Temperament and response to the Trier Social Stress Test

Introversion and the frequency and intensity of daily uplifts and hassles

OBJECTIVE

There is reason to believe that introversion may relate to different patterns of negative and positive experiences in everyday life ("hassles" and "uplifts"), but there is little evidence for this based on reports made in daily life as events occur. We thus extend the literature by using data from ecological momentary assessments to examine whether introversion is associated with either the frequency or intensity of hassles and uplifts.

METHOD

Participants (N = 242) were community-dwelling adults (63% Black, 24% Hispanic; ages 25-65; 65% women) who completed baseline measures of personality and mental health, followed by reports of hassles and uplifts 5x/day for 14 days. We present associations between introversion and hassles/uplifts both with and without controlling for mood-related factors (neuroticism, recent symptoms of depression, and anxiety).

RESULTS

Introversion was associated with reporting less frequent and less enjoyable uplifts, but not with overall hassle frequency or unpleasantness; exploratory analyses suggest associations with specific types of hassles.

CONCLUSIONS

Our results expand understanding of the role of introversion in everyday experiences, suggesting an overall association between introversion and uplifts (but not hassles, broadly) in daily life. Better understanding of such connections may inform future research to determine mechanisms by which introversion relates to health.

Associations between Autonomic and Endocrine Reactivity to Stress in Adolescence: Related to the Development of Anxiety?

Internalizing disorders in adolescence have been associated with disturbances in autonomic and endocrine functioning. Because the prefrontal cortex and the limbic system play a central role in regulating both the autonomic and the endocrine systems, their joint functioning is hypothesized to provide information about the potential development of internalizing symptoms throughout adolescence, notably in the preclinical stage. This hypothesis was tested in a sample of 198 adolescents from the general population. Heart rate variability (HRV) and skin conductance levels (SCLs) were measured before, during, and after a public speaking task. These autonomic parameters were associated with cortisol response to the task in the complete sample as well as in low- and high-anxiety adolescents separately. Self-reported social anxiety, low HRV, and high SCL recovery values were predictive of cortisol response. Importantly, in low-anxiety adolescents, only HRV during the task predicted the cortisol response, whereas, in their highly anxious peers, both HRV and SCL were strongly associated with this response. In the latter finding, age was a prominent factor. Additional analyses supported the idea that the interaction of autonomic and endocrine reactivity is subject to natural development. These findings provide evidence that adolescence might be a period of highly interactive emotional–neurobiological development, particularly with respect to the development of stress management skills.

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.

Associations between Sleep Quality and Heart Rate Variability: Implications for a Biological Model of Stress Detection Using Wearable Technology

INTRODUCTION

The autonomic nervous system plays a vital role in the modulation of many vital bodily functions, one of which is sleep and wakefulness. Many studies have investigated the link between autonomic dysfunction and sleep cycles; however, few studies have investigated the links between short-term sleep health, as determined by the Pittsburgh Quality of Sleep Index (PSQI), such as subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction, and autonomic functioning in healthy individuals.

AIM

In this cross-sectional study, the aim was to investigate the links between short-term sleep quality and duration, and heart rate variability in 60 healthy individuals, in order to provide useful information about the effects of stress and sleep on heart rate variability (HRV) indices, which in turn could be integrated into biological models for wearable devices.

METHODS

Sleep parameters were collected from participants on commencement of the study, and HRV was derived using an electrocardiogram (ECG) during a resting and stress task (Trier Stress Test).

RESULT

Low-frequency to high-frequency (LF:HF) ratio was significantly higher during the stress task than during the baseline resting phase, and very-low-frequency and high-frequency HRV were inversely related to impaired sleep during stress tasks.

CONCLUSION

Given the ubiquitous nature of wearable technologies for monitoring health states, in particular HRV, it is important to consider the impacts of sleep states when using these technologies to interpret data. Very-low-frequency HRV during the stress task was found to be inversely related to three negative sleep indices: sleep quality, daytime dysfunction, and global sleep score.

Stress Watch: The Use of Heart Rate and Heart Rate Variability to Detect Stress: A Pilot Study Using Smart Watch Wearables

Stress is an inherent part of the normal human experience. Although, for the most part, this stress response is advantageous, chronic, heightened, or inappropriate stress responses can have deleterious effects on the human body. It has been suggested that individuals who experience repeated or prolonged stress exhibit blunted biological stress responses when compared to the general population. Thus, when assessing whether a ubiquitous stress response exists, it is important to stratify based on resting levels in the absence of stress. Research has shown that stress that causes symptomatic responses requires early intervention in order to mitigate possible associated mental health decline and personal risks. Given this, real-time monitoring of stress may provide immediate biofeedback to the individual and allow for early self-intervention. This study aimed to determine if the change in heart rate variability could predict, in two different cohorts, the quality of response to acute stress when exposed to an acute stressor and, in turn, contribute to the development of a physiological algorithm for stress which could be utilized in future smartwatch technologies. This study also aimed to assess whether baseline stress levels may affect the changes seen in heart rate variability at baseline and following stress tasks. A total of 30 student doctor participants and 30 participants from the general population were recruited for the study. The Trier Stress Test was utilized to induce stress, with resting and stress phase ECGs recorded, as well as inter-second heart rate (recorded using a FitBit). Although the present study failed to identify ubiquitous patterns of HRV and HR changes during stress, it did identify novel changes in these parameters between resting and stress states. This study has shown that the utilization of HRV as a measure of stress should be calculated with consideration of resting (baseline) anxiety and stress states in order to ensure an accurate measure of the effects of additive acute stress.

Emotionality vs. Other Biobehavioural Traits: A Look at Neurochemical Biomarkers for Their Differentiation

This review highlights the differential contributions of multiple neurochemical systems to temperament traits related and those that are unrelated to emotionality, even though these systems have a significant overlap. The difference in neurochemical biomarkers of these traits is analysed from the perspective of the neurochemical model, Functional Ensemble of Temperament (FET) that uses multi-marker and constructivism principles. Special attention is given to a differential contribution of hypothalamic-pituitary hormones and opioid neuropeptides implicated in both emotional and non-emotional regulation. The review highlights the role of the mu-opioid receptor system in dispositional emotional valence and the role of the kappa-opioid system in dispositional perceptual and behavioural alertness. These opioid receptor (OR) systems, microbiota and cytokines are produced in three neuroanatomically distinct complexes in the brain and the body, which all together integrate dispositional emotionality. In contrast, hormones could be seen as neurochemical biomarkers of non-emotional aspects of behavioural regulation related to the construction of behaviour in fast-changing and current situations. As examples of the role of hormones, the review summarised their contribution to temperament traits of Sensation Seeking (SS) and Empathy (EMP), which FET considers as non-emotionality traits related to behavioural orientation. SS is presented here as based on (higher) testosterone (fluctuating), adrenaline and (low) cortisol systems, and EMP, as based on (higher) oxytocin, reciprocally coupled with vasopressin and (lower) testosterone. Due to the involvement of gonadal hormones, there are sex and age differences in these traits that could be explained by evolutionary theory. There are, therefore, specific neurochemical biomarkers differentiating (OR-based) dispositional emotionality and (hormones-based) body's regulation in fast-changing events. Here we propose to consider dispositional emotionality associated with OR systems as emotionality in a true sense, whereas to consider hormonal ensembles regulating SS and EMP as systems of behavioural orientation and not emotionality.

Comparison of hypothalamo-pituitary-adrenal function in treatment resistant unipolar and bipolar depression

Altered functioning of the hypothalamic-pituitary-adrenal (HPA) axis has been demonstrated in patients with treatment-resistant depression, although studies have often conflated patients with unipolar and bipolar depression. This is problematic given that the two groups often present with opposed neurovegetative symptom patterns. The aim of this study was to test, for the first time, whether post-awakening cortisol, a highly reliable, naturalistic measure of HPA functioning, could distinguish patients with clearly defined treatment-resistant unipolar (TRUD) and bipolar depression (TRBD). A total of 37 patients with TRUD, 17 patients with TRBD, and 47 healthy controls were recruited. Areas under the curve (AUC) with respect to the ground (g) and increase (i) of post-awakening cortisol concentrations (awakening, +15, +30, +45, +60, +90 min) were measured over two days. Patients with TRUD had higher total cortisol production in the morning hours compared to controls (AUCg, p = 0.01), while they did not differ in terms of the awakening response (AUCi, p = 0.28). By contrast, subjects with TRBD had lower total cortisol when compared to controls by trend (AUCg, p = 0.07), while they did not differ in the awakening response (AUCi, p = 0.15). A direct comparison of TRUD and TRBD revealed differences in the AUCg (p = 0.003) and AUCi (p = 0.03). This finding of comparatively elevated HPA axis activity in the morning in TRUD and attenuated HPA axis activity in TRBD attests to a fundamental biological distinction between unipolar and bipolar depression. It has implications for the understanding and treatment of bipolar depression and in differentiating the two types of depression.

Parsing inter- and intra-individual variability in key nervous system mechanisms of stress responsivity and across functional domains

Exposure to stressful events is omnipresent in modern human life, yet people show considerable heterogeneity in the impact of stress exposure(s) on their functionality and overall health. Encounter with stressor(s) is counteracted by an intricate repertoire of nervous-system responses. This narrative review starts with a brief summary of the vast evidence that supports heart rate variability, cortisol secretion, and large-scale cortical network interactions as kay physiological, endocrinological, and neural mechanisms of stress responsivity, respectively. The second section highlights potential sources for inter-individual variability in these mechanisms, by focusing on biological, environmental, social, habitual, and psychological factors that may influence stress responsivity patterns and thus contribute to heterogeneity in the impact of stress exposure on functionality and health. The third section introduces intra-individually variability in stress responsivity across functional domains as a novel putative source for heterogeneity in the impact of stress exposure. Challenges and future directions are further discussed. Parsing inter- and intra-individual variability in nervous-system mechanisms of stress responsivity and across functional domains is critical towards potential clinical translation.

Physiological stressor impact on peripheral facial temperature, Il-6 and mean arterial pressure, in young people

Nowadays, stress is part of everyday life, whose long-term effects can trigger health risks. Among the main alterations that occur in the human body we can find the variation of inflammatory activity, blood pressure, and facial peripheral temperature. The objective of this work is to show the facial thermal behavior for men and women, as well as the differences in vascular and inflammatory responses induced by the effect of acute social stress. The Trier Social Stress Test was applied to 15 women and 15 men, free of disease, with an average age of 23.8 years and a standard deviation of 5.52. After capturing the baseline state, and at the end of the test, the inflammatory activity was measured through salivary interleukin-6; the mean blood pressure, and the capture of facial thermographic images. For the thermal images, six regions of interest (biothermomarkers) were analyzed: forehead, right cheek, left cheek, chin, nose, and corrugator muscle. The results obtained after analyzing the information were: an increase in inflammatory activity, an increase in mean blood pressure, and significant temperature changes in different areas of interest of the face, depending on gender. For men, it only appeared in the region of the nose and women's forehead, cheeks, and nose. Furthermore, the correlation between the three variables (il-6, blood pressure, and temperature) was performed and no significant values were found. Regarding the relationship between genders, only significant values were found for il-6.

Resilience characteristics and prior life stress determine anticipatory response to acute social stress in children aged 7-11 years

OBJECTIVES

To assess the interplay of prior life stress and characteristics of resilience in determining how children cope with potentially stressful situations, using a two-phase study that triangulates parent-child dyadic interview data with subsequent experience of an acute laboratory stressor in 7-11-year-olds.

METHODS

Participants (n = 34) were designated as being in one of four groups based on high/low levels of prior stress experience and high/low resilience ratings assessed during at-home interviews and from questionnaires measuring recent life events, hassles, and trait coping. During a subsequent laboratory stress protocol, salivary cortisol and heart rate were monitored, and a verbal subjective report was provided.

RESULTS

Salivary cortisol showed a significant increase in anticipation of the stress test, heart rate increased during the test, and children self-reported the task as stressful. Males displayed higher levels of cortisol than females in the anticipatory period. We observed no increase in salivary cortisol in response to the stress testing phase. Using the stress/resilience categorization, children with a higher level of resilience were differentiated by cortisol level in anticipation of the acute stress experiment based on their level of prior life stress. Highly resilient children with greater experience of prior life stress showed a lower anticipatory cortisol response than highly resilient children with less experience of prior life stress.

CONCLUSIONS

This study highlights the relevance of contextual factors, such as prior stress experience and resilience, in physiological response to the anticipation of acute stress and has implications for understanding how children cope with stressful experiences. Statement of contribution What is already known on this subject? An adaptation to the stress testing paradigm, the Bath Experimental Stress Test for Children (BEST-C) was found to reliably induce a salivary cortisol response in young children, suggesting that peer matching the audience was an effective modification to laboratory social stress testing. Recent work focusing on early life adversity has seen the emergence of prior stress experience and resilience as key factors in the examination of acute stress responses. However, much of the research regarding the impact of childhood stress is ambiguous; some research suggests that if children have experienced prior stressful life events this will enact a positive effect on stress responses and lead to resilience, and other research suggested that it will have a compounding negative effect. What does the study add? Findings provide support for the capacity of the BEST-C to induce an anticipation stress response in children. Contextual factors e.g., prior stress experience and resilience are key for understanding stress responses. Resilient children with more experience of stress show lower cortisol than those with less stress experience.

Stress reactivity and personality in extreme sport athletes: The psychobiology of BASE jumpers

This is the first report of the psychobiology of stress in BASE jumpers, one of the most dangerous forms of extreme sport. We tested the hypotheses that indicators of emotional style (temperament) predict salivary cortisol reactivity, whereas indicators of intentional goal-setting (persistence and character) predict salivary alpha-amylase reactivity during BASE jumping. Ninety-eight subjects completed the Temperament and Character Inventory (TCI) the day before the jump, and 77 also gave salivary samples at baseline, pre-jump on the bridge over the New River Gorge, and post-jump upon landing. Overall BASE jumpers are highly resilient individuals who are highly self-directed, persistent, and risk-taking, but they are heterogeneous in their motives and stress reactivity in the Hypothalamic-Pituitary-Adrenal (HPA) stress system (cortisol reactivity) and the sympathetic arousal system (alpha-amylase reactivity). Three classes of jumpers were identified using latent class analysis based on their personality profiles, prior jumping experience, and levels of cortisol and alpha-amylase at all three time points. "Masterful" jumpers (class 1) had a strong sense of self-directedness and mastery, extensive prior experience, and had little alpha-amylase reactivity and average cortisol reactivity. "Trustful" jumpers (class 2) were highly cooperative and trustful individuals who had little cortisol reactivity coincident with the social support they experienced prior to jumping. "Courageous" jumpers (class 3) were determined despite anxiety and inexperience, and they had high sympathetic reactivity but average cortisol activation. We conclude that trusting social attachment (Reward Dependence) and not jumping experience predicted low cortisol reactivity, whereas persistence (determination) and not jumping experience predicted high alpha-amylase reactivity.

Effects of Neurexan ® in an experimental acute stress setting--An explorative double-blind study in healthy volunteers

AIMS

The objective of this study was to assess the efficacy profile of Nx4 (Neurexan ®) in an acute experimental stress setting. An acute stress reaction is a biopsychological condition arising in response to an event that is individually regarded as emotionally stressful. Medications can mitigate stress perception and stress reactions, but may also have side effects.

MATERIALS AND METHODS

Sixty-four healthy male and female volunteers participated in this prospective two-arm two-site study following an explorative randomized placebo-controlled double-blind study design. Participants took six tablets of either Nx4 or placebo during a time period of 2.5h before exposure to an acute psychological stressor (Trier Social Stress Test), and were subsequently monitored for 1.5h. Subjective stress ratings as well as cardiovascular and neuroendocrine parameters were analyzed before and after stress exposure.

KEY FINDINGS

All changes in primary and secondary efficacy parameters corresponded well with the experimental acute stress setting. Nx4 did not affect subjective stress ratings but significantly diminished stress-induced increases in salivary cortisol and plasma adrenaline. Nx4 was as safe as placebo and very well tolerated.

SIGNIFICANCE

The results suggest an attenuated neuroendocrine stress response in healthy volunteers induced by Nx4. However, further investigations are needed to confirm these observations as well as to better understand why some parameters were affected while others were not. Future investigations should be extended to chronically stressed individuals with a greater disposition to experience stress in everyday life. ClinicalTrials.gov Identifier: NCT01703819.

Long-Term Outcomes of Very Preterm Birth

Very preterm birth has become more frequent during the past decades due to progress in reproductive medicine, more frequent indicated preterm births due to maternal illnesses, and increasing maternal age. Moreover, survival rates of very preterm children have increased due to improved neonatal management. However, very preterm-born children, adolescents, and young adults are at increased risk for poor cognitive function and socio-emotional problems, which is of growing public health concern. Very premature birth has been studied to unravel consequences of a nonoptimal environment during a developmental period which under normal circumstances would be the last trimester of fetal development. For very preterm children, this developmental period partly occurs outside the womb, which leads to major distress for the immature newborn. For the cerebral cortex, the last trimester of pregnancy is a particularly sensitive period during which cortical folding takes place and the volume increases 4fold. During this period, even minor insults may cascade into disturbances of brain development. The most frequent complication after very preterm birth is related to insufficient functioning of the lungs, which may lead to hypoxic-ischemic incidences and damage to nervous tissue. This review presents evidence for long-term sequels of very premature birth regarding neurocognitive, academic, socio-emotional, and mental health development. Then it discusses possible underlying mechanisms including alterations in brain development, programming of the hypothalamic-pituitary-adrenal axis and circadian rhythmicity, as well as affected parent-child interaction patterns in families with very preterm children. Finally, intervention approaches to improve outcomes after very preterm birth are discussed and directions for future research presented.

The functional significance of shyness in anorexia nervosa

The defining features of anorexia nervosa (AN) include disordered eating and disturbance in the experience of their bodies; however, many women with AN also demonstrate higher harm avoidance (HA), lower novelty seeking, and challenges with interpersonal functioning. The current study explored whether HA and novelty seeking could explain variation in disordered eating and social functioning in healthy control women ( n = 18), weight-restored women with a history of AN (n = 17), and women currently-ill with AN (AN; n = 17). Our results indicated that clinical participants (AN + weight-restored women) reported poorer social skills than healthy control participants. Moreover, the relationship between eating disorder symptoms and social skill deficits was mediated by HA. Follow-up analyses indicated that only the 'shyness with strangers' factor of HA independently mediated this relationship. Collectively, our results suggest a better understanding of shyness in many individuals with eating disorders could inform models of interpersonal functioning in AN.

Association between Blood Level of Plasma Oxytocin and Novelty Seeking among Methadone-Maintained Heroin Users

BACKGROUND

Oxytocin interacts with the dopaminergic system, which plays a role in addiction behaviors. The association between oxytocin and addiction was confirmed in animal studies. Novelty seeking is one of the predictors and indicators of drug addiction. The aim of the present study was to probe the association between oxytocin and novelty seeking.

METHODS

The study was conducted in a methadone maintenance therapy clinic of a medical center in Taiwan; 77 patients with heroin dependency were enrolled. Plasma oxytocin was measured using an ELISA kit. Novelty seeking was measured using an established instrument (the novelty seeking subscale of the Tridimensional Personality Questionnaire).

RESULTS

A significant negative association (ρ = -0.27, p = 0.02; r = -0.34, p = 0.003) between the blood level of plasma oxytocin and novelty seeking was found. This association was significant after controlling the effects of perceived social support and the dosage of methadone (r = -0.32, p = 0.006).

CONCLUSION

The negative association between oxytocin and novelty seeking may provide insight into future treatments for addiction. © 2015 S. Karger AG, Basel.

Personality traits modulate emotional and physiological responses to stress

An individual's susceptibility to psychological and physical disorders associated with chronic stress exposure, for example, cardiovascular and infectious disease, may also be predicted by their reactivity to acute stress. One factor associated with both stress resilience and health outcomes is personality. An understanding of how personality influences responses to acute stress may shed light upon individual differences in susceptibility to chronic stress-linked disease. This study examined the relationships between personality and acute responses to stress in 125 healthy adults, using hierarchical linear regression. We assessed personality traits using the Multidimensional Personality Questionnaire (MPQ-BF), and responses to acute stress (cortisol, heart rate, blood pressure, mood) using a standardized laboratory psychosocial stress task, the Trier Social Stress Test. Individuals with high Negative Emotionality exhibited greater emotional distress and lower blood pressure responses to the Trier Social Stress Test. Individuals with high agentic Positive Emotionality exhibited prolonged heart rate responses to stress, whereas those with high communal Positive Emotionality exhibited smaller cortisol and blood pressure responses. Separate personality traits differentially predicted emotional, cardiovascular, and cortisol responses to a psychosocial stressor in healthy volunteers. Future research investigating the association of personality with chronic stress-related disease may provide further clues to the relationship between acute stress reactivity and susceptibility to disease.

No effects of hydrocortisone and dexamethasone on pain sensitivity in healthy individuals

BACKGROUND

There is some evidence that stress-induced cortisol increase leads to a decrease in pain, while lowering cortisol levels enhances pain sensitivity, but no study has yet investigated both pharmacological enhancement and reduction of cortisol levels in the same individuals.

METHODS

Firstly, we tested in 16 healthy individuals whether the treatment with hydrocortisone and dexamethasone, respectively, results in altered pain thresholds. Secondly, we aimed to test whether hormone effects are different across the pain range by using ratings for pain stimuli with varying intensity; and thirdly, we tested whether cortisol levels influence the discrimination ability for painful stimuli.

RESULTS

Despite substantial effects of dexamethasone and hydrocortisone administration on cortisol levels, no effect of these drugs was seen in terms of pain sensitivity (pain threshold, pain rating, pain discrimination ability), although comprehensively examined. However, in the placebo condition, a significant negative correlation between cortisol and pain thresholds was seen. Similarly, there were also strong negative associations between cortisol levels in the placebo condition and pain thresholds after drug treatment (especially after hydrocortisone).

CONCLUSION

These findings suggest that short-term variations of cortisol do not influence pain sensitivity whereas, in general, high levels of cortisol are associated with increased pain sensitivity, at least for weak to moderate stimuli.

Temperament moderates the influence of periadolescent social experience on behavior and adrenocortical activity in adult male rats

Adolescence is a period of significant behavioral and physiological maturation, particularly related to stress responses. Animal studies that have tested the influence of adolescent social experiences on stress-related behavioral and physiological development have led to complex results. We used a rodent model of neophobia to test the hypothesis that the influence of adolescent social experience on adult behavior and adrenocortical function is modulated by pre-adolescent temperament. Exploratory activity was assessed in 53 male Sprague-Dawley rats to classify temperament and then they were housed in one of the three conditions during postnatal days (PND) 28-46: (1) with familiar kin, (2) with novel social partners, or (3) individually with no social partners. Effects on adult adrenocortical function were evaluated from fecal samples collected while rats were individually-housed and exposed to a 1-hour novel social challenge during PND 110-114. Adolescent-housing with novel or no social partners led to reduced adult glucocorticoid production compared to adolescent-housing with familiar littermates. Additionally, highly-exploratory pre-weanling rats that were housed with novel social partners during adolescence exhibited increased exploratory behavior and a more rapid return to basal glucocorticoid production in adulthood compared to those housed with familiar or no social partners during adolescence and compared to low-exploratory rats exposed to novel social partners. In sum, relatively short-term adolescent social experiences can cause transient changes in temperament and potentially longer-term changes in recovery of glucocorticoid production in response to adult social challenges. Furthermore, early temperament may modulate the influence of adolescent experiences on adult behavioral and adrenocortical function.

Determinants of physiological and perceived physiological stress reactivity in children and adolescents

AIMS

Abnormal physiological stress reactivity is increasingly investigated as a vulnerability marker for various physical and psychological health problems. However, studies are inconsistent in taking into account potential covariates that may influence the developing stress system. We systematically tested determinants (individual, developmental, environmental and substance use-related) of physiological and perceived physiological stress reactivity. We also examined the relation between physiological and perceived physiological stress reactivity.

METHOD

In a stratified sample of 363 children (7-12 years) and 344 adolescents (13-20 years) from the general population, we examined cortisol, heart rate, respiratory sinus arrhythmia and perceived physiological stress reactivity to a psychosocial stress procedure.

RESULTS

Using multivariate linear regression models, we found that individual, developmental, environmental and substance use-related factors were related to each of the stress response indices. These determinant factors were different for each of the stress reactivity indices, and different in children versus adolescents. Perceived physiological stress reactivity predicted cortisol reactivity in adolescents only. All other relations between perceived physiological and physiological stress reactivity were not significant.

CONCLUSIONS

As physiological stress variables are often examined as vulnerability markers for the development of health problems, we maintain that it is essential that future studies take into consideration factors that may account for found relations. Our study provides an overview and indication of which variables should be considered in the investigation of the relation between physiological stress indices and illness.

Novelty-seeking and avoidant coping strategies are associated with academic stress in Korean medical students

High levels of stress and depression in medical students is raising concern. In this study, we sought to identify coping strategies and other factors influencing academic stress in medical students. We enrolled 157 students from the University of Ulsan College of Medicine, Korea, in November, 2010. We used the Medical Stress Scale, Temperament and Character Inventory, Hamilton Depression Scale, Beck Depression Inventory, and Coping Response Inventory to assess psychological parameters. We used Pearson's correlation and linear regression analyses to analyze the data. Novelty-seeking, self-directedness, cooperativeness, coping strategy, and depression scale scores all correlated significantly with stress level. Linear regression analysis indicated that students who are novelty-seeking, likely to use avoidant coping strategies, and unlikely to use active-cognitive and active-behavioral strategies tend to have higher stress levels. Reduction of stress in medical students may be achieved through evaluation of coping strategies and personality features and use of interventions to promote active coping strategies.

Acute psychosocial stress: does the emotional stress response correspond with physiological responses?

Most stress experiences are accompanied by physiological and psychological responses. Laboratory stressors such as the Trier Social Stress Test (TSST) induce reliable stress responses, which are mainly assessed for biological parameters such as cortisol. The associations between physiological and psychological responses to the TSST have been rarely investigated and are addressed in this review. Up to August 2011, 358 studies were published in PubMed examining the impact of the TSST (71%) or variations of the protocol. A total of 49 studies were considered based on the following three inclusion criteria: (1) exposure to the standard TSST or slightly modified TSST versions, (2) at least one assessment of subjective emotional stress experience before, during or after the TSST, (3) reported associations between acute physiological and emotional stress measures. Significant correlations between cortisol responses and perceived emotional stress variables were found in approximately 25% of the studies. Our descriptive analysis revealed various essential elements that potentially contribute to this apparent dissociation, reaching from differing assessment approaches and methodological features of the stress protocols to possible mediating factors and interindividual differences in the degree of psychophysiological correspondence.

Altered response to neuroendocrine challenge linked to indices of the metabolic syndrome in healthy adults

Metabolic syndrome (MetS) is characterized by central obesity, hypertension, insulin resistance, and hypercholesterolemia. Hypothalamic-pituitary-adrenal (HPA) axis activity is frequently abnormal in MetS, and excessive cortisol exposure may be implicated in metabolic derangements. We investigated the hypothesis that cortisol and adrenocorticotropic hormone (ACTH) responses to a standardized neuroendocrine challenge test would be associated with indices of MetS in a community sample of healthy adults. Healthy adults, 125 men and 170 women, without significant medical problems or chronic medications were recruited from the community. Participants completed the dexamethasone/corticotropin-releasing hormone (Dex/CRH) test, and anthropometric measurements, blood pressure, glycosylated hemoglobin (HbA1c), and cholesterol were measured. Participants reported on their history of early life stress and recent stress, as well as mood and anxiety symptoms. Cortisol and ACTH responses to the Dex/CRH test were negatively associated with measures of central adiposity (p<0.001) and blood pressure (p<0.01), and positively associated with HDL cholesterol (p<0.01). These findings remained significant after controlling for body mass index (BMI). Measures of stress and anxiety and depressive symptoms were negatively correlated with cortisol and ACTH responses in the Dex/CRH test but were not related to MetS indices. That altered HPA axis function is linked to MetS components even in a healthy community sample suggests that these processes may be involved in the pathogenesis of MetS. Identification of premorbid risk processes might allow for detection and intervention prior to the development of disease.

Neurobiological and psychopathological variables related to emotional instability: a study of their capability to discriminate patients with bulimia nervosa from healthy controls

OBJECTIVE

To analyze the capability of a set of neurobiological and psychopathological variables to discriminate bulimia nervosa (BN) patients from healthy controls.

METHOD

Seventy-five female patients with purging BN and 30 healthy controls were compared for psychopathology (impulsivity, borderline personality traits, depressive symptoms and self-defeating personality traits) and neurobiological parameters reflecting hypothalamic-pituitary-adrenal axis activity (morning serum cortisol before and after dexamethasone) and monoamine activity (24-hour urinary excretion of norepinephrine, serotonin, dopamine, and their main metabolites: 3-methoxy-4-hydroxyphenylglycol, 5-hydroxyindoleacetic acid, and homovanillic acid). Furthermore, the relationships between the 2 sets of variables were compared in the 2 samples.

RESULTS

BN patients displayed higher impulsivity, more severe depressive features, and more borderline and self-defeating personality traits than controls. The 4 psychopathological variables were strongly interrelated in patients, whereas only depressive features correlated with self-defeating personality traits in controls. Patients had lower 24-hour excretion of serotonin and dopamine than controls, as well as lower ability to suppress cortisol. The relations between the biochemical and the psychopathological variables were only significant in the BN patients, but not in the control group. When discriminant analysis methods were applied, patients and controls differed for psychopathology (impulsive behaviors and borderline personality traits) and biological parameters (baseline cortisol and dopamine excretion), but when the variables were analyzed together, the differences in neurobiological parameters appeared as mediated by the psychopathological status.

DISCUSSION

Our results suggest that hypothalamic-pituitary-adrenal axis activity, dopamine activity and other biological parameters are worthy of further study as potential dimensional markers of BN, although they seem to depend on the psychopathological status of the patients, in such a way that the psychopathological items associated with emotional instability (impulsivity and borderline personality traits) seem to be more reliable as clinical markers at the time being.

A novelty seeking phenotype is related to chronic hypothalamic-pituitary-adrenal activity reflected by hair cortisol

Reduced hypothalamic pituitary adrenal (HPA) activity is associated with greater novelty seeking in humans. Hair cortisol represents an integrated proxy measure of total cortisol production/release over an extended period of time and may be a valuable tool for tracking the HPA system. Sampling approaches (collection of blood, saliva, urine, or feces) for socially housed nonhuman primates present a number of technical challenges for collection particularly when repeated sampling is necessary. Herein we describe a relationship between cortisol levels measured in hair collected from 230 socially housed female vervet (Chlorocebus aethiops sabaeus) monkeys and a free-choice novelty seeking phenotype. A predator-like object was placed at the periphery of the outdoor enclosures for 30 min and speed of approach (latency to approach within 1m) and persistence of interest (number of 1 min intervals within 1m) were scored. A composite Novelty Seeking score, combining these two measures, was calculated. The intra-class correlation coefficient (ICC=.68) for two different objects across years indicated that this score reflects a stable aspect of temperament. Hair samples were collected from each subject approximately 3-6 months following the second assessment; cortisol levels were determined from the hair. A significant inverse relationship of Novelty Seeking score with hair cortisol level (p<.01) was noted. The high hair cortisol groups had significantly lower Novelty Seeking scores than the low cortisol groups both years (p's<.05). These results suggest that low average cortisol levels promote novelty seeking, while high average levels inhibit novelty seeking behavior.

Sensory Processing, Physiological Stress, and Sleep Behaviors in Children with and without Autism Spectrum Disorders

Sleep problems have been frequently identified in children with autism spectrum disorders (ASD). It has been proposed that some sleep problems are due to sensory sensitivity. The purpose of this study was to examine the relationship between physiologic responses to sensation and sleep in children with and without ASD. Fifty-five children participated in the study (ASD, n = 27; typical, n = 28). All children participated in a sensory challenge laboratory protocol. Electrodermal reactivity and salivary cortisol were used as physiological indicators of sensory responsivity. Behavioral data were collected using the Sensory Profile and the Child Behavior Checklist. Results confirmed that children with ASD have a higher prevalence of atypical sensory behaviors and sleep disturbances than typical children. Behavioral and physiological measures were able to predict good sleepers versus poor sleepers with 85.7% accuracy, suggesting that atypical sensory behaviors are important to consider in relation to sleep deficits in children.

Baseline 'state anxiety' influences HPA-axis sensitivity to one sham-controlled HF-rTMS session applied to the right dorsolateral prefrontal cortex

Although negative results have been reported, an important aspect of the physiology of repetitive transcranial magnetic stimulation (rTMS) could be related to the endocrinological response of the hypothalamic-pituitary-adrenal (HPA) axis, such as cortisol secretion. Because endocrinological responses are influenced by anxiety states, this could influence the effect of rTMS in healthy individuals. In this sham-controlled, "single blind" crossover study, we examined whether one session of HF-rTMS could affect the HPA-system, when taking into account individual state anxiety scores based on the State-Trait Anxiety Inventory (STAI). Twenty-four healthy rTMS naïve females received one sham-controlled high frequency (HF)-rTMS session delivered on the right dorsolateral prefrontal cortex (DLPFC). The Profile of Mood States (POMS) questionnaire, together with salivary cortisol samples, was collected before, just after and 30 min post HF-rTMS. To examine whether state anxiety could influence endocrinological outcome measurements, we administered the STAI-state just before each HF-rTMS experiment started. Based on the POMS questionnaire, no mood changes were observed. Without taking individual state anxiety scores into account, one sham-controlled right-sided HF-rTMS session did not influence the HPA-system. When taking into account individual STAI-state scores, we found that healthy women scoring higher on the STAI-state displayed a significantly more sensitive HPA-system, resulting in salivary cortisol concentration increases after real HF-rTMS, compared to those scoring lower on this anxiety scale. Our results indicate that healthy women scoring high on state anxiety display a more sensitive HPA-system when receiving one right-sided HF-rTMS session. Our findings suggest that the incorporation of individual anxiety states in experimental rTMS research could add further information about its neurobiological influences on the HPA-system.

[Childhood maltreatment and adult psychopathology: pathways to hypothalamic-pituitary-adrenal axis dysfunction]

OBJECTIVE

The aim of this paper was to examine the relationship between childhood maltreatment and adult psychopathology, as reflected in hypothalamic-pituitary-adrenal axis dysfunction.

METHOD

A selective review of the relevant literature was undertaken in order to identify key and illustrative research findings.

RESULTS

There is now a substantial body of preclinical and clinical evidence derived from a variety of experimental paradigms showing how early-life stress is related to hypothalamic-pituitary-adrenal axis function and psychological state in adulthood, and how that relationship can be modulated by other factors.

DISCUSSION

The risk for adult psychopathology and hypothalamic-pituitary-adrenal axis dysfunction is related to a complex interaction among multiple experiential factors, as well as to susceptibility genes that interact with those factors. Although acute hypothalamic-pituitary-adrenal axis responses to stress are generally adaptive, excessive responses can lead to deleterious effects. Early-life stress alters hypothalamic-pituitary-adrenal axis function and behavior, but the pattern of hypothalamic-pituitary-adrenal dysfunction and psychological outcome in adulthood reflect both the characteristics of the stressor and other modifying factors.

CONCLUSION

Research to date has identified multiple determinants of the hypothalamic-pituitary-adrenal axis dysfunction seen in adults with a history of childhood maltreatment or other early-life stress. Further work is needed to establish whether hypothalamic-pituitary-adrenal axis abnormalities in this context can be used to develop risk endophenotypes for psychiatric and physical illnesses.

The other side of the curve: examining the relationship between pre-stressor physiological responses and stress reactivity

There is widespread consensus that stress induces dramatic physiological changes, but no agreement on the quantitative parameters that are appropriate to measure these responses. More importantly, the interpretation of various stress measurements, and how individual responses should be evaluated, has not been properly addressed. Even the definition of baseline, against which stress responses must be measured, is not clearly established. The current experiment sought to address these shortcomings by comparing the predictive value of different calculated parameters for psychosocial and physiological measures of stress across individuals. Subjects were 29 male and 59 female healthy undergraduate students with saliva samples collected over a 3-h interval that included a Trier Social Stress Test. Salivary cortisol and alpha-amylase response were analyzed using the absolute concentration, the percent change in concentration, the area under the curve (Pruessner et al., 2003), and the arrival index (change from arrival to 1h after arrival). The arrival index correlated with the subsequent stress response for both cortisol (r=0.76, p<0.01) and alpha-amylase (r=0.86, p<0.01). The arrival index for both cortisol and alpha-amylase was also related to subjective ratings of anxiety following the psychosocial stressor. A subset of individuals with high self-reported anxiety also displayed higher reactivity in response to the psychosocial stressor. Thus, the magnitude of the difference in cortisol and alpha-amylase between arrival and 1h after arrival was a predictor of subsequent stress reactivity. These findings suggest that different psychosocial profiles may be reflected in cortisol and alpha-amylase changes. For this reason: (1) a recovery period after arrival is essential to establish a baseline, (2) the difference between arrival and post-recovery period baseline should be included in experimental designs as a predictive variable, and (3) transformation of individual measures into proportional changes relative to the arrival sample is very likely to obscure important underlying individual differences.

Relationships between psychological distress, coping styles, and HPA axis reactivity in healthy adults

Psychological distress and coping styles have been suggested to relate to altered function in the hypothalamic-pituitary-adrenal (HPA) axis, although there remains much to be understood about their relationships. High and low cortisol levels (or reactivity) both represent HPA axis dysfunction, with accumulated evidence suggesting that they are linked to different types of psychopathology. The dexamethasone (DEX)/corticotropin-releasing hormone (CRH) test has been extensively used to identify HPA axis abnormalities in various psychiatric conditions including mood disorders; however, the possible associations of psychological distress and coping styles with HPA axis function have not been well documented using this test. Here, we examined the relationships of HPA axis reactivity as measured by the DEX/CRH test with subjectively perceived psychological distress and coping styles, both of which were assessed with self-report questionnaires, in 121 healthy volunteers. Subjects were divided into three groups by the cortisol suppression pattern, namely the incomplete-suppressors (DST-Cortisol ≥ 5 μg/dL or DEX/CRH-Cortisol ≥ 5 μg/dL), moderate-suppressors (DST-Cortisol < 5 μg/dL and 1 μg/dL ≤ DEX/CRH -Cortisol < 5 μg/dL), and enhanced-suppressors (DST-Cortisol < 5 μg/dL and DEX/CRH-Cortisol < 1 μg/dL). The enhanced-suppressors showed significantly higher scores in obsessive-compulsive, interpersonal sensitivity and anxiety symptoms and significantly more frequent use of avoidant coping strategy, compared to the other two groups. These results point to the important role of enhanced suppression of cortisol, or blunted cortisol reactivity, in non-clinical psychopathology such as avoidant coping strategy and greater psychological distress.

Novelty-evoked activity in open field predicts susceptibility to helpless behavior

Learned helplessness in animals has been used to model disorders such as depression and post-traumatic stress disorder (PTSD), but there is a lack of knowledge concerning which individual behavioral characteristics at baseline can predict helpless behavior after exposure to inescapable stress. The first aim of this study was to determine behavioral predictors of helplessness using the novel and familiar open-field tests, sucrose consumption, and passive harm-avoidance tasks before learned helplessness training and testing. Individual differences in physiologic responses to restraint stress were also assessed. A cluster analysis of escape latencies from helplessness testing supported the division of the sample population of Holtzman rats into approximately 50% helpless and 50% non-helpless. Linear regression analyses further revealed that increased reactivity to the novel environment, but not general activity or habituation, predicted susceptibility to learned helplessness. During restraint stress there were no mean differences in heart rate, heart rate variability, and plasma corticosterone between helpless and non-helpless rats; however, a lower heart rate during stress was associated with higher activity levels during exploration. Our most important finding was that by using an innocuous screening tool such as the novel and familiar open-field tests, it was possible to identify subjects that were susceptible to learned helplessness.

Behavioral adjustment in a community sample of boys: links with basal and stress-induced salivary cortisol concentrations

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis has been observed in association with internalizing symptoms and is thought to be involved in the pathogenesis of depression and some anxiety disorders. This study examined basal and stress-induced cortisol concentrations in relation to internalizing and externalizing symptoms in a racially mixed community sample of 102 8-11-year-old boys. Afternoon basal cortisol concentrations were positively correlated with measures of internalizing behavior problems, social problems, and emotionality. Greater change in cortisol across a home-visit challenge task was also significantly associated with internalizing behaviors and social problems, as well as attention and thought problems. The implications of these findings and how they may relate to the pathogenesis of emotional and behavioral problems are discussed.

Higher overcommitment to work is associated with higher plasma cortisol but not ACTH responses in the combined dexamethasone/CRH test in apparently healthy men and women

BACKGROUND

Overcommitment (OC) is a pattern of excessive striving that has been associated with alterations in the hypothalamus-pituitary-adrenal (HPA) system. To investigate whether overcommitment is associated with alterations in HPA system function we measured cortisol and adrenocorticotropin (ACTH) release in response to the combined dexamethasone/CRH test.

METHODS

We recruited 92 men and 108 women of a wide range of OC scores including the minimum (6) and maximum (24) of possible OC scores (mean+/-SEM: 13.25+/-.27). We repeatedly measured plasma cortisol and ACTH levels in the combined dexamethasone/CRH test after injection of 100mul CRH preceded by administration of 1.5mg dexamethasone the night before. Moreover, we assessed depressive symptoms (Beck Depression Inventory, BDI) and work stress (effort-reward-imbalance, ERI).

RESULTS

Independent of age and gender, higher OC was associated with higher repeated cortisol (interaction time-by-OC: p=.014, f=.15) but not ACTH (p=.22) secretion in the combined dexamethasone/CRH test. Similarly, higher cortisol (beta=.16, p=.029, R(2)=.02) but not ACTH (p=.47) increase following CRH injection was predicted by higher OC. Depressive symptoms (BDI score) and work stress scores (effort-reward-ratio) did not relate to neuroendocrine responses to the dexamethasone/CRH test. Controlling for depressive symptoms and work stress scores in addition to age and gender did not change results. OC was not associated with ACTH or cortisol pre-test levels.

DISCUSSION

Whereas OC was not associated with alterations in negative feedback sensitivity after dexamethasone administration, our findings indicate that with increasing OC scores, a higher reactivity of the adrenal cortex together with a normal reactivity of the pituitary is observed following subsequent stimulation by CRH injection.

The moderating role of sensory Overresponsivity in HPA activity: a pilot study with children diagnosed with ADHD

OBJECTIVE

To determine if sensory overresponsivity (SOR) is a moderating condition impacting the activity of the Hypothalamic Pituitary Adrenal (HPA) Axis in children with ADHD.

METHOD

Participants were children with (n = 24) and without ADHD (n = 24). Children in the ADHD group were divided into SOR (ADHDs) and non-SOR (ADHDt) groups using the Sensory Over-Responsivity Inventory. All children participated in the Sensory Challenge Protocol. Salivary cortisol was used as a measure of HPA activity. Two prechallenge and seven postchallenge samples of saliva were taken. Cortisol patterns between groups were examined using a mixed-effects ANOVA.

RESULTS

There was a borderline significant difference found between the ADHDt and ADHDs group (p = .056) and a significant difference between ADHDt and the typical group (p = .014).

CONCLUSION

Preliminary results support the premise that SOR may be a moderating variable used to create subgroups in diagnostic populations such as ADHD. (J. of Att. Dis. 2010; 13(5) 468-478).

Cloninger's temperament traits and preclinical atherosclerosis: the Cardiovascular Risk in Young Finns Study

OBJECTIVE

Cloninger's psychobiological model of temperament has recently raised interest as a risk factor for CHD. However, there are no studies that have examined the associations of Cloninger's temperament traits with atherosclerosis.

METHODS

The subjects were 398 men and 657 women (mean age 31.7 years) participating in the Cardiovascular Risk in Young Finns Study. Linear regression analyses were used to examine the cross-sectional associations between temperament traits and preclinical atherosclerosis. Preclinical atherosclerosis was measured with carotid intima-media thickness ultrasound.

RESULTS

Higher novelty seeking (NS) and reward dependence (RD) and lower harm avoidance (HA) were associated with preclinical atherosclerosis. In NS and RD, associations remained significant after adjustments for various risk factors. The effect sizes of these associations were comparable to those of traditional risk factors of coronary heart disease, which is a major finding. No association for persistence (P) was found.

CONCLUSIONS

The present findings imply that examining a wider range of temperament and personality factors may offer new information that can help in explaining the between-individual variation in atherosclerosis and CHD morbidity.

Childhood parental loss and adult hypothalamic-pituitary-adrenal function

BACKGROUND

Several decades of research link childhood parental loss with risk for major depression and other forms of psychopathology. A large body of preclinical work on maternal separation and some recent studies of humans with childhood parental loss have demonstrated alterations of hypothalamic-pituitary-adrenal (HPA) axis function that could predispose to the development of psychiatric disorders.

METHODS

Eighty-eight healthy adults with no current Axis I psychiatric disorder participated in this study. Forty-four participants experienced parental loss during childhood, including 19 with a history of parental death and 25 with a history of prolonged parental separation. The loss group was compared with a matched group of individuals who reported no history of childhood parental separation or childhood maltreatment. Participants completed diagnostic interviews and questionnaires and the dexamethasone/corticotropin-releasing hormone (Dex/CRH) test. Repeated measures general linear models were used to test the effects of parental loss, parental care, gender, and age on the hormone responses to the Dex/CRH test.

RESULTS

Parental loss was associated with increased cortisol responses to the test, particularly in men. The effect of loss was moderated by levels of parental care; participants with parental desertion and very low levels of care had attenuated cortisol responses. Adrenocorticotropic hormone responses to the Dex/CRH test did not differ significantly as a function of parental loss.

CONCLUSIONS

These findings are consistent with the hypothesis that early parental loss induces enduring changes in neuroendocrine function.

Cortisol and ACTH responses to the Dex/CRH test: influence of temperament

Temperament and personality traits such as neuroticism and behavioral inhibition are prospective predictors of the onset of depression and anxiety disorders. Exposure to stress is also linked to the development of these disorders, and neuroticism and inhibition may confer or reflect sensitivity to stressors. Several lines of research have documented hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis in some patients with major depression, as well as in children and non-human primates with inhibited temperaments. The present investigation tested the hypothesis that stress-reactive temperaments would be predictive of plasma adrenocorticotropin (ACTH) and cortisol concentrations in the dexamethasone/corticotropin-releasing hormone (Dex/CRH) test. Sixty adults completed diagnostic interviews and questionnaires assessing the temperament domains of novelty seeking and harm avoidance and symptoms of anxiety and depression. All subjects were free of any current or past Axis I psychiatric disorder. The Dex/CRH test was performed on a separate visit. A repeated-measures general linear model (GLM) showed a main effect of harm avoidance in predicting cortisol concentrations in the test (F(1, 58)=4.86, p<.05). The GLM for novelty seeking and cortisol response also showed a main effect (F(1, 58)=5.28, p<.05). Higher cortisol concentrations were associated with higher levels of harm avoidance and lower levels of novelty seeking. A significant interaction of time with harm avoidance and novelty seeking (F(4, 53)=3.37, p<.05) revealed that participants with both high levels of harm avoidance and low levels of novelty seeking had the highest cortisol responses to the Dex/CRH test. Plasma ACTH concentrations did not differ as a function of temperament. The results indicate that temperament traits linked to sensitivity to negative stimuli are associated with greater cortisol reactivity during the Dex/CRH test. Increased adrenocortical reactivity, which previously has been linked to major depression and anxiety disorders, may contribute to the association between temperament/personality traits and these disorders.