Personality dimensions harm avoidance and self-directedness predict the cortisol awakening response in military men

To account for individual differences in vulnerability for stress-related disorders, studies have examined the relationship between hypothalamic-pituitary-adrenal (HPA) axis functioning and personality. The present study examined the relationship between the free fraction of cortisol in saliva after awakening and personality as measured with Cloninger's Temperament and Character Inventory [Cloninger, C.R., Przybeck, T.R., Svrakic, D.M., Wetzel, R.D., 1994. The Temperament and Character Inventory (TCI): A Guide to its Development and Use. Washington University, Center for Psychobiology of Personality, St. Louis, MO] in 107 healthy male soldiers. Harm avoidance explained 9% of variance in cortisol levels after awakening (AUCG), and harm avoidance and self-directedness predicted 10% of variance in mean cortisol increase. The cortisol awakening response (CAR) was lower in participants with low scores on harm avoidance, and mean cortisol increase after awakening was higher in soldiers high on self-directedness and harm avoidance. These results show that the CAR is related to personality and that it can be used to examine individual differences in HPA (re)activity.     

Social status constrains the stress response in the squirrel monkey.

The influence of dominance on the pituitary-adrenal and gonadal systems was evaluated in male squirrel monkeys. Basal and stress levels of plasma cortisol and testosterone were determined in eight male pairs across a 5-week period. The data indicated that squirrel monkeys have unusually high levels of steroid hormones in comparison to other species. Dominant males had higher levels of cortisol and testosterone and showed a smaller stress response than did subordinate males.     

Social influences on circulating levels of cortisol and prolactin in male talapoin monkeys

Three captive groups of adult talapoin monkeys (Miopithecus talapoin), each with four males and four or five ovariectomized, estrogen-treated females, were observed. Behavioral interactions were recorded and levels of cortisol and prolactin were measured. In each group, males formed a linear dominance order, determined by the direction of spontaneous aggression; highest male rank was associated with frequent socio-sexual interactions and lowest rank with infrequent socio-sexual behavior. The first study compared males' cortisol and prolactin titers when all males were either housed with estrogen-treated females, or singly caged. The two lowest-ranking males of each group had elevated cortisol levels when group-housed; prolactin levels did not reflect these changes. In the second study, males of one group interacted with females when only the lowest-ranking, or the highest-ranking, female was made attractive (i.e., received estradiol), while the other females were present, but not estradiol-treated. Across these conditions (1) frequencies of some socio-sexual and aggressive behaviors changed, (2) cortisol levels increased in all males, and (3) prolactin levels decreased in three of four males. Dissociation of changes in cortisol and prolactin titers suggests that these hormones may be differentially responsive to social modifications, not simply reflecting a single intervening variable, such as "stress."     

Intercorrelations between serum, salivary, and hair cortisol and child-reported estimates of stress in elementary school girls

To evaluate the impact of stress on children's well-being, it is important to have valid and reliable stress assessment methods. Nevertheless, selection of an appropriate method for a particular research question may not be straightforward, as there is currently no consensus on a reference method to measure stress in children. This article examined to what extent childhood stress can be estimated accurately by stressor questionnaires (i.e., Coddington life events scale) and biological markers (serum, salivary, and hair cortisol) using the Triads (a triangulation) method in 272 elementary school girls. Salivary cortisol was shown to most accurately indicate true childhood stress for short periods in the past (i.e., last 3 months), whereas hair cortisol may be preferred above salivary measurements for periods more distant and thus for chronic stress assessment. However, applicability should be confirmed in larger and more heterogeneous populations.     

The effect of social rank on the physiological response during repeated stressful handling in Zebu cattle (Bos indicus)

Although the order of entry to a handling chute is related to social rank, it is still not clear what the consequences are for Zebu cattle of occupying different ranks when being exposed repeatedly to a stressful handling procedure. Eighteen Brahman cows were observed for 243 h to obtain information on social interactions. From that information, indices of success in displacing other individuals of the herd were calculated to reflect social status of each cow. One week after behavioral observations, the cows were forced 19 times to enter a handling chute where they were palpated and 7 ml of blood was collected from their caudal vein. To have an adrenal activity profile along the experimental period, five blood samples (Days 2, 6, 10, 15, and 19) were chosen for cortisol determination. On each sampling day, the average time in the chute, the order of entry, and a value of entrance consistency were calculated. On average, the high-ranking cows entered the chute before the medium- and low-ranking cows. Medium-ranking cows showed higher consistency when entering the race than high- and low-ranking cows. Low-ranking cows had significantly lower cortisol levels than the other two groups since the second sample (Day 6 in the race), and had higher cortisol levels the first time handled than at subsequent sampling days. It is suggested that low-ranking cows adopt a passive strategy that allows them to have a better control over the stressful event, while high-ranking cows respond with higher cortisol levels perhaps because of the need to become aroused to deal with challenges. It was concluded that the herd (a) habituated to repeat handling in a squeeze chute and (b) low-ranking cows responded with lower cortisol concentration to handling.     

Cardiovascular and cortisol reactions to acute psychological stress and cognitive ability in the Dutch Famine Birth Cohort Study

Given evidence linking blunted cardiovascular and cortisol reactions to acute stress and a range of adverse behavioral outcomes, the present study examined the associations between cardiovascular and cortisol reactivity and cognitive ability measured independently of the stress task exposure. Cognitive ability was assessed using the Alice Heim-4 test of general intelligence and two memory tasks in 724 men and women who were part of the Dutch Famine Birth Cohort Study. Blood pressure and heart rate, as well as cortisol reactivity, were measured to a battery of three standard acute stress tasks. Poorer cognitive ability was associated with lower cardiovascular reactions to stress and lower cortisol area under the curve. Our results are consistent with recent findings implicating low physiological stress reactivity in a range of adverse behavioral and health outcomes.     

Individual differences in the cortisol response to stress in young healthy men: testing the roles of perceived stress reactivity and threat appraisal using multiphase latent growth curve modeling

Individual differences in stress reactivity and cognitive appraisal processes are thought to explain part of the heterogeneity in stress responses. This study investigated how perceived typical stress reactivity and momentary cognitive appraisal affect salivary cortisol responses to a laboratory performance stressor with social evaluation in 66 male non-smokers. Multiphase latent growth curve models showed positive associations of perceived stress reactivity and primary appraisal with cortisol responses. An age-adjusted path analysis suggested that primary appraisal mediated the effect of perceived reactivity to social evaluation on cortisol responses, and that effects of primary appraisal were attenuated at high levels of perceived reactivity. Our results suggest that individuals who report that they typically show strong perceived emotional, cognitive and autonomic responses to social evaluative stress tend to perceive the prospect of having to perform in front of an audience as more threatening, and that this appraisal then leads to stronger cortisol responses.     

The effects of running and meditation on beta-endorphin, corticotropin-releasing hormone and cortisol in plasma, and on mood

The relations between three hormones of the hypothalamic-pituitary-adrenocortical (HPA) axis, beta-endorphin (β-EP), corticotropin-releasing hormone (CRH) and cortisol, and mood change were examined in 11 elite runners and 12 highly trained meditators matched in age, sex, and personality. Despite metabolic differences between running and meditation, we predicted that mood change after these activities would be similar when associated with similar hormonal change. Compared to pre-test and control values, mood was elevated after both activities but not significantly different between the two groups at post-test. There were significant elevations of β-EP and CRH after running and of CRH after meditation, but no significant differences in CRH increases between groups. CRH was correlated with positive mood changes after running and meditation. Cortisol levels were generally high but erratic in both groups. We conclude that positive affect is associated with plasma CRH immunoreactivity which itself is significantly associated with circulating β-EP supporting a role for CRH in the release of β-EP. Increased CRH immunoreactivity following meditation indicates, however, that physical exercise is not an essential requirement for CRH release.     

Salivary cortisol, stress and mood in healthy older adults: the Zenith study

The aims of this study were to investigate the relationship between salivary cortisol, stress and mood and to look at the circadian rhythms of positive (PA) and negative (NA) mood in older adults. The participants were 41 healthy adults aged 55-69 years, recruited in Northern Ireland as part of the European Commission-funded Zenith project. Salivary cortisol samples were obtained twice a day (2.30 p.m. and 10.30 p.m.) for 7 consecutive days in conjunction with momentary measures of positive (PA) and negative mood (NA), using PANAS and a trait measure of perceived stress (Perceived Stress Scale). Salivary cortisol levels were measured using an enzyme-linked immunoassay kit. Higher perceived stress levels were associated with lower afternoon PA (r=-0.46, p=0.003) and higher afternoon (r=0.43, p=0.007) and evening (r=0.45, p=0.004) NA. Lower afternoon PA was correlated with higher evening cortisol concentrations (r=-0.47, p=0.002). Greater afternoon PA variability was associated with higher evening cortisol concentrations (r=0.38, p=0.015). A high intra-class correlation between cortisol and positive mood was found (r=0.67, p=0.009). Previously established rhythms for positive and negative mood were confirmed. Interestingly, there was no association between salivary cortisol levels and perceived stress in these healthy older adults. Further, more extensive research is required to better understand the apparent interplay between these variables and ageing.     

The effects of social stress and cortisol responses on the preconscious selective attention to social threat

The purpose of the present study was to investigate the effects of social stress and stress-induced cortisol on the preconscious selective attention to social threat. Twenty healthy participants were administered a masked emotional Stroop task (comparing color-naming latencies for angry, neutral and happy faces) in conditions of rest and social stress. Stress was induced by means of the Trier social stress test. Based on the stress-induced increase in cortisol levels, participants were allocated post hoc (median-split) to a high and low responders group. In contrast to low responders, high responders showed a negative or avoidant attentional bias to threat (i.e. shorter latencies for angry than neutral faces) in the rest condition. Most importantly, although low responders became avoidant, the high responders became vigilant to the angry faces after stress induction. There were no such effects for happy faces. Our findings are in line with previous studies in both animals and humans, that associate high glucocorticoid stress-responsiveness with diminished avoidance and prolonged freezing reactions during stress.     

Effect of age, food deprivation and stress on gastric erosions in the rat

Two experiments were conducted in which rats were subjected to food deprivation and/or cold-restraint stress. In Experiment 1, 40- and 570-day old rats exhibited a significant degree of glandular gastric erosion due to the stress and to the deprivation. Both of these were attributable to the single condition wherein deprivation and stress were combined. No effect involving age was significant. In Experiment 2, 22-day old weanlings exposed to the same conditions evinced a significant glandular erosion effect of the deprivation, but neither the stress nor the interaction effects were significant. It was concluded that 3 hr of cold restraint in the sated mature rat has a relatively minor effect on the stomach. Forty-eight hours of food deprivation, also ineffective by itself in such animals, renders the stomach vulnerable to the effects of stress. In the weanling, in contrast, deprivation alone can cause glandular erosion but its potentiating effect is lacking. With respect to ruminal lesions, it was hypothesized that time without food rather than initial body weight or nutritional deficit is the critical variable.     

Age effects on cortisol levels in depressed patients with and without comorbid post-traumatic stress disorder, and healthy volunteers

BACKGROUND: Post-traumatic stress disorder (PTSD) and major depression are frequently comorbid. Age and major depression are associated with higher cortisol levels and dexamethasone resistance, whereas PTSD is associated with lower cortisol and dexamethasone supersensitivity. Therefore, we examined the effect of age on the hypothalamic-pituitary-adrenal (HPA) system in depressed patients with and without PTSD. METHODS: Thirty-one depressed patients without PTSD, 12 depressed patients with PTSD, and 23 healthy volunteers were studied on 2 days. Subjects received single-blind placebo on day 1 and fenfluramine on day 2. Cortisol levels were drawn before challenge and for 5 h thereafter. RESULTS: Cortisol levels increase with age in depressed patients without PTSD but not in depressed patients with PTSD or in healthy volunteers. Number of previous major depressive episodes was a predictor of the cortisol response to fenfluramine administration in depressed patients without PTSD. CONCLUSIONS: The results of our study highlight the importance of considering age in psychobiology. Further research is needed to fully delineate the role of age in abnormalities of the HPA axis found in major depression and PTSD.     

Stress-buffering effects of psychosocial resources on physiological and psychological stress response in pregnant women

Sixty healthy pregnant women (aged 21-35 years), including 30 pregnant women at the beginning of second trimester and 30 women at the beginning of third trimester underwent a psychosocial stress test. Physiological (salivary free cortisol levels, salivary alpha-amylase levels) and psychological (perceived stress, mood, anxiety) responses to standardized psychosocial stress have been brought in association with psychosocial resources (self-efficacy and daily uplifts). Predictions revealed that higher resources predict lower physiological and psychological stress responses and higher mood levels. We conclude from our data that psychosocial resources appear to dampen psychological and physiological stress response during pregnancy.     

Circannual rhythm in the effects of stress on the humoral immune response of the rat

Among the seasonal immunological changes that have been observed are increase in spring-summer and decrease in autum-winter humoral response, in unstressed subjects. In rats we show that, relative to controls, stress increased the antibody response to sheep red blood cells in July–August, and decreases it from September throughout February. We concluded, therefore, that stress reinforces the basic annual rhythm of this type of response.     

Differential impact of the first and second wave of a stress response on subsequent fear conditioning in healthy men

Stress is a process of multiple neuroendocrine changes over time. We examined effects of the first-wave and second-wave stress response on acquisition and immediate extinction of differential fear conditioning, assessed by skin conductance responses. In Experiment 1, we placed acquisition either close to the (second-wave) salivary cortisol peak, induced by a psychosocial stressor (experimental group, EG), or after non-stressful pretreatment (control group, CG). Contrary to predictions, groups did not differ in differential responding. In the EG only, mean differential responding was negatively correlated with cortisol increases. In Experiment 2, we placed conditioning near the first-wave stress response, induced by a cold pressor test (CPT), or after a warm-water condition (CG). CPT-stress increased extinction resistance. Moreover, acquisition performance after CPT was positively correlated with first-wave blood pressure increases. Data suggest that mediators of the first-wave stress response enhance fear maintenance whereas second-wave cortisol responsivity to stress might attenuate fear learning.     

潜艇艇员心理应激与个性特征、应对方式及社会支持的关系研究

目的探讨潜艇艇员心理应激与个性特征、应对方式及社会支持的关系。方法对460名游艇艇员进行量表测评，包括心理社会应激调查表（PSSG）、卡特尔16种人格因素问卷（16PF）、特质应对问卷（TCSQ）和领悟社会支持量表（PSSS），数据采用SPSS15．0和Amos7．0进行统计分析。结果①潜艇艇员不同衔级组间心理应激水平存在高度显著性差异（F=12．12，P〈0．01），其中高级士官及军官组（51．46±25．19）心理应激水平最高，而义务兵组（35．63士16．94）最低；②潜艇艇员心理应激水平与适应与焦虑型（0．68）和消极应对（0．63）等呈高度显著性正相关，与内向与外向型（-0．41）、社会支持（-0．33）、积极应对（-0．32）和感情与安详型（-0．30）等呈高度显著性负相关；③多元逐步回归分析标准回归系数排在前3位的变量依次为：适应与焦虑型、消极应对、社会支持（标准回归系数依次为0．441、0．300、-0．107）；④路径分析显示适应与焦虑型对潜艇艇员心理应激既有直接效应又有间接效应，且以直接效应为主（总效应0．682，直接效应0．441）；消极应对和社会支持对心理应激具有直接效应（分别为0．300和-0．107）；积极应对和内向与外向型对心理应激具有间接效应（分别为-0．027和-0．005）。结论潜艇艇员心理应激水平受个性特征、应对方式及社会支持的影响。     

Influence of functional tryptophan hydroxylase 2 gene variation and sex on the startle response in children, young adults, and older adults

Serotonin, a key regulator of emotional behavior, is synthesized by tryptophan hydroxylase (TPH). Allelic variation of TPH2 gene expression influences serotonin synthesis in the brain and therefore may modulate emotional processing. Here, we investigated the influence of the −703 G/T polymorphism in the regulatory promoter region of the TPH2 gene on the startle response in three different age samples: children (N = 110), young adults (N = 209), and older adults (N = 95). Startle magnitudes to intense noise bursts were recorded during baseline and while participants viewed unpleasant, pleasant or neutral pictures. There was a significant TPH2 × sex interaction effect in young adults with male T allele carriers showing stronger overall startle responses compared to male G/G homozygotes while in young women this effect appeared to be reversed. The difference between TPH2 genotype groups also reached significance in the female subsample when including menstrual cycle phase. In contrast, there was no effect of TPH2 or a TPH2 × sex interaction effect in children or in older adults.     

Swimming exercise effects on the expression of HSP70 and iNOS in hippocampus and prefrontal cortex in combined stress

Exercise could play a beneficial role in stress, but its underlying mechanism especially about heat shock protein 70 (HSP70) and inducible nitric oxide synthase (iNOS) in brain has not been fully clarified. Moreover, few studies have investigated swimming exercise and its effects on the combined stress of both chronic and acute stress. In this study we tried to investigate the role of swimming exercise in combined stress and whether its biological mechanism was related to the HSP70 and iNOS in hippocampus and prefrontal cortex. 32 Wistar rats were enrolled and divided into four groups: control, CUMS, labetalol and exercise. After the animal model of chronic unpredicted mild stress (CUMS) was built in the latter three groups, all the rats were given the novel acute stress of inescapable footshock. The behavioral changes were measured by open field test. Radioimmunoassay (RIA) was adopted to test the change of serum corticosterone (CORT). The expression of HSP70 and iNOS in hippocampus and prefrontal cortex was analyzed by Western blot. The results demonstrated that swimming exercise could not only improve the behavior changes and protect the function of HPA axis stable in CUMS animals exposed to novel acute stress, but also increase the HSP70 expression and decrease the iNOS expression in hippocampus and prefrontal cortex. In conclusion, swimming exercise could play a beneficial role in combined stress by up-regulating HSP70 level and down-regulating iNOS level in brain.     

Effects of neonatal handling on the behavior and prolactin stress response in male and female rats at various ages and estrous cycle phases of females

Neonatal handling induces behavioral and hormonal changes, characterized by reduced fear in novel environments, and lesser elevation and faster return to basal levels of plasma corticosterone, prolactin and adrenaline, in response to stressors in adulthood. The present study aimed to analyze the effects of neonatal handling from Days 1 to 10 postnatal on prolactin response to ether stress in male and female rats at three life periods: neonatal, peripubertal and adulthood. Moreover, adult females were tested in two different phases of the estrous cycle, i.e., diestrus and estrus. In another set of experiments, the behavior of peripubertal and adult males and females in estrus and diestrus was analyzed in the elevated plus maze test. Pups were either handled for 1 min (handled group) or left undisturbed (nonhandled group) during the first 10 days after delivery. In adults, in the handled females in diestrus, stress induced a lesser increase in plasma prolactin compared with nonhandled ones, as in males. However, in estrus, handled females showed no difference in the prolactin response to stress. In the elevated plus maze, handled females in diestrus, but not in estrus, showed higher locomotor activity compared with nonhandled ones. Peripubertal male and female rats handled during the neonatal period showed no difference in behavior in the elevated plus maze compared with nonhandled animals. Early-life stimulation can induce long-lasting behavioral and stress-related hormonal changes, but they are not stable throughout life and phases of the estrous cycle.