personality disorders show a specific CAR pattern. The study population comprised 130 patients, mainly females (71.5%), with the primary diagnosis of a neurotic disorder or personality disorder according to ICD-10 admitted for psychotherapy in a day hospital. Pre-treatment cortisol levels were measured in three saliva samples collected in one day. The Symptom Checklist "O" and MMPI-2 were used to assess the pre-treatment levels of patients' symptoms and personality traits. The study revealed a high percentage of CAR non-responders (cortisol increase of less than 2.5 nmol/l) in the study group (43.1%), particularly in females. 49% of them were CAR non-responders compared with 28% in males and 25% in the general population, respectively. CAR non-responders did not differ from the remainder in clinical characteristics. Four different CAR patterns were found in the study group: negative (26.9%), blunted (26.1%), normal (25.4%) and elevated (21.6%) as well as a particular type was not related to clinical characteristics of the patients. The study suggests that abnormal CAR types are observed in patients with neurotic and personality disorders and further research into the mechanism of the findings is required.

The Psycho-Physiological Profile of Adolescent Elite Sailors: Testing a Three-Way Moderation Model

The present study aimed at extending the work on individual differences, in the relationship between personality traits and the cortisol response, by examining the interaction effects of sex and the role category of Italian adolescent elite dinghy sailors. Seventy athletes completed a self-reported questionnaire including socio-demographic data, information about the role played on board (helmsmen or bowmen) and the Big Five Questionnaire-2. Salivary cortisol samples were collected at 30 min after awakening the day before competitions. Main findings from bivariate correlations showed positive associations among cortisol levels, extraversion and consciousness in both male and female bowmen groups. The moderation and moderated moderation analyses further indicated (1) a three-way interaction effect in the relationship between extraversion and salivary cortisol, (2) a marginal significant three-way interaction effect in the relationship between neuroticism and salivary cortisol, and (3) no other personality dimensions were significantly predictive of the outcome variable. Our results provided evidence not only about sex differences, but also about the role played on board by the sailors in the linkages between personality traits and the biomarker of the trait component of HPA axis functioning.

Personality and Hypothalamic-Pituitary-Adrenal Axis in Older Men and Women

Personality has been related to health and mortality risk, which has created interest in the biological pathways that could explain this relationship. Although a dysregulation of the hypothalamic–pituitary–adrenal (HPA) axis has been associated with health outcomes and aging, few studies have explored the association between personality and HPA axis functioning in older adults. In addition, it has been suggested that sex could moderate the relationship between personality and HPA axis functioning. Thus, our aim was to analyze the relationship between the big five personality traits and the diurnal cortisol pattern in older adults, as well as sex differences in this relationship. To do so, 79 older people (40 men and 39 women) from 59 to 81 years old (M = 69.19, SD = 4.60) completed the NEO-Five-Factor Inventory (FFI) to measure neuroticism, conscientiousness, extraversion, openness, and agreeableness. Saliva samples were provided on three consecutive days (awakening; 15, 30, and 45 min post-awakening; and bedtime) in order to analyze the diurnal cortisol pattern and, specifically, two cortisol indexes: the cortisol awakening response (CAR) and the diurnal cortisol slope (DCS). Results showed that neuroticism and conscientiousness moderated the diurnal cortisol pattern. Thus, individuals with higher neuroticism and lower conscientiousness scores showed higher bedtime cortisol levels, suggesting a less healthy diurnal cortisol pattern. Regarding the cortisol indexes, higher neuroticism and lower conscientiousness were related to greater CAR and DCS. Sex moderated the association between extraversion and the DCS. Specifically, higher extraversion was related to a lower DCS only in women. Openness and agreeableness were not related to the diurnal cortisol pattern. In conclusion, our results show that in older adults, neuroticism is a vulnerability factor for HPA axis dysregulation, with possible adverse effects on health. By contrast, conscientiousness, and extraversion only in women, appear to be protective factors of HPA axis functioning, with potential beneficial effects on health.

Predicting change trajectories of neuroticism from baseline brain structure using whole brain analyses and latent growth curve models in adolescents

Adolescence is a vulnerable time for personality development. Especially neuroticism with its link to the development of psychopathology is of interest concerning influential factors. The present study exploratorily investigates neuroanatomical signatures for developmental trajectories of neuroticism based on a voxel-wise whole-brain structural equation modelling framework. In 1,814 healthy adolescents of the IMAGEN sample, the NEO-FFI was acquired at three measurement occasions across five years. Based on a partial measurement invariance second-order latent growth curve model we conducted whole-brain analyses on structural MRI data at age 14 years, predicting change in neuroticism over time. We observed that a reduced volume in the pituitary gland was associated with the slope of neuroticism over time. However, no relations with prefrontal areas emerged. Both findings are discussed against the background of possible genetic and social influences that may account for this result.

Interdependent self-construal modulates the adrenocortical stress response in the socially evaluated cold-pressor test

Previous studies suggested that the Trier social stress test (TSST) induced a higher cortisol stress response in individuals with high interdependent self-construal (InterSC) as compared to those with low InterSC, and that participants' perception of social evaluative threat mediated the association between InterSC and cortisol stress response. To further examine if individuals with high InterSC exhibit a strong psychological stress response independent of the stress paradigm, the current study investigated the stress response of individuals with high InterSC in a socially evaluated cold-pressor test (SECPT) paradigm, which has also been shown to reliably increase hypothalamus-pituitary-adrenal (HPA) activity with a social evaluative element. Fifty-five healthy participants (29 females; mean age  =  20.55 years) completed the Self-Construal Scale and their salivary cortisol samples were collected at 0, 30, 45, and 60 minutes after waking up on a weekday morning. Participants' cardiovascular and adrenocortical stress responses in the SECPT were also measured while they immersed their hand in ice water, and they were observed by the experimenter and videotaped during this task. Our results indicated that participants with high InterSC showed a higher level of cortisol awakening response (CAR). Additionally, they perceived higher levels of social evaluative threat and exhibited higher saliva cortisol response to the SECPT. Taken together, the present findings and those obtained from previous studies suggest a significant and reliable role of InterSC in regulating biological and psychological stress responses.

Correlation between gut microbiota and personality in adults: A cross-sectional study

Personality affects fundamental behavior patterns and has been related with health outcomes and mental disorders. Recent evidence has emerged supporting a relationship between the microbiota and behavior, referred to as brain-gut relationships. Here, we first report correlations between personality traits and gut microbiota. This research was performed using the Revised NEO Personality Inventory and the sequencing data of the 16S rRNA gene in 672 adults. The diversity and the composition of the human gut microbiota exhibited significant difference when stratified by personality traits. We found that personality traits were significantly correlated with diversity of gut microbiota, while their differences were extremely subtle. High neuroticism and low conscientiousness groups were correlated with high abundance of Gammaproteobacteria and Proteobacteria, respectively when covariates, including age, sex, BMI and nutrient intake, were controlled. Additionally, high conscientiousness group also showed increased abundance of some universal butyrate-producing bacteria including Lachnospiraceae. This study was of observational and cross-sectional design and our findings must be further validated through metagenomic or metatranscriptomic methodologies, or metabolomics-based analyses. Our findings will contribute to elucidating potential links between the gut microbiota and personality, and provide useful insights toward developing and testing personality- and microbiota-based interventions for promoting health.

Psychosocial functioning and the cortisol awakening response: Meta-analysis, P-curve analysis, and evaluation of the evidential value in existing studies

Cortisol levels rise immediately after awakening and peak approximately 30-45min thereafter. Psychosocial functioning influences this cortisol awakening response (CAR), but there is considerable heterogeneity in the literature. The current study used p-curve and meta-analysis on 709 findings from 212 studies to test the evidential value and estimate effect sizes of four sets of findings: those associating worse psychosocial functioning with higher or lower cortisol increase relative to the waking period (CARi) and to the output of the waking period (AUCw). All four sets of findings demonstrated evidential value. Psychosocial predictors explained 1%-3.6% of variance in CARi and AUCw responses. Based on these effect sizes, cross-sectional studies assessing CAR would need a minimum sample size of 617-783 to detect true effects with 80% power. Depression was linked to higher AUCw and posttraumatic stress to lower AUCw, whereas inconclusive results were obtained for predictor-specific effects on CARi. Suggestions for future CAR research are discussed.

Neuroticism and cortisol: The importance of checking for sex differences

Existent research documents an unclear and contradictory pattern between cortisol and personality variables, especially neuroticism. Specifically, no effect, positive correlations and negative correlations have all been reported to exist between cortisol and neuroticism. The current study tested whether males and females have a fundamentally different relationship between HPA activation and neuroticism and if this might partially account for some of the discrepancy in findings. Saliva samples (n=183) for cortisol were collected three times across a 90min period. Neuroticism was measured via the NEO-FFI. For men, neuroticism was positively correlated with cortisol level (r=.29). For women it was negatively correlated. The negative correlation between neuroticism and cortisol level remained when oral contraceptive use was statistically controlled, and the statistical significance actually increased (partial r=-.20). This suggests a slight suppressor effect, explainable by prior research on correlates of oral contraceptive use. Overall, these findings may offer some explanation for the discrepant results that have been reported in the existing literature regarding neuroticism and cortisol measures.