The psychology in psychoneuroendocrinology

Individual differences in inflammatory and oxidative mechanisms of stress-related mood disorders

Emotional stress leads to the development of peripheral disorders and is recognized as a modifiable risk factor for psychiatric disorders, particularly depression and anxiety. However, not all individuals develop the negative consequences of emotional stress due to different stress coping strategies and resilience to stressful stimuli. In this review, we discuss individual differences in coping styles and the potential mechanisms that contribute to individual vulnerability to stress, such as parameters of the immune system and oxidative state. Initial differences in inflammatory and oxidative processes determine resistance to stress and stress-related disorders via the alteration of neurotransmitter content in the brain and biological fluids. Differences in coping styles may serve as possible predictors of resistance to stress and stress-related disorders, even before stressful conditions. The investigation of natural variabilities in stress resilience may allow the development of new methods for preventive medicine and the personalized treatment of stress-related conditions.

Biological clock function is linked to proactive and reactive personality types

Background

Many physiological processes in our body are controlled by the biological clock and show circadian rhythmicity. It is generally accepted that a robust rhythm is a prerequisite for optimal functioning and that a lack of rhythmicity can contribute to the pathogenesis of various diseases. Here, we tested in a heterogeneous laboratory zebrafish population whether and how variation in the rhythmicity of the biological clock is associated with the coping styles of individual animals, as assessed in a behavioural assay to reliably measure this along a continuum between proactive and reactive extremes.

Results

Using RNA sequencing on brain samples, we demonstrated a prominent difference in the expression level of genes involved in the biological clock between proactive and reactive individuals. Subsequently, we tested whether this correlation between gene expression and coping style was due to a consistent change in the level of clock gene expression or to a phase shift or to altered amplitude of the circadian rhythm of gene expression. Our data show a remarkable individual variation in amplitude of the clock gene expression rhythms, which was also reflected in the fluctuating concentrations of melatonin and cortisol, and locomotor activity. This variation in rhythmicity showed a strong correlation with the coping style of the individual, ranging from robust rhythms with large amplitudes in proactive fish to a complete absence of rhythmicity in reactive fish. The rhythmicity of the proactive fish decreased when challenged with constant light conditions whereas the rhythmicity of reactive individuals was not altered.

Conclusion

These results shed new light on the role of the biological clock by demonstrating that large variation in circadian rhythmicity of individuals may occur within populations. The observed correlation between coping style and circadian rhythmicity suggests that the level of rhythmicity forms an integral part of proactive or reactive coping styles.

Electronic supplementary material

The online version of this article (10.1186/s12915-018-0618-0) contains supplementary material, which is available to authorized users.

The AAA (appraisals, attributions, adaptation) model of job stress

The AAA model is presented as an integrative conceptualization of workplace stress that combines research from multiple models and theories to account for the numerous complexities that employees experience when cognitively evaluating organizational demands. The proposed model examines the effects of employees’ organizational stressors on the cognitive appraisal process and describes how employees’ emotions and self-regulation affect individual coping behaviors, adaptation, and learning from stressful experiences. Practitioner applications, theoretical contributions, and directions for future research are presented.

'Does religion cause health?': differing interpretations and diverse meanings

The question, 'Does religion (or spirituality) cause physical health benefits?' may be given at least four diverging interpretations in terms of causal path diagrams. In common usage, the question may be interpreted to indicate that religion causally influences health by: (1) any mechanism, including well-established factors such as social support and improved health behaviors; (2) additional mechanisms, such as enhanced positive psychological states (e.g. faith, hope, inner peace) acting through psychoneuroimmunologic or psychoneuroendocrinologic pathways; (3) offering psychological strength for acquiring or maintaining positive health behaviors; or (4) causally influencing health by distant healing or intercessory prayer. We review historical confusion between these interpretations, arguing that disentangling them is important for collaborative health care, promotion and research.

Perceived control moderates the influence of active coping on salivary cortisol response to acute pain among women but not men

It is generally established that active-coping strategies and greater perceived control over pain are associated with improved pain-related outcomes; however, it remains unclear whether these factors independently or interactively influence adrenocortical function in reaction to a painful stimulus. The present study examined whether active coping predicted magnitude cortisol response to acute pain, whether perceived control over pain moderated this association, and whether effects differed as a function of sex. Our findings suggest that perceived control moderates the active coping-adrenocortical relation among women but not men, such that active coping may augment the release of cortisol in response to a painful stimulus only in the presence of greater perceived control over pain. Taken together, active coping and perceived control may potentiate an adaptive neuroendocrine response to an acute painful stressor.

The effects of stress and coping on surgical performance during simulations

OBJECTIVE

This study investigates the effects of surgeons' stress levels and coping strategies on surgical performance during simulated operations.

METHODS

Thirty surgeons carried out each a non-crisis and a crisis scenario of a simulated operation. Surgeons' stress levels were assessed by several measures: self-assessments and observer ratings of stress, heart rate, heart rate variability, and salivary cortisol. Coping strategies were explored qualitatively and quantified to a coping score. Experience in surgery was included as an additional predictor. Outcome measures consisted of technical surgical skills using Objective Structured Assessment of Technical Skill (OSATS), nontechnical surgical skills using Observational Teamwork Assessment for Surgery (OTAS), and the quality of the operative end product using End Product Assessment (EPA). Uni- and multivariate linear regression were used to assess the independent effects of predictor variables on each performance measure.

RESULTS

During the non-crisis simulation, a high coping score and experience significantly enhanced EPA (beta1, 0.279; 0.009-0.460; P= 0.04; beta2, 0.571; 4.328-12.669, P< 0.001; respectively). During the crisis simulation, a significant beneficial effect of the interaction of high experience and low stress on all performance measures was found (EPA: beta, 0.537; 2.079-8.543; OSATS: beta, 0.707; 8.708-17.860; OTAS: beta, 0.654; 13.090-30.483; P< 0.01). Coping significantly enhanced nontechnical skills (beta, 0.302; 0.117-1.624, P= 0.03).

CONCLUSIONS

Clinicians' stress and coping influenced surgical performance during simulated operations. Hence, these are critical factors for the quality of health care.

AUDITORY INFORMATION PROCESSING IS ALTERED IN NOVELTY STRESS CONDITIONS: FIRST SESSION EFFECTS IN AUDITORY-EVOKED POTENTIALS

Novelty conditions may elicit stress responses. First session effects are systematic changes in physiological parameters, resulting from the interference of physiological processes with novelty stress. Along with endocrinological changes, these stress responses may be accompanied by alterations of sensory and attentional processes. The present study examines the impact of novelty conditions on event-related potential indicators of auditory information processing and on cortisol. Twenty-two healthy subjects participated in a series of experimental sessions. Auditory-evoked potentials were recorded, and the plasma cortisol levels were determined. The first session causes an activation of the hypothalamo-hypopituitary-adrenal axis. The auditory-evoked potentials show an additional slow negative potential component in the novelty condition. This potential component is maximal at fronto-central electrode sites and reaches its peak at about 240 ms after stimulus onset. Similarities with the processing negativity suggest alterations in attention-related auditory information-processing in the novelty condition encountered in the first session.

Cortisol as a marker for improvement in mindfulness-based stress reduction

While much attention has been devoted to examining the beneficial effects of Mindfulness-Based Stress Reduction programs on patients' ability to cope with various chronic medical conditions, most studies have relied on self-report measures of improvement. Given that these measures may not accurately reflect physiological conditions, there is a need for an objective marker of improvement in research evaluating the beneficial effects of stress management programs. Cortisol is the major stress hormone in the human organism and as such is a promising candidate measure in the study of the effects of Mindfulness-Based Stress Reduction programs. In conjunction with other biological measures, the use of cortisol levels as a physiological marker of stress may be useful to validate self-reported benefits attributed to this program. In the current manuscript, we review the available literature on the role of cortisol as a physiological marker for improvement with regards to mindfulness practice, and make recommendations for future study designs.

Effects of perceived control and cognitive coping on endocrine stress responses to pharmacological activation

BACKGROUND

The hypothalamic-pituitary-adrenal (HPA) axis may mediate negative health effects of stress. It is sensitive to cognitive/emotional factors like novelty, perceived control, and coping. Psychological intervention that reduces novelty and enhances cognitive coping and sense of control can reduce cortisol responses to pentagastrin, a pharmacological HPA activator. This study attempted to identify the core factors that modulate HPA axis activity in this model.

METHODS

Varying instructions were administered prior to drug exposure in a two-visit (placebo first) pentagastrin infusion paradigm. Healthy subjects (n = 40) were randomly assigned to one of four instruction groups: 1) standard instruction (SI); 2) full cognitive intervention (CI); 3) the CI control component alone; or 4) the CI novelty reduction/coping components alone. Blood samples were obtained via intravenous catheter before and after pentagastrin.

RESULTS

Subjects receiving an intervention had smaller cortisol responses than subjects receiving standard instructions. Coping alone had as strong an impact as the more complex intervention that combined coping and control. Control alone also reduced cortisol but its HPA impact appeared less robust.

CONCLUSIONS

Brief psychological manipulation can significantly reduce HPA activation in challenge paradigms. Cognitive preparation that focused on side effects, reduced potential surprise, and enhanced cognitive coping modulated HPA axis activity as effectively as a previously tested intervention that combined coping and control manipulations. A sense of control alone also reduced cortisol release. The results support development of control or coping techniques to combat negative health effects of stress that are mediated by HPA axis activation.

Coping with competition: neuroendocrine responses and cognitive variables

Confronting another individual or group motivated by the same goal is a very frequent situation in human communities that occurs in many other species. Competitive interactions emerge as critical situations that shed light on the effects and consequences of social stress on health. But more important than the situation itself is the way it is interpreted by the subject. This "appraisal" involves cognitive processes that contribute to explaining the neuroendocrine response to these interactions, helping to understanding the vulnerability or resistance to their effects. In this review, we defend the need to study human competition within the social stress framework, while maintaining an evolutionary perspective, and taking advantage of the theoretical and methodological advances in psychology and psychophysiology in order to better understand the cognitive processes underlying the social stress response in humans.

The moderating impact of emotional intelligence on free cortisol responses to stress

The construct of trait emotional intelligence (trait EI) refers to the individual differences in the perception, processing, regulation and utilization of emotional information. Several studies have found that trait EI was a significant moderator of subjective responses (e.g., mood deterioration, emotional intensity, action tendencies, bodily sensations) to both natural and laboratory stressors. The present study aims at extending these findings by examining whether trait EI also moderates the biological (i.e., cortisol) response to stress. To this end, 56 participants were assigned to either a neutral or a stressful condition (public speech task) and psychological and cortisol reactivity were examined. Results revealed that higher trait EI scores were associated with significantly lower reactivity to stress at both psychological (i.e., mood deterioration) and biological (i.e., salivary cortisol) levels. Additional analyses revealed that trait EI had incremental validity to predict stress reactivity over and above social desirability, alexithymia and the five-factor model of personality.

Historical approach and evolution of the stress concept: a personal account

As a matter of research or as a process, stress remains one of the most cited construct in biomedical literature; a medline survey accounts for more than 210,000 citations since 1970. It is difficult to define. It is frequently used in a vague manner, including undifferently the agent, the process, and the response. The concept is multidimensional and composite, including emotion and arousal. Stress has an implicit: it implies alteration of a theoretical balance or equilibrium within physiological systems, and it seems to characterize a process leading to disease. Large individual differences exist in the way to react to a stressor. Psychological and cognitive determinants are central for the course of the process. The homeostasis concept is not useful anymore and has been replaced by the more accurate and flexible concept of allostasis. The physiological hormonal and neural bases of this process are now identified. New perspectives identify stressors, chronic or not, to be a source of vulnerabilities through epigenetic mechanisms and a series of biobehavioral disorders characteristic of our modern civilizations. The evolution of the concept is not linear. It has been enriched by recent neurobiological-neuroendocrinological discoveries and also by behavioral-cognitive sciences.

Glucocorticoid levels in free ranging resident mantled howlers: a study of coping strategies

A growing amount of data shows that a preference for passive-nonaggressive over active-aggressive problem solving is associated with higher levels of glucocorticoids (GC). For mantled howlers, the arrival of an adult male in a new group is a potential source of psychological stress for both resident males and females. Resident mantled howler males take an active stand and aggressively repel the entrance of solitary males, while females take a passive-nonaggressive stand. In order to study whether the relationship between coping strategies and the activation of the hypothalamic-pituitary-adrenal (HPA) axis observed in other species applies to the response of resident mantled howlers to the presence of solitary males, we examine the relationship between different group and subpopulation variables and the GC levels measured in feces collected from 10 groups living in six forest fragments, in Los Tuxtlas, Mexico. The results of our study suggest that the resident mantled howler females' passive response to the presence of solitary males is accompanied by the activation of the HPA axis, whereas resident males' aggressive response is not accompanied by any changes in the HPA axis. In contrast, a previous study suggests that resident male howlers respond by increasing their testosterone levels to the presence of solitary males (Cristobal-Azkarate et al., Hormones and Behavior 2006;49 261-267). These different behavioral and hormonal responses coincide with the active and passive coping styles described for other species. The conditions in which howlers live in our study area may be favoring the interaction between solitary and resident howlers, and inducing chronically high GC levels, which in turn could negatively affect the fitness of these subpopulations.

Neurosteroids, neuroactive steroids, and symptoms of affective disorders

Neurosteroids (NS) are steroids synthesized by the brain. Neuroactive steroids (NAS) refers to steroids that, independent of their origin, are capable of modifying neural activities. NAS bind and modulate different types of membrane receptors. The gamma amino butyric acid (GABA) and sigma receptor complexes have been the most extensively studied. Oxidized ring A reduced pregnanes, tetrahydroprogesterone (THP), and tetrahydrodeoxycorticosterone (THDOC) bind to the progesterone intracellular receptor (PR), and in this way can also regulate gene expression. Animal experimentation showed that salient symptoms of depression, viz., anxiety, sleep disturbances, and memory and sexual dysfunctions, are modulated by NAS. In turn, psychotropic drugs modulate NS and NAS levels. NS levels as well as NAS plasma concentrations change in patients with depression syndromes, the levels return to normal baseline with recovery, but normalization is not necessary for successful therapy. Results from current studies on the evolution of nervous systems, including evolutionary developmental biology as well as anatomical and physiological findings, almost preclude a categorical classification of the psychiatric ailments the human brain succumbs to. The persistence in maintaining such essentialist classifications may help to explain why up to now the search for biological markers in psychiatry has been an unrewarding effort. It is proposed that it would be more fruitful to focus on relationships between NAS and symptoms of psychiatric disorders, rather than with typologically defined disorders.

Paramedic performance in calculating drug dosages following stressful scenarios in a human patient simulator

BACKGROUND

Paramedics face many stressors in their work environment. Studies have shown that stress can have a negative effect on the psychological well-being of health professionals. However, there is little published research regarding the effects of stress on the cognitive skills necessary for optimal patient care.

OBJECTIVES

The primary purpose of this study was to investigate the effects of acute stress on the emotional response and performance of paramedics. Furthermore, the authors explored whether a paramedic's level of training or years of experience would mediate the effects of stress on performance.

METHODS

Paramedic performances in calculating drug dosages were compared in two stress conditions. In the low-stress condition, 30 paramedics calculated the drug dosages in a quiet classroom free of any stressor. In the high-stress condition, the same paramedics calculated comparable drug dosages immediately after working through a challenging scenario with a human patient simulator.

RESULTS

The paramedics obtained lower accuracy scores in the high-stress condition than in the low-stress condition [43% (95% confidence interval [CI]: 36.9-49.2) vs. 58% (95% CI: 48.6-67.1), p < 0.01 based on univariate analysis]. Neither work experience nor level of training predicted the individual differences in the stress-induced performance decrements.

CONCLUSION

These results suggest that the types of stressors encountered in clinical situations can increase medical errors, even in highly experienced individuals. These findings underline the need for more research to determine the mechanisms by which stress influences clinical performance, with the ultimate goal of targeting education or technologic interventions to those tasks, situations, and individuals most likely to benefit from such interventions.

Psychological determinants of the cortisol stress response: the role of anticipatory cognitive appraisal

Psychosocial stress is a potent activator of the hypothalamus-pituitary-adrenal (HPA) axis. While the physiological mechanisms of HPA axis responses to stress as well as its short and long-term consequences have been extensively examined, less is known why someone elicits an acute neuroendocrine stress response, i.e. what are the psychological processes involved and how are they related to the acute neuroendocrine stress response. To examine this question, a questionnaire to assess anticipatory cognitive appraisal processes was developed and administered to 81 male healthy subjects in a standardized psychosocial stress situation (Trier social stress test). Cortisol stress responses were assessed with repeated measurement of salivary free cortisol. Hierarchical regression analyses show that anticipatory cognitive appraisal, in contrast to general personality factors and retrospective stress appraisal is an important determinant of the cortisol stress response, explaining up to 35% of the variance of the salivary cortisol response. The reported results emphasize the importance of psychological stress processing for the understanding of psychobiological stress responses. Since stress and its biological consequences have been shown to be associated with the onset and the maintenance of somatic illnesses and psychiatric disorders, psychological processes are prime targets for prevention and intervention.

Coping with competitive situations in humans

The analysis of effects of competitive situations in our species may contribute to acquiring deeper knowledge about the effects of social stress and its relationship with different pathologies. The latest studies indicate that the neuroendocrine response to competition depends more on subjective factors related to the cognitive evaluation of the situation than on the outcome itself. Findings suggest that when subjects cope with a competition, they assess it in such a way that it activates a psychobiological coping response. The pattern of this response may correspond to a predominant active or passive coping strategy, the choice ultimately depending on factors such as the importance of the competition for the subject, the subject's involvement or perceived possibilities of control of outcome or success (e.g. past experience in similar competitions, judge or rank of the opponent), among others. More important than winning or losing is the coping pattern displayed by the subject, which determines the hormonal changes experienced when facing competition and its outcome.

Steroids, neuroactive steroids and neurosteroids in psychopathology

The term "neurosteroid" (NS) was introduced by Baulieu in 1981 to name a steroid hormone, dehydroepiandrosterone sulfate (DHEAS), that was found at high levels in the brain long after gonadectomy and adrenalectomy, and shown later to be synthetized by the brain. Later, androstenedione, pregnenolone and their sulfates and lipid derivatives as well as tetrahydrometabolites of progesterone (P) and deoxycorticosterone (DOC) were identified as neurosteroids. The term "neuroactive steroid" (NAS) refers to steroids which, independent of their origin, are capable of modifying neural activities. NASs bind and modulate different types of membrane receptors. The GABA and sigma receptor complexes have been the most extensively studied, while glycine-activated chloride channels, nicotinic acetylcholine receptors, voltage-activated calcium channels, although less explored, are also modulated by NASs. Within the glutamate receptor family, N-methyl-d-aspartate (NMDA) receptors, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors and kainate receptors have also been demonstrated to be a target for steroid modulation. Besides their membrane effects, once inside the neuron oxidation of Ring A reduced pregnanes, THP and THDOC, bind to the progesterone intracellular receptor and regulate gene expression through this path. The involvement of NASs on depression syndromes, anxiety disorders, stress responses to different stress stimuli, memory processes and related phenomena such as long-term potentiation are reviewed and critically evaluated. The importance of context for the interpretation of behavioral effects of hormones as well as for hormonal levels in body fluids is emphasized. Some suggestions for further research are given.

Avoidance behavior and brain monoamines in fish

The crucian carp performs a typical avoidance behavior when exposed to olfactory cues from injured skin of conspecifics. They swim rapidly to the bottom and hide in available material. This work examines the effects of skin extract exposure and availability of hiding material on this behavior, and concomitant changes in brain monoaminergic activity in crucian carp. Individual fish were exposed to skin extract in aquaria with or without hiding material. Exposure to skin extract resulted in the expected avoidance behavior consisting of rapid movement towards the bottom of the aquarium. This lasted for 1-2 min. Activity then decreased below the level observed before exposure, suggesting a "freezing" type of avoidance behavior. This behavior was independent of availability of hiding material. Brain dopaminergic activity increased in telencephalon and decreased in the brain stem following skin extract exposure, again independent of availability of hiding material. However, fish kept in aquaria without hiding material showed an elevation of serotonergic activity in the brain stem and the optic tectum compared to fish with available hiding material. Absence of hiding material increased serotonergic activity also without exposure to skin extract. In aquaria with hiding material, the fish stirred up a cloud of fine sediments and showed a more pronounced decrease in locomotor activity in agreement with this being a more efficient freezing or immobile avoidance behavior. These results show that basic components of avoidance behavior and related brain changes are present in the fish brain, in accordance with the common phylogenetic roots of avoidance behavior in all vertebrates.

Acute HPA axis responses, heart rate, and mood changes to psychosocial stress (TSST) in humans at different times of day

There is evidence showing that HPA axis responses to pharmacological provocation depend on time of day with larger cortisol responses in the afternoon and evening compared to the morning hours. However, it is still unknown whether HPA axis responses to psychological stress are affected by time of day and whether they can be assessed with equal reliability in the morning and afternoon, respectively. The present reanalysis is based on five independent studies conducted in the same laboratory by and. All subjects were confronted with the Trier Social Stress Test (TSST) either in the morning or in the afternoon. The total sample consisted of 180 adults with 115 younger (49 females, 66 males) and 65 older adults (32 females, 33 males). All ANCOVA results controlled for possible age and gender effects. Stress-related free salivary cortisol, total plasma cortisol and ACTH net increases did not differ according to time of day (all p = n.s.). However, as expected pre-stress free salivary and total plasma cortisol levels differed significantly between the morning and afternoon group (both p < 0.005), leading to a significantly higher free cortisol area under the curve (AUC) in the morning (p = 0.02). Taken together, these observations suggest that the adrenal glands may be more sensitive to ACTH in the morning. Additionally, higher basal salivary cortisol levels were related to a lower stress-related net increase in salivary cortisol (p = 0.02), total plasma cortisol (p < 0.0001), and marginally ACTH (p = 0.09). Stress-related heart rate increases did not differ between groups (p = n.s.). The finding that the TSST-induced mood change was differentially affected by time of day requires further exploration. We conclude that comparable HPA axis and heart rate stress responses to psychosocial stress can be measured in the morning and afternoon.

Psychobiological mechanisms of socioeconomic differences in health

The association between low socioeconomic status and poor health is well established. Empirical studies suggest that psychosocial factors are important mediators for these effects, and that the effects are mediated by psychobiological mechanisms related to stress physiology. The objective of this paper is to explore these psychobiological mechanisms. Psychobiological responses to environmental challenges depend on acquired expectancies (learning) of the relations between responses and stimuli. The stress response occurs whenever an individual is faced with a challenge. It is an essential element in the total adaptive system of the body, and necessary for adaptation, performance and survival. However, a period of recovery is necessary to rebalance and to manage new demands. Individuals with low social status report more environmental challenges and less psychosocial resources. This may lead to vicious circles of learning to expect negative outcomes, loss of coping ability, strain, hopelessness and chronic stress. This type of learning may interfere with the recovery processes, leading to sustained psychobiological activation and loss of dynamic capacity to respond to new challenges. Psychobiological responses and health effects in humans and animals depend on combinations of demands and expected outcomes (coping, control). In studies of humans with chronic psychosocial stress, and low SES, cortisol baseline levels were raised, and the cortisol response to acute stress attenuated. Low job control was associated with insufficient recovery of catecholamines and cortisol, and a range of negative health effects. Biological effects of choice of lifestyle, which also depends on the acquired outcome expectancies, reinforce these direct psychobiological effects on health. The paper concludes that sustained activation and loss of capacity to respond to a novel stressor could be a cause of the higher risk of illness and disease found among people with lower SES.

The cognitive activation theory of stress

This paper presents a cognitive activation theory of stress (CATS), with a formal system of systematic definitions. The term "stress" is used for four aspects of "stress", stress stimuli, stress experience, the non-specific, general stress response, and experience of the stress response. These four meanings may be measured separately. The stress response is a general alarm in a homeostatic system, producing general and unspecific neurophysiological activation from one level of arousal to more arousal. The stress response occurs whenever there is something missing, for instance a homeostatic imbalance, or a threat to homeostasis and life of the organism. Formally, the alarm occurs when there is a discrepancy between what should be and what is-between the value a variable should have (set value (SV)), and the real value (actual value (AV)) of the same variable. The stress response, therefore, is an essential and necessary physiological response. The unpleasantness of the alarm is no health threat. However, if sustained, the response may lead to illness and disease through established pathophysiological processes ("allostatic load"). The alarm elicits specific behaviors to cope with the situation. The level of alarm depends on expectancy of the outcome of stimuli and the specific responses available for coping. Psychological defense is defined as a distortion of stimulus expectancies. Response outcome expectancies are defined as positive, negative, or none, to the available responses. This offers formal definitions of coping, hopelessness, and helplessness that are easy to operationalize in man and in animals. It is an essential element of CATS that only when coping is defined as positive outcome expectancy does the concept predict relations to health and disease.

From hormones to immunity: the physiology of immunology

Discoveries in the physiology of immunology have increased at an increasing rate during the past two decades. It is now recognized that the immune system is just another physiological system that regulates, and is regulated by, other physiological systems such as the brain. These advances make it clear that recent findings in genomic biology must be interpreted in the context of the environment in which animals and humans live. Lack of a strong genetic basis for significant human mental health disorders, such as major depression, points to the critical importance of interactions. Several examples of environmental x genetic x disease interactions are presented. Regulation of cells of the hematopoietic lineage by two genes that control over 80% of postnatal growth, growth hormone and IGF-I, are then highlighted. The reciprocal relationship of how proinflammatory cytokines from the immune system regulate the growth hormone/IGF-I axis is also summarized. Particular emphasis is placed upon TNFalpha-induced IGF-I resistance in neurons, muscle cells and epithelial cells. This cytokine regulation of hormone action may ultimately be more important for human and animal health than direct effects of growth hormone and IGF-I on hematopoietic cells. Wasting of AIDS patients is given as an important clinical example of how TNFalpha from an activated immune system reduces IGF-I sensitivity in multiple physiologic systems, including muscle, nervous and hematopoietic tissues.

Stop that! Inhibition, sensitization, and their neurovisceral concomitants

There is increasing evidence that the behavior of living systems can be conceptualized as a self-organizing dynamical system. Moreover, evidence suggests that inhibitory processes give these systems the flexibility that is necessary for efficient functioning in the face of changing environmental demands. The process of sensitization can be conceived as a breakdown of inhibitory neural processes that can lead to maladaptive, perseverative behavior. In this paper we describe a model of inhibition and sensitization from a dynamical systems perspective. We show that inhibition is important for adaptive behavior across a number of levels of system functioning. Using our work on attention, emotion, and anxiety disorders we show the importance of both central - for example gamma-aminobutyric acid (GABA)-ergic - and peripheral - for example heart rate variability (HRV) - inhibitory processes and how they may be linked by a network of neural structures that guide the organism from one state of relative stability to another.

Behavior and cortisol levels of dogs in a public animal shelter, and an exploration of the ability of these measures to predict problem behavior after adoption

Behavior and plasma cortisol levels were examined in puppies and juvenile/adult dogs admitted to a public animal shelter. A behavioral test was developed to assess the responses of the dogs to novel or threatening conditions. Factor analysis of the behavioral responses of 166 dogs on day 3 in the shelter yielded six factors (locomotor activity, flight, sociability, timidity, solicitation, and wariness) that accounted for 68% of the total variance. Among those dogs remaining in the shelter for 9 days, plasma cortisol levels declined from day 2 to 9. Cortisol levels were weakly related to factor scores. In order to explore the relation of measures in the shelter to later behavior, questionnaires assessing problem behaviors were mailed to new owners of dogs 2 weeks and 6 months following adoption. Among puppies, wariness scores were negatively correlated with behavior problems at 2 weeks and cortisol levels were negatively correlated with behavior problems at 6 months. These results suggest how measures of behavior and endocrine activity obtained in shelters might prove useful for screening dogs for adoption or targeting dogs for behavioral intervention.

The relation between work-induced neuroendocrine reactivity and recovery, subjective need for recovery, and health status

OBJECTIVES

The purpose of this cross-sectional study with repeated measurements was to find out to what extent neuroendocrine reactivity during work and neuroendocrine recovery from work, and work characteristics, are related to subjective need for recovery and perceived health status.

METHODS

Neuroendocrine reactivity and recovery were studied in 59 subjects by measuring urinary adrenaline and cortisol repeatedly during five consecutive days. Measures of work characteristics, subjective need for recovery, and health status were obtained by self-reports. Two hierarchical multiple linear regression analyses were performed.

RESULTS

The work characteristics alone explained 39% and 28% of the variation in subjective need for recovery and health status, respectively, while these figures rose to 49% and 53% in the full models. Significant neuroendocrine contributors were found for cortisol in reactivity during work and recovery immediately after work and recovery during the day off-work, and for adrenaline in baseline level and recovery during the day off-work. Job characteristics contributed significantly as well.

CONCLUSION

Both neuroendocrine measures and work characteristics were predictors for the amount of perceived need for recovery after work as well as for health status. The results are consistent with the cognitive activation theory of stress.

The specificity of stress responses to different nocuous stimuli: neurosteroids and depression

The role that adrenal cortex and neurosteroid hormones may have in the etiology and/or maintenance of depressive diseases is discussed. Selye's concept of stress as the summation of unspecific body responses of the autonomic central nervous system (CNS) and hypothalamic pituitary adrenal axis (HPAA) as the main characteristic of it is contrasted with Mason's view of stress responses as being specific for different stimuli, i.e., the neuroendocrine system responds with the production of a hormonal profile individualized and characteristic for the various stimuli applied. The data reviewed provides support for Mason's interpretation of stress as fundamentally a behavioral response. In turn, the high relevance of emotional factors in the determination of stress responses led to a reconsideration of cognitive-affective interactions in nervous systems. Recent results revealed that improvement in depression treated with antidepressants (ADs) is associated with an increase in the neurosteroid 3alpha 5alpha tetrahydroprogesterone, both in the blood and cerebrospinal fluid of recovered patients. The increase occurs with both selective serotonin reuptake inhibitors and tricyclic ADs. An evaluation of the possible and putative roles for neurosteroids in the CNS is presented and suggestions for enhancing the type of supporting data from the laboratory diagnosis of depressions are advanced.

Coping styles in animals: current status in behavior and stress-physiology

This paper summarizes the current views on coping styles as a useful concept in understanding individual adaptive capacity and vulnerability to stress-related disease. Studies in feral populations indicate the existence of a proactive and a reactive coping style. These coping styles seem to play a role in the population ecology of the species. Despite domestication, genetic selection and inbreeding, the same coping styles can, to some extent, also be observed in laboratory and farm animals. Coping styles are characterized by consistent behavioral and neuroendocrine characteristics, some of which seem to be causally linked to each other. Evidence is accumulating that the two coping styles might explain a differential vulnerability to stress mediated disease due to the differential adaptive value of the two coping styles and the accompanying neuroendocrine differentiation.