Human models in acute and chronic stress: assessing determinants of individual hypothalamus-pituitary-adrenal axis activity and reactivity

Eight weeks of high-intensity interval training versus stretching do not change the psychoneuroendocrine response to a social stress test in emotionally impulsive humans

PURPOSE

Research supports physical activity as a method to heighten stress resistance and resilience through positive metabolic alterations mostly affecting the neuroendocrine system. High-intensity interval training (HIIT) has been proposed as a highly effective time-saving method to induce those changes. However, existing literature relies heavily on cross-sectional analyses, with few randomised controlled trials highlighting the necessity for more exercise interventions. Thus, this study aims to investigate the effects of HIIT versus an active control group on the stress response to an acute psychosocial stressor in emotionally impulsive humans (suggested as being strong stress responders).

METHODS

The study protocol was registered online (DRKS00016589) before data collection. Sedentary, emotionally impulsive adults (30.69 ± 8.20 y) were recruited for a supervised intervention of 8 weeks and randomly allocated to either a HIIT (n = 25) or a stretching group (n = 19, acting as active controls). Participants were submitted to a test battery, including saliva samples, questionnaires (self-efficacy- and perceived stress-related), visual analogue scales (physical exercise- and stress-related), and resting electroencephalography and electrocardiography assessing their reaction to an acute psychological stressor (Trier Social Stress Test) before and after the exercise intervention.

RESULTS

HIIT increased aerobic fitness in all participants, whereas stretching did not. Participants from the HIIT group reported perceiving exercising more intensively than those from the active control group (ƞp2 = 0.108, p = 0.038). No further group differences were detected. Both interventions largely increased levels of joy post-TSST (ƞp2 = 0.209, p = 0.003) whilst decreasing tension (ƞp2 = 0.262, p < 0.001) and worries (ƞp2 = 0.113, p = 0.037). Finally, both interventions largely increased perceived levels of general self-efficacy (ƞp2 = 0.120, p = 0.029).

CONCLUSION

This study suggests that 8 weeks of HIIT does not change the psychoneuroendocrine response to an acute psychological stress test compared to an active control group in emotionally impulsive humans. Further replications of supervised exercise studies highly powered with active and passive controls are warranted.

Bridging childhood to adulthood: the impact of early life stress on acute stress responses

Background

Childhood trauma exerts enduring impacts on the physical and psychological well-being of individuals in adulthood, influencing their daily functioning. This study aims to investigate the impact of childhood trauma on stress recovery in adults, concentrating on heart rate variations during acute stress exposure.

Methods

A cohort of 126 participants completed the Childhood Trauma Questionnaire (CTQ) and underwent the Trier Social Stress Test (TSST) to elicit acute stress, with continuous heart rate (HR) monitoring for stress recovery assessment.

Results

The results revealed a negative correlation between childhood trauma and stress recovery, prominently observed in instances of emotional neglect and abuse. Individuals with heightened childhood trauma exhibited protracted stress recovery following acute stress exposure.

Conclusion

Childhood traumatic experiences were associated with the recovery from acute stress, as indicated by heart rate indices. These findings contribute to the foundational framework for psychological interventions tailored to individuals with a history of childhood trauma.

Gene‒environment interaction effect of hypothalamic‒pituitary‒adrenal axis gene polymorphisms and job stress on the risk of sleep disturbances

Background

Studies have shown that chronic exposure to job stress may increase the risk of sleep disturbances and that hypothalamic‒pituitary‒adrenal (HPA) axis gene polymorphisms may play an important role in the psychopathologic mechanisms of sleep disturbances. However, the interactions among job stress, gene polymorphisms and sleep disturbances have not been examined from the perspective of the HPA axis. This study aimed to know whether job stress is a risk factor for sleep disturbances and to further explore the effect of the HPA axis gene × job stress interaction on sleep disturbances among railway workers.

Methods

In this cross-sectional study, 671 participants (363 males and 308 females) from the China Railway Fuzhou Branch were included. Sleep disturbances were evaluated with the Pittsburgh Sleep Quality Index (PSQI), and job stress was measured with the Effort-Reward Imbalance scale (ERI). Generalized multivariate dimensionality reduction (GMDR) models were used to assess gene‒environment interactions.

Results

We found a significant positive correlation between job stress and sleep disturbances (P < 0.01). The FKBP5 rs1360780-T and rs4713916-A alleles and the CRHR1 rs110402-G allele were associated with increased sleep disturbance risk, with adjusted ORs (95% CIs) of 1.75 [1.38-2.22], 1.68 [1.30-2.18] and 1.43 [1.09-1.87], respectively. However, the FKBP5 rs9470080-T allele was a protective factor against sleep disturbances, with an OR (95% CI) of 0.65 [0.51-0.83]. GMDR analysis indicated that under job stress, individuals with the FKBP5 rs1368780-CT, rs4713916-GG, and rs9470080-CT genotypes and the CRHR1 rs110402-AA genotype had the greatest risk of sleep disturbances.

Conclusions

Individuals carrying risk alleles who experience job stress may be at increased risk of sleep disturbances. These findings may provide new insights into stress-related sleep disturbances in occupational populations.

Cortisol Reactivity to Acute Psychosocial Stress in Physician Burnout

BACKGROUND

Physician burnout, characterized by chronic job-related stress leading to emotional exhaustion, depersonalization, and reduced personal accomplishment. This cross-sectional study investigates cortisol reactivity in male physicians with burnout compared to healthy controls during an acute psychosocial stress test.

METHODS

Sixty male physicians (30 burnout, 30 healthy controls) participated between September 2019 and December 2021 to investigate the impact of burnout on cardiovascular health. Salivary cortisol levels were measured before and after a Trier Social Stress Test (TSST). Burnout was assessed with the Maslach Burnout Inventory-Human Services Survey (MBI-HSS). Covariates included age, BMI, and physical activity. Data were analyzed using repeated measures analysis and area under the curve analysis.

RESULTS

Male physicians with burnout exhibited significantly greater cortisol reactivity during the TSST, notably post-stress to 15 min post-stress. Emotional exhaustion correlated with reduced cortisol increase from pre-stress and smaller post-stress to 15- and 45-min declines.

DISCUSSION

Findings suggest heightened cortisol reactivity in male physicians with burnout, possibly reflecting initial chronic stress stages. This study highlights the necessity for long-term research on cortisol's influence on cardiovascular health and stress responses across diverse groups.

CONCLUSIONS

The findings contribute to comprehending physiological responses in burnout-afflicted physicians, emphasizing cortisol reactivity's pivotal role in stress-related research and its potential health implications, particularly within the burnout context.

The impacts of latent profiles and transitions of stresses on adolescent mental health: A person-centred analysis

Research has demonstrated robust links between adolescent stress and serious psychological problems. The current study aimed to identify latent stress profiles of 1510 adolescents (59.7% females; Mage  = 16.77 years, SD = 0.86) based on five stresses (parental stresses, family environment stresses, academic stresses, teacher stresses, and peer stresses) at three time points (T1/2/3). Moreover, this study would investigate the transition patterns of these profiles over time and examine the associations between the profiles and adverse psychological symptoms (e.g., anxiety, depression, nonsuicidal self-injury [NSSI], and suicidal ideation). Three latent stress profiles were identified, including High-stress profile, Medium-stress profile, and Low-stress profile. The three profiles were significantly different on the levels of T1/2/3 anxiety, depression, NSSI, and suicidal ideation. The profile memberships remained relatively stable across three time points. Notably, the present study found gender differences, with boys were more likely to be in the High-stress profile and to transition from the Medium- to the High-stress profile, compared to girls. Furthermore, left-behind adolescents were more likely to be in the High-stress profile than non-left-behind adolescents. The findings highlight the importance of adopting 'this-approach-fits-this-profile' interventions for adolescents. Parents and teachers are advised to adopt different strategies for girls and boys.

Sleep, brain systems, and persistent stress in early adolescents during COVID-19: Insights from the ABCD study

PURPOSE

The first year of the COVID-19 pandemic constituted a major life stress event for many adolescents, associated with disrupted school, behaviors, social networks, and health concerns. However, pandemic-related stress was not equivalent for everyone and could have been influenced by pre-pandemic factors including brain structure and sleep, which both undergo substantial development during adolescence. Here, we analyzed clusters of perceived stress levels across the pandemic and determined developmentally relevant pre-pandemic risk factors in brain structure and sleep of persistently high stress during the first year of the COVID-19 pandemic.

METHODS

We investigated longitudinal changes in perceived stress at six timepoints across the first year of the pandemic (May 2020-March 2021) in 5559 adolescents (50 % female; age range: 11-14 years) in the United States (U.S.) participating in the Adolescent Brain Cognitive Development (ABCD) study. In 3141 of these adolescents, we fitted machine learning models to identify the most important pre-pandemic predictors from structural MRI brain measures and self-reported sleep data that were associated with persistently high stress across the first year of the pandemic.

RESULTS

Patterns of perceived stress levels varied across the pandemic, with 5 % reporting persistently high stress. Our classifiers accurately detected persistently high stress (AUC > 0.7). Pre-pandemic brain structure, specifically cortical volume in temporal regions, and cortical thickness in multiple parietal and occipital regions, predicted persistent stress. Pre-pandemic sleep difficulties and short sleep duration were also strong predictors of persistent stress, along with more advanced pubertal stage.

CONCLUSIONS

Adolescents showed variable stress responses during the first year of the COVID-19 pandemic, and some reported persistently high stress across the whole first year. Vulnerability to persistent stress was evident in several brain structural and self-reported sleep measures, collected before the pandemic, suggesting the relevance of other pre-existing individual factors beyond pandemic-related factors, for persistently high stress responses.

Antinociceptive effect of intermittent fasting via the orexin pathway on formalin-induced acute pain in mice

It has been suggested that stress responses induced by fasting have analgesic effects on nociception by elevating the levels of stress-related hormones, while there is limited understanding of pain control mechanisms. Here, we investigated whether acute or intermittent fasting alleviates formalin-induced pain in mice and whether spinal orexin A (OXA) plays a role in this process. 6, 12, or 24 h acute fasting (AF) and 12 or 24 h intermittent fasting (IF) decreased the second phase of pain after intraplantar formalin administration. There was no difference in walking time in the rota-rod test and distance traveld in the open field test in all groups. Plasma corticosterone level and immobility time in the forced swim test were increased after 12 h AF, but not after 12 h IF. 12 h AF and IF increased not only the activation of OXA neurons in the lateral hypothalamus but also the expression of OXA in the lateral hypothalamus and spinal cord. Blockade of spinal orexin 1 receptor with SB334867 restored formalin-induced pain and spinal c-Fos immunoreactivity that were decreased after 12 h IF. These results suggest that 12 h IF produces antinociceptive effects on formalin-induced pain not by corticosterone elevation but by OXA-mediated pathway.

Hypothalamic-pituitary-adrenal axis responsivity during adolescence in relation to psychopathic personality traits later in life

Psychopathic personality traits have been linked to low physiological arousal, particularly among high risk and forensic samples. A core indicator of physiological arousal is the activity of the hypothalamic-pituitary-adrenal (HPA) axis; however, findings of a link between HPA axis functioning and psychopathic personality traits have been inconsistent. Furthermore, given sex differences in both HPA axis responsivity and psychopathic personality traits, the association may be expected to differ between men and women. The aim of this study was to investigate the association between HPA axis responsivity in mid-adolescence and psychopathic personality traits in early adulthood and determine whether the association was moderated by sex. We examined this link in a general population sample of twins (N = 556). Adolescents participated in a psychosocial stress task during which samples of salivary cortisol were collected (11-15 years) and reported psychopathic personality traits using the Triarchic Psychopathy Measure (19-20 years). Multilevel linear regression models were estimated in which psychopathic personality traits (boldness, meanness and disinhibition), and their interactions with sex, were regressed on HPA axis responsivity. The study was pre-registered on the Open Science Framework (osf.io/gs2a8). Preliminary analyses showed that cortisol levels did not increase significantly during the stressor task but decreased during recovery. Results showed that there was no association between HPA axis responsivity in mid-adolescence and psychopathic personality traits in early adulthood. The associations were not moderated by sex. Findings suggest that HPA axis responsivity in mid-adolescence did not serve as a biological marker for psychopathic personality traits among young adults from the general population.

Effects of early-life stress on probabilistic reversal learning and response perseverance in young adults

Early life stress (ELS), including experiences with abuse and neglect, are related to several negative health outcomes in adulthood. One area that has received attention is the increased rate of substance abuse disorder in individuals who had experienced ELS. Given the critical role habitual behavior in the development of substance abuse, ELS may affect the trajectory of neural development such that habitual responding is more dominant than in individuals who did not experience ELS. Here, we examine learning of a probabilistic classification task (the Weather Prediction Task) in healthy young adults who reported significant ELS and those that did not. This task can be learned in a declarative, model-based manner, or in a more habitual, stimulus-response manner. Participants learned to choose the outcome (sun or rain) that was probabilistically associated with each cue combination through reinforcement on each trial. After 100 trials, the probabilities were reversed, and we conceptualized habitual behavior as perseverating responses based on the old probabilities. We also collected information about subjective socio-economic status (sSES), anxiety, depression, and substance use from participants. Using multiple regression, we found that our measure of habitual responding was correlated with reported alcohol use, suggesting that our measure of habit has validity for health behaviors. Furthermore, we found that some forms of early life stress led to greater response perseverance after contingencies were reversed. Overall, the results suggest that childhood adversity may contribute to the development of habit.

A case of central adrenocortical insufficiency with alexithymia and alexisomia

The patient was a 27-year-old woman. Following physical examination for unconscious hypoglycemia, the patient was diagnosed with central adrenocortical insufficiency. She also had alexithymia and alexisomia. Alexisomia is the inability to recognize or describe bodily sensations. Alexithymia is the difficulty of expressing one's feelings adequately. Alexisomia can be described as impaired interoceptive awareness. She had been maltreated and emotionally abused by her parents; thus, her upbringing may have influenced the development of alexithymia and alexisomia. In addition, her upbringing may have influenced the reduced hypothalamus-pituitary-adrenal axis activity. Her failure to perceive hypoglycemic symptoms as hypoglycemia was thought to have been influenced by her alexisomia. Interestingly, her alexisomia improved with steroid replacement therapy; however, the underlying mechanism remains unclear. However, exogenous steroids can also affect interoception. The patient was diagnosed with central adrenocortical insufficiency, an endocrine disorder, suggesting that psychosomatic factors may have been related to the patient's growth history.

Physiological reactivity to acute mental stress in essential hypertension-a systematic review

Objective

Exaggerated physiological reactions to acute mental stress (AMS) are associated with hypertension (development) and have been proposed to play an important role in mediating the cardiovascular disease risk with hypertension. A variety of studies compared physiological reactivity to AMS between essential hypertensive (HT) and normotensive (NT) individuals. However, a systematic review of studies across stress-reactive physiological systems including intermediate biological risk factors for cardiovascular diseases is lacking.

Methods

We conducted a systematic literature search (PubMed) for original articles and short reports, published in English language in peer-reviewed journals in November and December 2022. We targeted studies comparing the reactivity between essential HT and NT to AMS in terms of cognitive tasks, public speaking tasks, or the combination of both, in at least one of the predefined stress-reactive physiological systems.

Results

We included a total of 58 publications. The majority of studies investigated physiological reactivity to mental stressors of mild or moderate intensity. Whereas HT seem to exhibit increased reactivity in response to mild or moderate AMS only under certain conditions (i.e., in response to mild mental stressors with specific characteristics, in an early hyperkinetic stage of HT, or with respect to certain stress systems), increased physiological reactivity in HT as compared to NT to AMS of strong intensity was observed across all investigated stress-reactive physiological systems.

Conclusion

Overall, this systematic review supports the proposed and expected generalized physiological hyperreactivity to AMS with essential hypertension, in particular to strong mental stress. Moreover, we discuss potential underlying mechanisms and highlight open questions for future research of importance for the comprehensive understanding of the observed hyperreactivity to AMS in essential hypertension.

Ultrathin, Soft, Bioresorbable Organic Electrochemical Transistors for Transient Spatiotemporal Mapping of Brain Activity

A critical challenge lies in the development of the next-generation neural interface, in mechanically tissue-compatible fashion, that offer accurate, transient recording electrophysiological (EP) information and autonomous degradation after stable operation. Here, an ultrathin, lightweight, soft and multichannel neural interface is presented based on organic-electrochemical-transistor-(OECT)-based network, with capabilities of continuous high-fidelity mapping of neural signals and biosafety active degrading after performing functions. Such platform yields a high spatiotemporal resolution of 1.42 ms and 20 µm, with signal-to-noise ratio up to ≈37 dB. The implantable OECT arrays can well establish stable functional neural interfaces, designed as fully biodegradable electronic platforms in vivo. Demonstrated applications of such OECT implants include real-time monitoring of electrical activities from the cortical surface of rats under various conditions (e.g., narcosis, epileptic seizure, and electric stimuli) and electrocorticography mapping from 100 channels. This technology offers general applicability in neural interfaces, with great potential utility in treatment/diagnosis of neurological disorders.

Childhood maltreatment disrupts HPA-axis activity under basal and stress conditions in a dose-response relationship in children and adolescents

BACKGROUND

This study investigates the impact of childhood maltreatment (CM) on hypothalamic-pituitary-adrenal (HPA)-axis functioning and on anxiety perception. Moreover, the influence of CM severity and frequency was also explored.

METHODS

In total, 187 participants aged 7-17 were assessed for CM history using validated questionnaires and ad hoc interviews to be classified according to the criteria of the Tool for Assessing the Severity of Situations in which Children are Vulnerable (TASSCV). Psychopathology was ascertained using the K-SADS-PL5. To assess HPA-axis functioning, salivary cortisol samples were collected throughout a normal day and during an acute psychosocial stressor, the Trier Social Stress Test for children (TSST-C). Subjective anxiety was evaluated using STAI/-C.

RESULTS

Youth with a CM history had higher overall diurnal cortisol levels (p = 0.001), blunted cortisol response to acute psychosocial stress (p = 0.002) and greater perceived anxiety (p = 0.003), than those without CM. Specifically, participants exposed to moderate/severe or often/frequent CM showed the greater diurnal cortisol output (p_severity = 0.002; p_frequency = 0.003), and blunted cortisol response during the TSST-C (p_severity = 0.006; p_frequency = 0.008). Meanwhile, youth with low CM severity/frequency exhibited a similar cortisol response to those without CM. However, perceived anxiety was higher in those exposed to CM (p < 0.001), regardless of its severity/frequency.

CONCLUSIONS

Disturbances in HPA-axis functioning are already evident early after CM exposure, while psychological and physiological responses to an acute stressor are dissociated in youth exposed to CM. The dose-response relationship described in this paper highlights the need to comprehensively evaluate CM so that vulnerable children can be identified and assigned to proper interventions.

Neuroendocrine System Adaptation during Consecutive Extrinsic Stimuli: A Pilot Dynamic Study

This pilot repeated measures study aims to evaluate the dynamics of the autonomic nervous system (ANS), the hypothalamic-pituitary-adrenal (HPA) axis, and/or their interplay with low-level inflammation in healthy schoolchildren during consecutive extrinsic stimuli. Twenty healthy schoolchildren and adolescents aged 11-14 years (12.5 ± 1.5) were consecutively exposed to an oral task (#2) and an arithmetic task (#3) (Trier Social Stress Test for Children (TSST-C)), lasting 5 min each, and a three-minute cellular phone call (#4). Salivary cortisol (SC) was sampled at baseline (#1) and immediately after each exposure (#2, 3, and 4). Baseline serum high-sensitivity C-reactive protein (hsCRP) and cortisol levels were also assessed. ANS dynamics and complexity were measured using Sample Entropy (SampEn) at each experimental time period (#1-4). Baseline serum hCRP and cortisol correlated negatively to each other, while the ANS and HPA axis acute reactions to the three consecutive stimuli differed over time. The ANS adaptation to these stimuli included complexity modulation, which was not dependent on baseline hsCRP or cortisol, and weakened during the third stimulation. However, baseline hsCRP and cortisol had a weakening and an increasing effect on the HPA axis over time, respectively. We conclude that low-level inflammation and baseline morning cortisol level have no effect on ANS dynamics but influence the HPA axis response to consecutive external stimuli.

Physiological and affective responses to green space virtual reality among pregnant women

BACKGROUND

Benefits of green spaces on stress reduction have been shown in previous studies. Most existing studies to date have focused on the general population. However, there is a lack of understanding of physiological mechanisms underlying the beneficial effects of green space among special populations, such as pregnant women.

OBJECTIVES

To examine physiological and affective responses to green space on stress recovery among pregnant women, using simulated green space exposure through virtual reality (VR).

METHODS

We recruited 63 pregnant women between 8 and 14 weeks' gestational age for a laboratory experiment. Participants were randomly assigned to view one of three, 5-min, VR videos of an urban scene with different green space levels (i.e., non-green, moderate, and high) after a laboratory stressor, the Trier Social Stress Test. Physiological stress responses were measured via changes in blood pressure, heart rate, skin conductance level, salivary alpha-amylase, and salivary cortisol. Affective response was measured using the Positive and Negative Affect Scale.

RESULTS

We found that visual exposure to a green space environment in VR was associated with both physiological and affective stress reduction among pregnant women, including lower systolic blood pressure [-4.6 mmHg, 95% confidence interval (CI): -8.8, -0.4], reduced salivary alpha-amylase concentration (-1.2 ng/ml, 95% CI: -2.2, -0.2), improved overall positive affect (score: 6.6, 95% CI: 0.3, 13.0) and decreased negative affect of anxiety (score: -2.6, 95% CI: -5.19, -0.04) compared to non-green space environment. Exposure to high green space environment in park-like setting had the strongest impacts on stress recovery.

CONCLUSION

This study demonstrated that virtual green space exposure could effectively ease stress and improve mental health and well-being during pregnancy. Even a short immersion in VR-based green space environment may bring health benefits, which has significant implications for pregnant women when access to an actual nature may not be possible.

Is stress colorblind? Exploring endocrine stress responses in intergroup contexts using a virtual reality-based Trier Social Stress Test (TSST-VR)

Are social stress reactions dependent on the group identities of interaction partners? This study explored the role of ethnic context in modulating endocrine stress responses using a virtual reality (VR)-based adaptation of a standardized stress induction protocol, the Trier Social Stress Test (TSST-VR). Previous research found no clear link between endocrine stress response and ethnic context in the TSST, but conclusions remain limited due to the quasi-experimental nature of manipulating ethnic context in real-life face-to-face interactions. The VR adaptation of the TSST circumvents quasi-experimental limitations and thus provides a first, randomized-controlled investigation of the effects of ethnic context on endocrine stress responses. Forty-three men participated in the study, facing either an ingroup ("White") or an outgroup ("Arab") panel of interviewers. As expected, the TSST-VR produced physiological and subjective stress reactions. However, endocrine stress reactions occurred independent of interviewer ethnicity and could not be predicted based on implicit bias, explicit prejudice, or prejudice-related appearance concerns. Other physiological and subjective stress reactivity parameters also remained comparable across intergroup conditions. Implications for stress research are discussed.

Hunting for Genes Underlying Emotionality in the Laboratory Rat: Maps, Tools and Traps

Scientists have systematically investigated the hereditary bases of behaviors since the 19th century, moved by either evolutionary questions or clinically-motivated purposes. The pioneer studies on the genetic selection of laboratory animals had already indicated, one hundred years ago, the immense complexity of analyzing behaviors that were influenced by a large number of small-effect genes and an incalculable amount of environmental factors. Merging Mendelian, quantitative and molecular approaches in the 1990s made it possible to map specific rodent behaviors to known chromosome regions. From that point on, Quantitative Trait Locus (QTL) analyses coupled with behavioral and molecular techniques, which involved in vivo isolation of relevant blocks of genes, opened new avenues for gene mapping and characterization. This review examines the QTL strategy applied to the behavioral study of emotionality, with a focus on the laboratory rat. We discuss the challenges, advances and limitations of the search for Quantitative Trait Genes (QTG) playing a role in regulating emotionality. For the past 25 years, we have marched the long journey from emotionality-related behaviors to genes. In this context, our experiences are used to illustrate why and how one should move forward in the molecular understanding of complex psychiatric illnesses. The promise of exploring genetic links between immunological and emotional responses are also discussed. New strategies based on humans, rodents and other animals (such as zebrafish) are also acknowledged, as they are likely to allow substantial progress to be made in the near future.

Stress and surgical diseases of thyroid gland in environment of the armed conflict (review of literature and own observations)

Stress and surgical diseases of thyroid gland in environment of the armed conflict (review of literature and own observations)

Applying minimally invasive biomarkers of chronic stress across complex ecological contexts

Chronic stress is both theoretically and methodologically challenging to operationalize through biomarkers. Yet minimally invasive, field-friendly biomarkers of chronic stress are valuable in research linking biology and culture, seeking to understand differential patterns of human development across ecological contexts, and exploring the evolution of human sociality. For human biologists, a central question in measurement and interpretation of biomarkers is how stress-responsive physiological systems are regulated across diverse human ecologies. This article aims to describe a conditional toolkit for human biologists interested in the study of chronic stress, highlighting a mix of longstanding and novel biomarkers, with special focus on hair/fingernail cortisol, latent herpesvirus antibodies, allostatic load indices, and serial/ambulatory data collection approaches. Future trends in chronic stress biomarker research, including epigenetic approaches, are briefly considered. This overview considers: (1) challenges in separating a distinctly psychosocial dimension of chronic stress from adversity more broadly; (2) essential characteristics of human ecology that shape interpretation; (3) retrospective vs. longitudinal sampling; (4) the role of age, developmental effects, and local biologies; (5) different timescales of chronicity; and (6) the role of culture.

The cortisol awakening response at admission to hospital predicts depression severity after discharge in major depressive disorder patients—A replication study

The cortisol awakening response (CAR) is a non-invasive biomarker for hypothalamic-pituitary-adrenal axis (HPA) dysregulation, reflecting accumulated stress over time. In a previous study we reported that a blunted CAR before an inpatient treatment predicted self-reported depressive symptoms six weeks and six months after discharge [Eikeseth, F. F., Denninghaus, S., Cropley, M., Witthöft, M., Pawelzik, M., &amp; Sütterlin, S. (2019). The cortisol awakening response at admission to hospital predicts depression severity after discharge in major depressive disorder (MDD) patients. Journal of Psychiatric Research, 111, 44-50)]. This replication study adopted an improved overall methodology with more stringent assessment protocols and monitoring. The longitudinal design included 122 inpatients from a psychosomatic hospital with a diagnosis of MDD displaying symptoms of moderate to severe major depression (n = 80 females). The CAR was measured at intake. Depression severity was assessed as Beck Depression Inventory II scores at intake, discharge, 6 weeks and 6 months following discharge. Results from the original study were replicated in terms of effect size but did not reach statistical significance (correlation between BDI-II 6 months after discharge and AUCg: r = −0.213; p = 0.054). The replication study yielded nearly identical correlation coefficients as in the original study (BDI-II 6 months and CAR, r = −0.223, p &lt; 0.05). The replication of previously reported effect sizes with a concurrent lack of statistical significance in the more restrictive, larger and better controlled replication study may well inform research on psycho-endocrinological predictors for treatment success, but suggests a rather limited practical relevance for cortisol awakening response measures in this clinical context.

The combined effects of corticosterone and brain-derived neurotrophic factor on plasticity-related receptor phosphorylation and expression at the synaptic surface in male Sprague-Dawley rats

Following acute exercise, a temporal window exists wherein neuroplasticity is thought to be heightened. Although a number of studies have established that pairing this post-exercise period with motor training enhances learning, the mechanisms through which exercise-induced priming occurs are not well understood. Previously, we characterized a rodent model of acute exercise that generates significant enhancement in glutamatergic receptor phosphorylation as a possible mechanism to explain how exercise-induced priming might occur. However, whether these changes are stimulated by peripheral factors (e.g., glucocorticoids), central effects (e.g., brain-derived neurotrophic factor (BDNF), or a combination of the two remains unclear. Herein, we explored the possible individual and/or cumulative contribution corticosterone (CORT) and BDNF may have on glutamate receptor phosphorylation and synaptic surface expression. Tissue slices from the sensorimotor cortex were prepared and acutely (30 min) incubated with either CORT (200 nM), BDNF (20 ng/mL), or the simultaneous application of CORT and BDNF (CORT+BDNF). Immunoblotting with biotinylated synaptoneurosomes (which provide an enrichment of proteins from the synaptic surface) suggested divergent effects between CORT and BDNF. Acute CORT application enhanced NMDA- (GluN2A, B) and AMPA- (GluA1) receptor phosphorylation, whereas BDNF preferentially increased synaptic surface expression of both NMDA- and AMPA-receptor subunits. The combined effects of CORT+BDNF resulted in a unique subset of signaling patterns that favored phosphorylation in the absence of surface expression. Taken together, these data provide a mechanistic framework for how CORT and BDNF may alter glutamatergic synapses during exercise-induced priming.

Psychosocial Stress and Hypothalamic-Pituitary-Adrenal Axis Stress Reactivity: Variations by Race and Socioeconomic Status Among Adults at Risk of Diabetes

OBJECTIVE

Although stress is posited to play a key role in health disparities, the extent to which commonly used self-report psychosocial stress measures are related to neurobiological stress processes, especially across diverse populations, is unresolved. This study examined how two measures of psychosocial stress, perceived stress and domain-specific stress, covary with the acute neurobiological stress response.

METHODS

The Richmond Stress and Sugar Study includes a racially and socioeconomically diverse cohort of adults at risk for type 2 diabetes ( n = 125; mean age = 57 years, 48% Black, and 61% high neighborhood socioeconomic status [SES]). Hypothalamic-pituitary-adrenal axis reactivity was assessed by salivary cortisol response to the Trier Social Stress Test (TSST), a laboratory stressor.

RESULTS

Higher perceived stress was associated with a lower cortisol response to the TSST (-7.5%; 95% confidence interval [CI] = -13.1% to -1.5%) but was not associated with cortisol recovery after the TSST (3%; 95% CI = -0.6% to 6.8%). In contrast, domain-specific stress was not associated with cortisol response (-2.1%; 95% CI = -20.7% to 20.9%) but was inversely associated with cortisol recovery (3.7%; 95% CI = 0.6% to 7.0%). SES modified these associations: both perceived stress and domain-specific stress were associated with TSST cortisol response only among participants from high-SES neighborhoods. There was minimal evidence of effect modification by race.

CONCLUSIONS

Both self-report measures of psychosocial stress were associated with hypothalamic-pituitary-adrenal axis reactivity to an acute stressor. These associations varied by perceived versus domain-specific measurement scales and by neighborhood SES. Further efforts to refine stress measures and clarify biological linkages between social status and health are needed.

Impacts of Landscape Type, Viewing Distance, and Permeability on Anxiety, Depression, and Stress

Contact with nature is beneficial for mental health, including anxiety and stress. Exposure to virtual nature also has similar restorative traits with real nature. However, previous studies on the restorative environment mostly focus on ordinary people while caring less about patients with depressive disorders. Thus, the restorative impacts of virtual nature on patients with depression warrant examination. This research aims to study the restorative effects of virtual reality (VR) landscape type, viewing distance, and permeability on anxiety, depression, and stress in patients with depression. Study A revealed that the perceived restorative level of landscape type varies greatly: grassland > forest > water > undergrowth > urban square. Additionally, natural environments with higher openness, more green elements, more blue sky, and more sunshine exposure had higher restorative levels on perceived depression, anxiety, and stress relief. Study B found that the grassland landscape with a higher viewing distance and a medium vegetation edge permeability provides more restorative impacts for patients with depression.

Real sweating in a virtual stress environment: Investigation of the stress reactivity in people with primary focal hyperhidrosis

Background

Hyperhidrosis (excessive sweating, OMIM %114110) is a complex disorder with multifactorial causes. Emotional strains and social stress increase symptoms and lead to a vicious circle. Previously, we showed significantly higher depression scores, and normal cortisol awakening responses in patients with primary focal hyperhidrosis (PFH). Stress reactivity in response to a (virtual) Trier Social Stress Test (TSST-VR) has not been studied so far. Therefore, we measured sweat secretion, salivary cortisol and alpha amylase (sAA) concentrations, and subjective stress ratings in affected and non-affected subjects in response to a TSST-VR.

Method

In this pilot study, we conducted TSST-VRs and performed general linear models with repeated measurements for salivary cortisol and sAA levels, heart rate, axillary sweat and subjective stress ratings for two groups (diagnosed PFH (n = 11), healthy controls (n = 16)).

Results

PFH patients showed significantly heightened sweat secretion over time compared to controls (p = 0.006), with highest quantities during the TSST-VR. In both groups, sweating (p < 0.001), maximum cortisol levels (p = 0.002), feelings of stress (p < 0.001), and heart rate (p < 0.001) but not sAA (p = 0.068) increased significantly in response to the TSST-VR. However, no differences were detected in subjective ratings, cortisol concentrations and heart rate between PFH patients and controls (p_all > 0.131).

Conclusion

Patients with diagnosed PFH showed stress-induced higher sweat secretion compared to healthy controls but did not differ in the stress reactivity with regard to endocrine or subjective markers. This pilot study is in need of replication to elucidate the role of the sympathetic nervous system as a potential pathway involved in the stress-induced emotional sweating of PFH patients.

Child maltreatment and hypothalamic-pituitary-adrenal axis functioning: A systematic review and meta-analysis

Alterations in hypothalamic-pituitary-adrenal (HPA) axis and its effector hormone cortisol have been proposed as one possible mechanism linking child maltreatment experiences to health disparities. In this series of meta-analyses, we aimed to quantify the existing evidence on the effect of child maltreatment on various measures of HPA axis activity. The systematic literature search yielded 1,858 records, of which 87 studies (k = 132) were included. Using random-effects models, we found evidence for blunted cortisol stress reactivity in individuals exposed to child maltreatment. In contrast, no overall differences were found in any of the other HPA axis activity measures (including measures of daily activity, cortisol assessed in the context of pharmacological challenges and cumulative measures of cortisol secretion). The impact of several moderators (e.g., sex, psychopathology, study quality), the role of methodological shortcomings of existing studies, as well as potential directions for future research are discussed.

The Embodiment of Insult: A Theory of Biobehavioral Response to Workplace Incivility

This article builds a broad theory to explain how people respond, both biologically and behaviorally, when targeted with incivility in organizations. Central to our theorizing is a multifaceted framework that yields four quadrants of target response: reciprocation, retreat, relationship repair, and recruitment of support. We advance the novel argument that these behaviors not only stem from biological change within the body but also stimulate such change. Behavioral responses that revolve around affiliation and produce positive social connections are most likely to bring biological benefits. However, social and cultural features of an organization can stand in the way of affiliation, especially for employees holding marginalized identities. When incivility persists over time and employees lack access to the resources needed to recover, we theorize, downstream consequences can include harms to their physical health. Like other aspects of organizational life, this biobehavioral theory of incivility response is anything but simple. But it may help explain how seemingly "small" insults can sometimes have large effects, ultimately undermining workforce well-being. It may also suggest novel sites for incivility intervention, focusing on the relational and inclusive side of work. The overarching goal of this article is to motivate new science on workplace incivility, new knowledge, and ultimately, new solutions.

The neuroendocrinology of stress: Glucocorticoid signaling mechanisms

Glucocorticoid signaling plays major roles in energy homeostasis and adaptation to adversity, and dysregulation of this process is linked to systemic and psychological pathology. Over the last several decades, new work has challenged many of the long-standing assumptions regarding regulation of glucocorticoid secretion and glucocorticoid signaling mechanisms, revealing an exquisite complexity that accompanies the important and perhaps global role of these hormones in physiological and psychological regulation. New findings have included discovery of membrane signaling, direct neural control of the adrenal, a role for pulsatile glucocorticoid release in glucocorticoid receptor signaling, marked sex differences in brain glucocorticoid biology, and salutary as well as deleterious roles for glucocorticoids in long- and short-term adaptations to stress. This review covers some of the major lessons learned in the area of mechanisms of glucocorticoid signaling, and discusses how these may inform the field moving forward.

Hair cortisol levels in women with medically unexplained symptoms

Stress has been demonstrated to be involved in the development of medically unexplained symptoms. A key underlying mechanism could be lower levels of cortisol, which can contribute to symptoms such as fatigue or pain. However, the literature is highly equivocal, which may be due to methodological limitations inherent in short-term cortisol assessment. The aim of this case-control study was to investigate, for the first time, whether individuals with different forms of medically unexplained symptoms show altered hair cortisol concentrations, a long-term marker of hypothalamic-pituitary-adrenal functioning. Two groups of women with medically unexplained symptoms were recruited. The first had a functional somatic syndrome, characterised by specific medically unexplained symptoms (i.e., chronic fatigue syndrome, fibromyalgia, or irritable bowel syndrome, n = 33). The second had somatic symptom disorder, characterised by excessive thoughts, feelings, and behaviours devoted to various medically unexplained symptoms (n = 23). These groups were contrasted with healthy controls (n = 30), and women with depression (n = 27). Cortisol representing the previous three months was extracted from hair. Chronic stress and childhood trauma were assessed (retrospectively). Women with somatic symptom disorder had lower hair cortisol than healthy controls and women with functional somatic syndromes. No differences in hair cortisol were found between healthy controls, functional somatic syndromes, and depression. Neither childhood trauma nor chronic stress was correlated with hair cortisol. Provided that our findings are replicated, they may suggest that hypocortisolism is found in a specific subgroup of individuals with medically unexplained symptoms, and potentially in those characterised by excessive thoughts, feelings, and behaviours about symptoms.

Stress research during the COVID-19 pandemic and beyond

The COVID-19 pandemic confronts stress researchers in psychology and neuroscience with unique challenges. Widely used experimental paradigms such as the Trier Social Stress Test feature physical social encounters to induce stress by means of social-evaluative threat. As lockdowns and contact restrictions currently prevent in-person meetings, established stress induction paradigms are often difficult to use. Despite these challenges, stress research is of pivotal importance as the pandemic will likely increase the prevalence of stress-related mental disorders. Therefore, we review recent research trends like virtual reality, pre-recordings and online adaptations regarding their usefulness for established stress induction paradigms. Such approaches are not only crucial for stress research during COVID-19 but will likely stimulate the field far beyond the pandemic. They may facilitate research in new contexts and in homebound or movement-restricted participant groups. Moreover, they allow for new experimental variations that may advance procedures as well as the conceptualization of stress itself. While posing challenges for stress researchers undeniably, the COVID-19 pandemic may evolve into a driving force for progress eventually.

Habituation of salivary cortisol and cardiovascular reactivity to a repeated real-life and virtual reality Trier Social Stress Test

BACKGROUND

Although the Trier Social Stress Test (TSST) constitutes a valid paradigm for social stress induction, less is known about the effects of a virtual reality (VR) TSST on short- and long-term hypothalamic-pituitary-adrenal (HPA) axis and sympathetic-adreno-medullar (SAM) axis responses. Hence, this study set out to evaluate reactivity and habituation of self-reported stress and HPA and SAM reactivity in a real TSST and VR-TSST when compared to a placebo TSST.

METHOD

Sixty-eight healthy young adults (50% female) were randomly assigned to either a real TSST, a VR-TSST, or a placebo TSST, all of which were conducted three times (one day and one week post initial exposure). Social presence, self-reported stress, salivary cortisol, heart rate (HR), and heart rate variability (HRV) were analyzed using ANOVAs and multilevel models.

FINDINGS

On the first exposure, both the real and VR-TSST showed significantly stronger cortisol and cardiovascular responses than the placebo. On the second visit, the cortisol response was still significantly high-and the HRV response low-for the real and VR-TSST. The third visit resulted in HR, HRV, and cortisol responses comparable to the placebo group. Furthermore, the real TSST induced more self-reported stress than the placebo on all three visits, the VR-TSST only on the first two visits. Social presence was stable across conditions and had no association with stress markers.

CONCLUSION

These findings imply that the replicability of stress exposures at shorter intervals seems problematic for the traditional TSST, and for the VR-TSST.

Role of NR3C1 and SLC6A4 methylation in the HPA axis regulation in burnout

BACKGROUND

Work-related stress and burnout have become major occupational health concerns. Dysregulation of HPA axis is considered one of the central mechanisms and is potentially moderated through epigenetics. In the present study, we aim to investigate epigenetic regulation of the HPA axis in burnout, by focusing on salivary cortisol and cortisone and DNA methylation of the glucocorticoid receptor gene (NR3C1) and the serotonin transporter gene (SLC6A4).

METHODS

We conducted a cross-sectional study with 59 subjects with burnout and 70 healthy controls recruited from the general population. All participants underwent a clinical interview and psychological assessment. Saliva samples were collected at 0, 30 and 60 min after awakening and were used to quantify cortisol and cortisone. Pyrosequencing was performed on whole blood-derived DNA to assess DNA methylation.

RESULTS

There were no between-group differences in cortisol levels, whereas burnout participants had higher levels of cortisone. Job stress was associated with increased cortisol and cortisone. We observed both increased and decreased NR3C1 and SLC6A4 methylation in the burnout group compared to the control group. Some of these methylation changes correlated with burnout symptoms dimensionally. Increased methylation in a specific CpG in the SLC6A4 promoter region moderated the association between job stress and burnout. DNA methylation in this CpG was also associated with increased cortisol. In addition, average methylation of NR3C1 was negatively associated with cortisone levels.

LIMITATIONS

This is a cross-sectional study and therefore no conclusions on causality could be made.

CONCLUSIONS

We provide first evidence of changes in DNA methylation of NR3C1 and SLC6A4 in burnout, which were further associated with cortisol and cortisone. Further, increased cortisol and cortisone seemed to reflect job stress rather than burnout itself.

Social and Biological Transgenerational Underpinnings of Adolescent Pregnancy

Adolescent pregnancy (occurring < age 20) is considered a public health problem that creates and perpetuates inequities, affecting not only women, but societies as a whole globally. The efficacy of current approaches to reduce its prevalence is limited. Most existing interventions focus on outcomes without identifying or addressing upstream social and biological causes. Current rhetoric revolves around the need to change girls' individual behaviours during adolescence and puberty. Yet, emerging evidence suggests risk for adolescent pregnancy may be influenced by exposures taking place much earlier during development, starting as early as gametogenesis. Furthermore, pregnancy risks are determined by complex interactions between socio-structural and ecological factors including housing and food security, family structure, and gender-based power dynamics. To explore these interactions, we merge three complimentary theoretical frameworks: "Eco-Social", "Life History" and "Developmental Origins of Health and Disease". We use our new lens to discuss social and biological determinants of two key developmental milestones associated with age at first birth: age at girls' first menstrual bleed (menarche) and age at first sexual intercourse (coitarche). Our review of the literature suggests that promoting stable and safe environments starting at conception (including improving economic and social equity, in addition to gender-based power dynamics) is paramount to effectively curbing adolescent pregnancy rates. Adolescent pregnancy exacerbates and perpetuates social inequities within and across generations. As such, reducing it should be considered a key priority for public health and social change agenda.

Neural signature of affective but not cognitive self-regulation predicts cortisol response to psychosocial stress

Self-regulation is theoretically closely related to coping with stressful events, yet whether self-regulation capacities can predict individual stress responses is largely unknown. Cognitive control and emotion regulation are two major aspects involved in self-regulation, both of which are mechanisms to support goal-directed behaviors. Here, we aimed to elucidate whether the neural processes involved in emotion regulation and cognitive control could predict the cortisol response to stress. Therefore, we recorded first electroencephalography (EEG) during a cognitive conflict task (Simon task) and an emotion regulation task (cognitive reappraisal and expressive suppression) before healthy participants (n = 72) underwent a psychosocial stressor. Our results showed that late positive potentials (LPPs) during the emotion regulation task predicted both cortisol reactivity to and recovery from stress. Cognitive control and its neural underpinning, however, did not predict the individual stress response. These findings indicate that neural emotion regulation processes can predict HPA axis response to stress, and suggest a differential involvement of cognitive and affective components of self-regulation in the adaptation to stressful events.

Impact of stress resilience and susceptibility on fear learning, anxiety, and alcohol intake

Post-traumatic stress disorder (PTSD) can develop after exposure to traumatic events and severely impacts the quality of life. PTSD is frequently comorbid with substance use disorders, with alcoholism being particularly common. However, not everyone who experiences trauma develops PTSD and the factors that render individuals susceptible or resilient to the effects of stress are unknown although gender appears to play an important role. Rodent models of stress exposure such as stress-enhanced fear learning (SEFL) recapitulate some aspects of PTSD symptomology, making them an invaluable tool for studying this disorder. This study examined whether exposure to a modified version of the SEFL procedure (4 footshocks instead of the standard 15 over 90 min) would reveal both susceptible and resilient subjects. Following stress exposure, distinct susceptible and resilient groups emerged that differed in fear learning and anxiety-related behavior as well as voluntary alcohol intake. Some aspects of stress susceptibility manifested differently in males compared to females, with susceptibility associated with increased alcohol intake in males and increased baseline anxiety in females.

How Do People Cope During the COVID-19 Pandemic and Stay Well? A Salutogenic Longitudinal Study in Israel

Employing the salutogenic approach, this longitudinal study explored the effects of coping with the COVID-19 pandemic in Israel, as it evolved from an acute to a chronic stress situation, during the first year. We examined the role of individual [sense of coherence (SOC)], social (perceived social support), and national [sense of national coherence (SONC)] coping resources, as well as situational and demographic factors, in predicting mental health and anxiety. Data was collected in five phases between March 2020 and February 2021 via a repeated panel sample and included 198 Jewish Israelis (52% males) age 18-64 (M = 43.5). The results confirmed the expected pattern of moving from acute to chronic stressful situation: levels of general anxiety were higher in the first phase of the pandemic outbreak as compared to the other phases. Levels of social and national coping resources significantly decreased over time. However, as expected, the salutogenic resource of the individual sense of coherence remained stable and was also found as the main predictor of both anxiety and mental health in the 5 phases of the study. Beyond the explanatory factor of SOC, mental health was better explained by the social and national coping resources, while anxiety was explained by situational factors (level of financial risk and gender). The discussion delineates the longitudinal effects of individual, social, and national coping resources on mental health and anxiety during the dynamic process of the long period of 1 year of the pandemic, evolving from acute to chronic phases of the complicated health, economic, social, and political crisis.

Glucocorticoid Receptor Signaling in Diabetes

Stress and depression increase the risk of Type 2 Diabetes (T2D) development. Evidence demonstrates that the Glucocorticoid (GC) negative feedback is impaired (GC resistance) in T2D patients resulting in Hypothalamic-Pituitary-Adrenal (HPA) axis hyperactivity and hypercortisolism. High GCs, in turn, activate multiple aspects of glucose homeostasis in peripheral tissues leading to hyperglycemia. Elucidation of the underlying molecular mechanisms revealed that Glucocorticoid Receptor (GR) mediates the GC-induced dysregulation of glucose production, uptake and insulin signaling in GC-sensitive peripheral tissues, such as liver, skeletal muscle, adipose tissue, and pancreas. In contrast to increased GR peripheral sensitivity, an impaired GR signaling in Peripheral Blood Mononuclear Cells (PBMCs) of T2D patients, associated with hyperglycemia, hyperlipidemia, and increased inflammation, has been shown. Given that GR changes in immune cells parallel those in brain, the above data implicate that a reduced brain GR function may be the biological link among stress, HPA hyperactivity, hypercortisolism and hyperglycemia. GR polymorphisms have also been associated with metabolic disturbances in T2D while dysregulation of micro-RNAs—known to target GR mRNA—has been described. Collectively, GR has a crucial role in T2D, acting in a cell-type and context-specific manner, leading to either GC sensitivity or GC resistance. Selective modulation of GR signaling in T2D therapy warrants further investigation.

Is the Association Between Education and Sympathovagal Balance Mediated by Chronic Stressors?

Background

This study investigated whether raised chronic stress in low education groups contributes to education differences in cardiovascular disease by altering sympathovagal balance.

Methods

This study included cross-sectional data of 10,202 participants from the multi-ethnic, population-based HELIUS-study. Sympathovagal balance was measured by baroreflex sensitivity (BRS), the standard deviation of the inter-beat interval (SDNN) and the root mean square of successive differences between normal heartbeats (RMSSD). The associations between chronic stressors (work, home, psychiatric, financial, negative life events, lack of job control and perceived discrimination) in a variety of domains and BRS, SDNN and RMSSD were assessed using linear regression, adjusted for age, ethnicity, waist-to-hip ratio and pack-years smoked. Mediation analysis was used to assess the contribution of chronic stress to the association between education and sympathovagal balance.

Results

Modest but significant associations were observed between financial stress and BRS and SDNN in women, but not in RMSSD nor for any outcome measure in men. Women with the highest category of financial stress had 0.55% lower BRS (ms/mmHg; β = -0.055; CI = -0.098, -0.011) and 0.61% lower SDNN (ms; β = -0.061; CI = -0.099, -0.024) than those in the lowest category. Financial stress in women contributed 7.1% to the association between education and BRS, and 13.8% to the association between education and SDNN.

Conclusion

No evidence was found for the hypothesized pathway in which sympathovagal balance is altered by chronic stress, except for a small contribution of financial stress in women.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12529-021-10027-9.

T3 is linked to stress-associated reduction of prolactin in lactating women

The relationship between stress responses and lactation is bidirectional. Breastfeeding confers many benefits to maternal health, including attenuated hypothalamic-pituitary-adrenal axis responsiveness to stress. However, increased stress burden can impair lactation. The mechanisms that underlie these relationships are poorly understood. The present study aimed to compare breastfeeding habits, as well as subjective and objective measures of stress, in employed and non-employed lactating women and assess the relationships between these measures and prolactin (PRL), thyroid hormones (thyroid-stimulating hormone, triiodothyronine [T3] and thyroxine), vasopressin and cortisol levels. A dexamethasone suppression test was also administered to determine the sensitivity of the hypothalamic-pituitary-adrenal axis to negative-feedback. We report that lactating employed women had lower breastfeeding rates and lower PRL than lactating non-employed women. They also had a significantly higher stress burden, indicated by elevations in blood pressure and evening cortisol, relative to lactating non-employed women. In regression analyses that controlled for feeding modality and breastfeeding duration, we found these factors differentially affected PRL in the two groups and there were significant differences in PRL across groups that were not accounted for by these factors. A mediation regression analysis suggested that group differences in PRL were best explained by differences in T3 and income levels, rather than breastfeeding duration or other variables. Our data fit a speculative model in which elevated maternal stress increases cortisol, which suppresses T3, leading to decreased PRL. The decreases in PRL are associated with higher rates of bottlefeeding, which may further contribute to decreased PRL.

Brain preparedness: The proactive role of the cortisol awakening response in hippocampal-prefrontal functional interactions

Upon awakening from nighttime sleep, the stress hormone cortisol in humans exhibits a robust rise within thirty to forty-five minutes. This cortisol awakening response (CAR), a crucial point of reference within the healthy cortisol circadian rhythm, has been linked to various psychological, psychiatric and health-related conditions. The CAR is thought to prepare the brain for anticipated challenges of the upcoming day to maintain one's homeostasis and promote adaptive responses. Using brain imaging with a prospective design and pharmacological manipulation, we investigate the neurobiological mechanisms underlying this preparation function of the CAR across two studies. In Study 1, a robust CAR is predictive of less hippocampal and prefrontal activity, though enhanced functional coupling between those regions during a demanding task hours later in the afternoon. Reduced prefrontal activity is in turn linked to better working memory performance, implicating that the CAR proactively promotes brain preparedness based on improved neurocognitive efficiency. In Study 2, pharmacologically suppressed CAR using Dexamethasone mirrors this proactive effect, which further causes a selective reduction of prefrontal top-down functional modulation over hippocampal activity. These findings establish a causal link between the CAR and its proactive role in optimizing functional brain networks involved in neuroendocrine control, executive function and memory.

Salivary cortisol patterns in psychopathic and non-psychopathic offenders

Previous research has described diverse biological correlates of the psychopathic personality. Efforts to understand the underpinnings of low fear responses in psychopathic individuals have drawn attention to the possible role of abnormalities in hypothalamic-pituitary-adrenal (HPA) axis function, but studies to date have been largely limited to youth or to adult community samples. The current study therefore examined morning basal cortisol levels and responses to a psychosocial stress task in a forensic clinical sample of psychopathic offenders (n = 14), non-psychopathic offenders (n = 22), and non-offender controls (n = 14). Morning cortisol levels were similar in all three groups. Throughout the stress task, psychopathic offenders showed significantly lower cortisol than controls; non-psychopathic offenders showed a similar but non-significant trend towards lower cortisol. The three groups did not differ, however, in cortisol response slopes. Implications of these findings are discussed in the framework of current theories about biological mechanisms underlying psychopathic personality.

Impact of Acute and Chronic Cannabis Use on Stress Response Regulation: Challenging the Belief That Cannabis Is an Effective Method for Coping

Although research has only recently started to examine the impact of cannabis use on stress response, there is some evidence that indicates acute and chronic impacts of cannabis on these processes. In this paper, we review processes involved in regulating the stress response and we review the influence of acute and chronic exposure to cannabis on patterns and regulation of the stress response. We also highlight the role of stress as a risk factor for initiation and maintenance of cannabis use. In this context, we examine moderating variables, including sex and life adversity. In light of recent observations indicating increasing prevalence of cannabis use during pregnancy, we provide additional focus on cannabis use in this vulnerable population, including how acute and chronic stress may predispose some individuals to use cannabis during pregnancy. While this line of research is in its infancy, we review available articles that focus on the perinatal period and that examined the association between cannabis use and various life stressors, including partner violence, job loss, and lack of housing. We also review psychiatric co-morbidities (e.g., post-traumatic stress disorder, anxiety). A better understanding of the way stress and cannabis use relate within the general population, as well as within certain subgroups that may be at a greater risk of using and/or at greater risk for adverse outcomes of use, may lead to the development of novel prevention and intervention approaches.

Identifying diurnal cortisol profiles among young adults: Physiological signatures of mental health trajectories

Previous research has used cortisol, the major hormonal byproduct of the hypothalamic pituitary adrenal (HPA) axis system, to explore how environmental stressors influence daily physiological functioning. Most of the research focused on diurnal cortisol has examined specific cortisol markers, with little consideration of how different components of the diurnal pattern may co-occur. Morning level, cortisol awakening response (CAR), bedtime level, as well as the diurnal slope and total cortisol exposure throughout the day (area under the curve; AUC), are five common parameters of diurnal HPA axis functioning that have been individually linked to physical and mental health outcomes, with mixed results. The current study introduces a novel approach to capture heterogeneity in HPA axis activity by using latent profile analysis to generate empirically-derived, theoretically supported diurnal cortisol profiles based on all five indicators. We analyzed salivary cortisol data from 278 young adults during a time of heightened sociopolitical stress - the 2016 U.S. presidential election - and examined whether profiles differentially predicted mental health trajectories across six months. Findings suggest that a specific combination of cortisol parameters (i.e., flat slope, high AUC, and high CAR) may predict worse mental health risk over time. Overall, this work suggests that diurnal cortisol profiles likely reflect distinct physiological underpinnings with unique health consequences that may not be observed by studying individual cortisol parameters.

The Concept of Advanced Multi-Sensor Monitoring of Human Stress

Many people live under stressful conditions which has an adverse effect on their health. Human stress, especially long-term one, can lead to a serious illness. Therefore, monitoring of human stress influence can be very useful. We can monitor stress in strictly controlled laboratory conditions, but it is time-consuming and does not capture reactions, on everyday stressors or in natural environment using wearable sensors, but with limited accuracy. Therefore, we began to analyze the current state of promising wearable stress-meters and the latest advances in the record of related physiological variables. Based on these results, we present the concept of an accurate, reliable and easier to use telemedicine device for long-term monitoring of people in a real life. In our concept, we ratify with two synchronized devices, one on the finger and the second on the chest. The results will be obtained from several physiological variables including electrodermal activity, heart rate and respiration, body temperature, blood pressure and others. All these variables will be measured using a coherent multi-sensors device. Our goal is to show possibilities and trends towards the production of new telemedicine equipment and thus, opening the door to a widespread application of human stress-meters.

Genetic and environmental influences on cortisol reactivity to a psychosocial stressor in adolescents and young adults

Individuals vary in their response to psychological and physiological stressors, and this reactivity can be captured using measures of cortisol. Previous research suggests cortisol reactivity is under some degree of genetic control; however, the measures used have varied widely. This study (N = 524) examined potential differences in heritability across varying cortisol metrics of stress reactivity following the Trier Social Stress Test (TSST) and whether these measures are genetically or environmentally interrelated. Participants included twins aged 15-20 years (56% female). Cortisol reactivity to the TSST was assessed via serial salivary cortisol samples collected pre- and post-TSST. Modest to moderate heritability estimates (12% [95CI: 1-36%] - 45% [95CI: 16-69%]) were observed across measures purported to capture stress reactivity (peak, area under the curve [AUC], baseline-to-peak change). Findings also demonstrate both shared and unique genetic and environmental influences between baseline cortisol and cortisol reactivity. Minimal to no additional genetic innovations above and beyond the contributions of peak cortisol were found for other measures of cortisol reactivity such as AUC. This study is one of the largest twin-based samples to examine the heritability of cortisol reactivity, and results suggest that simpler measures of cortisol reactivity demonstrate higher heritability compared to more complex measurements.

Gaze behavior is associated with the cortisol response to acute psychosocial stress in the virtual TSST

BACKGROUND

The Trier Social Stress Test (TSST) is a reliable tool for psychobiological stress induction. Because of its socio-evaluative nature, it has been useful for investigating gaze behavior. It has been shown that healthy people avoid looking toward faces when under stress, a finding that corroborates studies demonstrating avoidance of eye contact in social anxiety disorder. Yet, little is known about the relationship between gaze behavior and the biological stress response.

METHODS

In a final sample of 74 healthy males, a virtual reality version of the Trier Social Stress Test (TSST-VR) with an integrated eye tracker was implemented to investigate gaze behavior during acute stress induction. Stress response measures were collected via saliva samples and subjective stress ratings. Additional questionnaires were administered for examining the influence of social anxiety traits.

RESULTS

The TSST-VR elicited a significant psychobiological stress response. Overall, higher gaze times on judges compared to surroundings were found in the speech task while this pattern was reversed in the arithmetic task. Critically, there was a significant negative association between gaze time on judges and cortisol output in cortisol responders.

CONCLUSIONS

In a non-clinical sample, avoidance of gaze is associated with a stronger cortisol response to acute stress. This study demonstrates the potential of eye tracking to disentangle the effects of acute stress on social interaction, warranting further investigation in clinical populations characterized by high levels of anxiety in social situations, such as social anxiety and autism spectrum disorder.

Rebuilding Microbiome for Mitigating Traumatic Brain Injury: Importance of Restructuring the Gut-Microbiome-Brain Axis

Traumatic brain injury (TBI) is a damage to the brain from an external force that results in temporary or permanent impairment in brain functions. Unfortunately, not many treatment options are available to TBI patients. Therefore, knowledge of the complex interplay between gut microbiome (GM) and brain health may shed novel insights as it is a rapidly expanding field of research around the world. Recent studies show that GM plays important roles in shaping neurogenerative processes such as blood-brain-barrier (BBB), myelination, neurogenesis, and microglial maturation. In addition, GM is also known to modulate many aspects of neurological behavior and cognition; however, not much is known about the role of GM in brain injuries. Since GM has been shown to improve cellular and molecular functions via mitigating TBI-induced pathologies such as BBB permeability, neuroinflammation, astroglia activation, and mitochondrial dysfunction, herein we discuss how a dysbiotic gut environment, which in fact, contributes to central nervous system (CNS) disorders during brain injury and how to potentially ward off these harmful effects. We further opine that a better understanding of GM-brain (GMB) axis could help assist in designing better treatment and management strategies in future for the patients who are faced with limited options.

DNA damage, salivary cortisol levels, and cognitive parameters in a nursing team

In a cross-sectional study of women in a nursing team at a university hospital in southern Brazil, we studied DNA damage, salivary cortisol levels, and cognition. DNA damage was measured in blood leukocytes with the comet assay and the micronucleus test. Salivary cortisol levels were determined upon waking, 30 min later, and at bedtime. Cognition was evaluated according to the Stroop, Digit span and Word span tests. Cortisol levels on waking up were associated negatively with the number of years the employee worked at the institution and positively with the DNA damage in comet assay. Cognitive scores were lower when the cortisol levels were low at awakening and high at bedtime; and were associated positively with educational level. Cortisol status may influence overall health as well as essential work skills, such as attention.

Validity of the Trier Social Stress Test in studying discrimination stress

To test the validity of a modified Trier Social Stress Test (TSST) for studying stress reactivity in sexual minority women. Two hundred seventy-four female participants (66.4% Black American), half of whom identified as lesbian/gay or bisexual and half as heterosexual, completed the TSST with instructions to describe an experience of discrimination. Cortisol levels and negative emotion scores increased, and heart rate variability decreased in response to the TSST, and the magnitude of these responses varied as a function of sexual orientation and race. Women who discussed sexual orientation as a source of discrimination had greater increases in cortisol and negative mood following the TSST. The modified instructions did not compromise the validity of the TSST. Prompting participants to discuss specific sources of discrimination may be a useful adaptation of the TSST in studying minority stress reactivity. SUMMARY The goal of the present study was to adapt a widely used measure of stress reactivity to study the impact of experiences with discrimination on biological systems involved in regulating the stress response. The modification included asking women to discuss a time when they had been treated unfairly and to describe how they responded to that experience. The magnitude of response to the task varied as a function of sexual orientation and race, and the topics discussed, demonstrating usefulness of the modification for studying the impact of discrimination stress of physical health.