Stress, emotion, and human immune function

This article provides a review of empirical evidence linking emotional processes to immune function in humans. Acute stressors have produced mixed effects on immunity, presumably through differential activation of physiological stress systems. Chronic stress has been associated with suppression of immune function, and there is evidence that the immune system may not adapt over time. Effects of stress accompanying social disruption and psychological depression, when demonstrated, have been consistently adverse. Certain personality styles may enhance or degrade immune response. Relationships between psychosocial factors and immunity have been identified for several diseases, including cancer, acquired immune deficiency syndrome, and autoimmune diseases; psychosocial interventions have been tested with variable results. Theoretical and methodological considerations are summarized and directions for future research suggested.     

Stress, reactivity, and immune function in healthy men.

We examined the effects of acute psychological stress on lymphocyte proliferation and circulating levels of interleukin-1 and -2. Healthy men were exposed to two viewings of a gruesome surgery film and were asked to recall details of the film twice during a 30-min period. These subjects were compared to a nonstress control group. Lymphocyte proliferation to the mitogen concanavalin A (Con A; 5 micrograms/ml) was decreased during and after exposure to the stressor when compared to the control group. This decrease was more pronounced in subjects exhibiting greater blood pressure reactivity while viewing the film than in subjects showing smaller blood pressure responses. None of the other immunological measures was significantly affected by the stressor. Cortisol was not correlated with lymphocyte responsiveness. Possible explanations for these results and implications for further research are discussed.     

Stress, glucocorticoids and ageing of the immune system

Ageing has been associated with immunological changes (immunosenescence) that resemble those observed following chronic stress or glucocorticoid (GC) treatment. These changes include thymic involution, lower number of na?ve T cells, reduced cell-mediated immunity, and poor vaccination response to new antigens. It follows that immunosenescence could be associated with changes of peripheral GC levels. Indeed, when compared with young subjects, healthy elders are more stressed and show activation of the hypothalamus-pituitary-adrenal (HPA) axis. However, both beneficial and undesirable effects of GCs ultimately depend on the target tissue sensitivity to these steroids. Recent data indicate that peripheral lymphocytes from elders respond poorly to GC treatment in vitro. The present review summarizes recent findings which suggest that immunosenescence may be closely related to both psychological distress and stress hormones. Furthermore, chronically stressed elderly subjects may be particularly at risk of stress-related pathology because of further alterations in GC-immune signalling. Finally, the neuroendocrine hypothesis of immunosenescence is finally reconsidered in which the age-related increase in the cortisol/DHEA ratio is major determinant of immunological changes observed during ageing.     

Handedness and immune function

Geschwind, Galaburda, and Behan (GBG) have suggested that in utero levels of testosterone influence both cerebral and immune system developments (Geschwind and Behan, 1982; Geschwind and Galaburda, 1984; Geschwind and Galaburda, 1985). According to this theory, high levels of testosterone result in greater incidences of left-handedness, deviations from standard distribution of cerebral functions (known as anomalous dominance), and increased autoimmune dysfunction. While the original data supported these assertions, more recent tests of the hypothesis have been equivocal. One criticism of these studies is that the definition of both handedness and anomalous dominance are too vague. It was one of the aims of this project to investigate and clarify the GBG model by examining four different aspects of handedness as well as a more direct measure of anomalous dominance. In order to extend the GBG model, degree of left-handedness, general immune system functioning, and current testosterone levels were also examined. First, it was predicted and found that left handers had a higher incidence of autoimmune diseases in their immediate families than did right handers. Second, those left handers with an incidence of at least one autoimmune disease were more strongly left-handed than were those with no incidence of autoimmunity. Finally, it was observed that higher testos terone levels were supportive of general immunity. The present findings both support and expand the GBG model.     

The mind and the immune system

Stress-induced brain-mediated immunoregulation is effected by two pathways: autonomic outflow and (neuro)endocrine outflow. Particular attention is given to the interaction-effects of chronic an acute stress. Recent data have established that cells of the immune system produce neuro-peptides and hormones. In concert with cytokines released by these immune cells the brain can be informed on the nature of ongoing immune activity. The significance of conditioning of immune responses is discussed.     

Psychological interventions and the immune system: a meta-analytic review and critique.

This article reviews evidence for the hypothesis that psychological interventions can modulate the immune response in humans and presents a series of models depicting the psychobiological pathways through which this might occur. Although more than 85 trials have been conducted, meta-analyses reveal only modest evidence that interventions can reliably alter immune parameters. The most consistent evidence emerges from hypnosis and conditioning trials. Disclosure and stress management show scattered evidence of success. Relaxation demonstrates little capacity to elicit immune change. Although these data provide only modest evidence of successful immune modulation, it would be premature to conclude that the immune system is unresponsive to psychological interventions. This literature has important conceptual and methodological issues that need to be resolved before any definitive conclusions can be reached.     

Sick body, vigilant mind: the biological immune system activates the behavioral immune system

Activation of the behavioral immune system has been shown to promote activation of the biological immune system. The current research tested the hypothesis that activation of the biological immune system (as a result of recent illness) promotes activation of the behavioral immune system. Participants who had recently been ill, and had therefore recently experienced activation of their biological immune system, displayed heightened attention to (Study 1) and avoidance of (Study 2) disfigured individuals--cognitive and behavioral processes reflecting activation of the behavioral immune system. These findings shed light on the interactive nature of biological and psychological mechanisms designed to help people overcome the threat of disease.     

Social support and immune function among spouses of cancer patients

This study investigated whether social support was related to immune function among spouses of cancer patients. Effects of depression and negative life events were examined as potential mediators. Results showed evidence of greater immunocompetence on 2 of 3 dynamic measures: natural killer cytotoxicity and proliferation response to phytohemagglutinin among spouses who reported high levels of social support. All six components of social support assessed by the Social Provisions Scale (Cutrona & Russell, 1987) were strongly related to these indices of immune function. No evidence was found for mediation by either life events or depression.     

Fitts' law as a function of system dynamics and target uncertainty

Fins' law was found to hold for discrete movements executed by subjects controlling the velocity of a cursor with a control stick The slope of movement time versus index of difficulty was approximately twice as large as for a comparable position control system. Target uncertainty also increased the slope of total time versus index of difficulty, and this effect is interpreted in terms of adaptive tuning of the human movement system.     

Depression and HIV infection: impact on immune function and disease progression

Can psychological factors, such as depression, affect human immunodeficiency virus progression? HIV infection is viewed as a chronic illness in which those infected often confront a number of emotional challenges and physical health and disease-related issues. Over the past 20 years, there has been increasing evidence that depression and other mood-related disturbances are commonly observed among HIV-positive individuals. There is also mounting data showing that depressive symptoms might further impact upon specific elements of immune system functioning and influence quality of life and health status. This paper will highlight studies examining the prevalence of depression during HIV infection and review some of the evidence examining the impact of depressive symptoms on immune function and HIV disease progression.     

Visual detection as a function of attentional demand and perceptual system error

Attentional demands were varied in a two-alternative, forced-choice detection experiment. A bar indicator designated the target form in one condition and occurred in random locations in a second condition. Exposure durations necessary for predetermined single-form display HRs were determined for each of eight Ss to measure performance at different levels of perceptual system error. Forms differed in only a single feature. Detection was superior when the bar indicator designated the target form, and differences increased with increased display size. Evidence for interference in detection due to the presence of nontarget forms apart from noting requirements of such forms was found. Estimates of number of perceptual channels noted did not clearly differentiate serial from parallel processing models. It was concluded that display interference error and spatial selectivity influences are important determinants of detection accuracy.     

The behavioral immune system: Current concerns and future directions

The behavioral immune system is a motivational system that helps minimize infection risk by changing cognition, affect, and behavior in ways that promote pathogen avoidance. In the current paper, we review foundational concepts of the behavioral immune system and provide a brief summary of recent social psychological research on this topic. Next, we highlight current conceptual and empirical limitations of this work and delineate important questions that have the potential to drive major advances in the field. These questions include predicting the ontological development of the behavioral immune system, specifying the relationship between this system and the physiological immune system, and distinguishing conditions that elicit direct effects of situational pathogen threats versus effects that occur only in interaction with dispositional disease concerns. This discussion highlights significant challenges and underexplored topics to be addressed by the next generation of behavioral immune system research.     

Psychological stress and the human immune system: a meta-analytic study of 30 years of inquiry

The present report meta-analyzes more than 300 empirical articles describing a relationship between psychological stress and parameters of the immune system in human participants. Acute stressors (lasting minutes) were associated with potentially adaptive upregulation of some parameters of natural immunity and downregulation of some functions of specific immunity. Brief naturalistic stressors (such as exams) tended to suppress cellular immunity while preserving humoral immunity. Chronic stressors were associated with suppression of both cellular and humoral measures. Effects of event sequences varied according to the kind of event (trauma vs. loss). Subjective reports of stress generally did not associate with immune change. In some cases, physical vulnerability as a function of age or disease also increased vulnerability to immune change during stressors.     

Stress management effects on psychological, endocrinological, and immune functioning in men with HIV infection: empirical support for a psychoneuroimmunological model

We present a psychoneuroimmunologic (PNI) model for Human Immunodeficiency Virus (HIV) infection, describe a 10-week group-based cognitive behavioral stress management (CBSM) intervention and summarize research demonstrating the effects of this intervention on mood, neuroendocrine (Hypothalamic Pituitary Adrenal [HPA], Hypothalamic Pituitary Gonadal [HPG] and Sympathetic Nervous System [SNS] hormones) and immune system status (lymphocyte subsets, anti-viral immune function) in HIV-infected persons. This work demonstrates that changes in relaxation skills, cognitive coping strategies and social support may mediate the mood effects of CBSM, and that these mood changes may mediate adrenal hormone regulation indicated by reductions in 24-h urinary cortisol (with reduced depressed mood) and norepinephrine (with reduced anxiety) and increases in serum DHEA-S and testosterone levels (with reduced depressed mood). Results also suggest that CBSM-related changes in production of these hormones may explain, in part, the effects of this intervention on short-term changes in IgG antibody titers to herpesviruses (with increased DHEA-S-to-cortisol ratio), and longer-term changes in lymphocyte subpopulations such as CD8 suppressor/cytotoxic cells (with reductions in urinary noradrenaline output) and transitional na?ve CD4 cells (with reductions in urinary cortisol output). Thus a multi-modal CBSM intervention is associated with alterations in mood, neuroendocrine functioning and immunologic status that may have health implications for HIV infection.     

The missing sense modality: the immune system

The five senses were handed down by Aristotle. I argue that it has only taken two millennia to recognize that the immune system has been the hidden sensory modality. The immune system completes the range of operation allowing detection of meaningful entities at all distances, from very near to very far. It also withstands the often implicit criteria for being a sense modality. Finally, cross-modal interactions between the immune system and vision and other sense modalities should be possible, opening up new research directions.     

行为免疫系统理论及其研究:新视野下的再考察

行为免疫系统理论认为, 为了应对流行病威胁, 人类进化出了一套特殊的行为反应倾向, 包括对疾病线索的警觉、厌恶, 对健康配偶的偏好, 对外群体的排斥, 对集体主义的推崇等。已有研究主要从宏观(群体)和微观(个体)两个水平开展, 虽然有大量研究结果支持该理论, 但也存在不少不一致甚至相反的发现。研究方法、理论基础和现代适用性等方面的不足可能是出现这种情况的原因。未来研究需克服上述问题, 并进一步拓展该理论的研究内容, 检验理论和相关研究的边界, 探讨行为免疫背后的生理机制等。     

An investigation of immune system disorder as a "marker" for anomalous dominance

Geschwind and Galaburda (1987) proposed that immune disorder (ID) susceptibility, along with left handedness and familial sinistrality (FS), is a "marker" for anomalous dominance. The theory predicts lesser left lateralization for language processes, lessened left hemisphere abilities, and enhanced right hemisphere abilities. We assessed language laterality (dichotic consonant vowel task) and performances on spatial and verbal tasks. Subjects were 128 college students. The factors of handedness, sex, FS, and immune disorder history (negative or positive) were perfectly counterbalanced. Left-handers were significantly less lateralized for language and scored lower than right-handers on the spatial tasks. Females scored lower on mental rotation than males, but performed comparably to males on the spatial relations task. The only effect of ID was by way of interaction with FS on both spatial tasks--subjects who were either negative or positive on both FS and ID status factors scored significantly higher than subjects negative for one but positive for the other factor. A speculative explanatory model for this interaction was proposed. The model incorporates the notion that FS and ID factors are comparably correlated, but in opposite directions, with hormonal factors implicated by other research as relevant for spatial ability differences. Finally, no support for the "anomalous dominance" hypothesis predictions was found.