Showing papers on "Social stress published in 1997"

Health psychology: What is an unhealthy environment and how does it get under the skin?

Abstract: ▪ Abstract This review explores the role of environments in creating chronic and acute health disorders. A general framework for studying the nesting of social environments and the multiple pathways by which environmental factors may adversely affect health is offered. Treating socioeconomic status (SES) and race as contextual factors, we examine characteristics of the environments of community, work, family, and peer interaction for predictors of positive and adverse health outcomes across the lifespan. We consider chronic stress/allostatic load, mental distress, coping skills and resources, and health habits and behaviors as classes of mechanisms that address how unhealthy environments get “under the skin,” to create health disorders. Across multiple environments, unhealthy environments are those that threaten safety, that undermine the creation of social ties, and that are conflictual, abusive, or violent. A healthy environment, in contrast, provides safety, opportunities for social integration, and th...

Social stress in rats and mice.

Abstract: This paper summarizes some of the highlights of our current social stress research in rodents as it was inspired by the work of Jim Henry. First, it is argued that social defeat can be considered as one of the most severe stressors among a number of laboratory stressful stimuli in terms of neuroendocrine activation. Moreover, the stress response induced by defeat in particular is characterized by a strong sympathetic dominance. Depending on the stress parameter, the stress response induced by a single social defeat may last from hours to days and weeks. As a long term consequence of a single defeat experience, the animal becomes sensitized to subsequent minor stressors. Finally, the importance of individual differences in coping style in relation to stress vulnerability is discussed.

Acquisition of cocaine self-administration after social stress: role of accumbens dopamine

Abstract: Exposure to either aversive or rewarding environmental stimuli increases extracellular dopamine (DA) concentrations in terminal areas of the mesocorticolimbic dopamine system. Furthermore, behavioral reactivity to an environmental stressor has been shown to correlate with latency to initiate self-administration of psychomotor stimulant drugs. The present study examined the behavioral and dopaminergic responses of rats to social defeat stress and compared latencies to initiate cocaine self-administration in defeated and non-defeated rats. In vivo microdialysis was used to examine the effects of social defeat stress on DA concentrations in nucleus accumbens of freely-moving rats. During the experimental session, dialysate and video recording samples were collected from previously-defeated and non-defeated "intruder" rats in consecutive phases, while (1) in the home cage, (2) when placed in the empty, soiled cage of a resident rat which had previously defeated them, and (3) when exposed to threat of defeat by the resident. Immediately following threat of defeat, previously-defeated and non-defeated intruders were given the opportunity to self-administer cocaine IV. When exposed to the olfactory cues of an aggressive resident, extracellular DA levels in nucleus accumbens increased to approximately 135% of baseline in previously defeated rats versus 125% of baseline in non-defeated rats. When exposed to social threat by the resident, DA levels further increased to 145% of baseline in previously defeated rats versus 120% in non-defeated rats. Previously defeated rats acquired cocaine self-administration in approximately half the time of non-defeated rats, consistent with the hypothesis that prior stress exposure may induce a cross-sensitization to the rewarding effects of cocaine. These results are consistent with the idea that exposure to stress may induce changes in central dopaminergic activity, which may render an individual more vulnerable to acquiring psychomotor stimulant self-administration.

Chronic Social Stress, Social Status, and Susceptibility to Upper Respiratory Infections in Nonhuman Primates

Abstract: Objective The objective of the study was to assess the roles of social stress and social status in susceptibility to upper respiratory infection. Method Sixty male cynomolgus monkeys were randomly assigned to stable or unstable social conditions for 15 months. Two markers of social status, social rank and percent of behaviors that were submissive, were assessed at independent observation periods. Endocrine, immune, and behavioral responses were each assessed (at 3-month intervals) during the 9th through 14th months of the study. At the beginning of the 15th month, all animals were exposed to a virus (adenovirus) that causes a common-cold-like illness. The primary outcome was whether or not an animal developed an infection (shed virus) after viral exposure. Results Although the social instability manipulation was associated with increased agonistic behavior as indicated by minor injuries and elevated norepinephrine responses to social reorganizations, the manipulation did not influence the probability of being infected by the virus. However, low social status (as assessed by either marker) was associated with a substantially greater probability of being infected. It was also associated with less body weight, greater elevated cortisol responses to social reorganizations, and less aggressive behavior. However, none of these characteristics could account for the relation between social status and infection. Conclusions Social stress was not associated with susceptibility to infection. However, animals with lower social status were at higher risk than high social status animals.

Social context, coping strategies, and depressive symptoms: an expanded model with cardiac patients.

Abstract: This research broadened and refined a resources model of coping to encompass negative as well as positive aspects of social relationships and examined this expanded conceptualization in a 4-year prospective model with 183 cardiac patients (140 men and 43 women). Social support and social stressors in the family and extrafamily domains contributed significantly to a common social context latent construct. In addition, this conceptualization of social context was significantly related to depressive symptoms 4 years later. Especially important conceptually, coping strategies functioned as a mechanism through which both social support and social stressors related to subsequent depressive symptoms. Moreover, positive and negative aspects of social relationships made essentially unique contributions in predicting subsequent coping efforts.

The social determinants of the decline of life expectancy in Russia and eastern Europe: a lifestyle explanation.

Abstract: This paper examines the social origins of the rise in adult mortality in Russia and selected Eastern European countries. Three explanations for this trend are considered: (1) Soviet health policy, (2) social stress, and (3) health lifestyles. The socialist states were generally characterized by a persistently poor mortality performance as part of a long-term process of deterioration, with particularly negative outcomes for the life expectancy of middle-aged, male manual workers. Soviet-style health policy was ineffective in dealing with the crisis, and stress per se does not seem to be the primary cause of the rise in mortality. Although more research is needed, the suggestion is made that poor health lifestyles--reflected especially in heavy alcohol consumption, and also in smoking, lack of exercise, and high-fat diets--are the major social determinant of the upturn in deaths.

Incidence of arrhythmias and heart rate variability in wild-type rats exposed to social stress

Abstract: Psychological stressors of different natures can induce different shifts of autonomic control on cardiac electrical activity, with either a sympathetic or a parasympathetic prevalence. Arrhythmia occurrence, R-R interval variability, and plasma catecholamine elevations were measured in male wild-type rats exposed to either a social stressor (defeat) or a nonsocial challenge (restraint). Electrocardiograms were telemetrically recorded, and blood samples were withdrawn through jugular vein catheters from normal, freely moving animals. Defeat produced a much higher incidence of arrhythmias (mostly ventricular premature beats), which were mainly observed in the 60-s time periods after attacks. The social challenge also induced a much stronger reduction of average R-R interval, a lower R-R interval variability (as estimated by the time-domain parameters standard deviation of mean R-R interval duration, coefficient of variance, and root mean square of successive differences in R-R interval duration), and higher elevations of venous plasma catecholamines compared with restraint. These autonomic and/or neuroendocrine data indicate that a social stressor such as defeat is characterized by both a higher sympathetic activation and a lower parasympathetic antagonism compared with a nonsocial restraint challenge, which results in a higher risk for ventricular arrhythmias.

Behavioral reactivity to social and nonsocial stimulations: a multivariate analysis of six inbred rat strains.

Abstract: Male rats from six inbred rat strains (Spontaneously Hypertensive Rat, Wistar Kyoto, Brown Norway, Wistar Furth, Fischer 344, and Lewis) have been compared for their behavioral reactivity when placed in several nonsocial (elevated plus-maze, open field) and social (social interaction in aversive and neutral environment, resident–intruder test, chronic social stress) settings. In addition, a factorial analysis was performed to assess how the variables measured in these different tests related to each other. Besides significant strain-related differences in all tests, the factorial analysis showed that, in nonsocial environments, the strains contrasted essentially along two independent behavioral traits, the propensity to approach or avoid an aversive stimulus and general motor activity in novel environments (two indices of emotionality). In the social settings, marked interstrain differences were observed regarding the expression of aggressive behaviors but these differences were not related to the respective levels on the two nonsocial components of reactivity. Furthermore, large genetic differences were observed in variations of body weight induced by a chronic social stressor paradigm. The factorial analysis suggested a lack of relationship between the effect of social stressors on body weight and the measures of emotionality and general activity obtained in the nonsocial tests. Conversely, these variations were influenced by the levels of aggressiveness and sociability. Taken together, these results show (i) that the behavioral variability observed in rats, in social and nonsocial environments, is influenced by genetic factors and (ii) that the behavioral reactivity to social stimulations is a specific feature, dissociable from the levels of the different components of emotionality (approach/avoidance and general activity) as evaluated by the behavioral responses to nonsocial settings.

Environmental effects on fish immune mechanisms

Abstract: Environmental stress factors which influence fish immune (and likely many other physiological) functions can be divided into two broad, but not mutually exclusive, categories, namely those which occur naturally and those which are artificial. Natural environmental stress factors include season, temperature, salinity and photoperiod as well as social stress factors such as crowding and hierarchy. In general, artificial environmental stress factors are man made, and mainly involve pollutants such as acid rain, heavy metals and organic compounds. The available data indicate that regardless of which immune parameters are assessed, both natural and artificial environmental stress factors appear to suppress immune functions. Of the numerous environmental stress factors considered, pollutants, handling/confinement and low temperature are probably the best studied forms in fish. All three forms of stress factors have been shown to suppress components of both the innate (non-specific) and adaptive arms of the immune system. Since immune responses which protect against invading pathogens frequently involve interactions between both the innate and adaptive arms of the immune system, it seems reasonable to conclude that either acute or chronic exposure to stress factors may predispose fish to infectious diseases. Signalling mechanisms responsible for the effects of these various stress factors on immunity in fish are poorly understood, although elevated serum ACTH and cortisol levels appear to be involved in some cases. A better understanding of the mechanism(s) resulting in immunosuppression should facilitate future in vivo manipulations to reduce susceptibility to disease in aquaculture situations.

Stress-Induced Changes in Circadian Rhythms of Body Temperature and Activity in Rats Are not Caused by Pacemaker Changes:

Abstract: Previous work has shown that social stress in rats (i.e., defeat by an aggressive male conspecific) causes a variety of behavioral and physiological changes including alterations in the daily rhythms of body temperature and activity. To study the role of the circadian pacemaker in these stress-induced changes, three experiments were performed, successively addressing pacemaker period, phase, and sensitivity to light. In all experiments, rats were subjected to social stress by placing them in the home cage of a dominant conspecific for 1 h. This was done on 2 consecutive days, between the second and fifth hours of the activity phase. Experimental animals were attacked by the resident and lost the fight as indicated by submissive behavior. Control animals were placed in an unfamiliar but clean and empty cage for 1 h. In Experiment 1, the effects of social stress on the period of the free-running activity rhythm were studied. Rats were individually housed under constant dim red light. Activity was measured with infrared detectors. Social defeat caused a reduction of activity for a number of days, but the period of the free-running rhythm was not affected. In Experiment 2, the authors studied whether social defeat induced acute phase shifts. Body temperature and activity were measured by means of radiotelemetry with intraperitoneally implanted transmitters. After the social interactions, experimental animals were kept under constant dim red light. Social stress caused a profound reduction in the amplitude of the body temperature and activity rhythm, but no significant phase shifts occurred. In Experiment 3, the authors studied whether social defeat affected the circadian pacemaker's sensitivity to light given that the size of light-induced phase shifts is thought to reflect pacemaker amplitude. Again, body temperature and activity were measured by means of telemetry. After double social defeat, animals were kept under continuous dim red light. One day after the second conflict, animals were subjected to a single 1-h light pulse (300 lux) at circadian time 14. The light pulse induced a phase delay of the body temperature rhythm, but there were no significant differences between the stress and control groups. The data indicate that stress-induced changes in activity and temperature rhythm, as well as behavioral and physiological changes found in earlier experiments, are not caused by changes in the circadian pacemaker. More generally, the data support the notion that overt rhythms are not always a reliable indication of pacemaker function.

The integrative neurobiology of affiliation. Introduction.

Abstract: The research presented at this conference, including a series of excellent posters from junior investigators, documents the pervasive importance of affiliation and other social behaviors. Affiliative behaviors interact with, but are distinct from reproductive and aggressive behaviors. Patterns of social behaviors tend to be more species-typical than the behaviors associated with reproduction or aggression. However, neural circuits necessary for approach or avoidance also are necessary for the expression of various types of affiliative behavior such as maternal behavior or pair-bond formation. Furthermore, candidate neurochemical systems have been identified that contribute to various types of affiliative behavior. For example, studies revealing new behavioral functions for steroid hormones of the adrenal axis, such as corticosterone, and neuropeptides, including the endorphins, oxytocin and vasopressin, extend our general knowledge of neurobiology; they may also lead to studies that expand our understanding of social behavior and the connections to systems that regulate emotions. The work represented in this volume also has important implications for the study of serious neuropsychiatric disorders. For example, episodes of certain of these disorders can be induced by social stressors; in other disorders, a marked decrease in affiliative behaviors is a prominent feature of the patients' difficulties. Furthermore, abnormalities in animal systems implicated in the neurobiology of affiliation (oxytocin, vasopressin, and the hypothalamic-pituitary-adrenal system) have also been documented for major depression in humans. Animal models, such as those described at this conference, offer evolutionary perspectives, from which it is possible to extract general principles. At the same time, our understanding of the mechanistic and neurobiological substrates of both constructive and destructive social behaviors is increasing. At the conference, the evolutionary and mechanistic perspectives converged on the theme that studies of affiliative behaviors cannot be fully interpreted in isolation from other social behaviors; neither can they effectively be isolated from the biological and social contexts that shape their expression. Advances in this research area seem dependent on integrating experimental research across levels of analysis. Although this task is challenging, we are confident that an awareness of integrative principles can lead to new and important research opportunities.

Social stress, depression, and brain dopamine in female cynomolgus monkeys.

Abstract: Socially subordinate adult female cynomolgus monkeys are hypercortisolemic, the targets of aggression, fearful, vigilant, receive little positive affiliative contact, exhibit pathological behaviors indicating anxiety, and are disengaged in the social events around them. Subordinates also have altered dopaminergic activity that may be due to decreased D2 receptor binding. Dopaminergic activity indices were more closely associated with affiliative than agonistic behaviors.

The Intergenerational Costs of Parental Social Stressors: Academic and Social Difficulties in Early Adolescence for Children of Young Mothers*

Abstract: Social stressors embedded in parents' occupational and family roles have been shown to have effects on family interaction and the cognitive and emotional development of young children. Here we consider whether these patterns also hold for children in early adolescence. We study 1,158 10 to 14-year-old children born to the early childbearers among the female respondents of the National Longitudinal Survey of Youth cohort. We find that both poor quality of parental employment and low quality of mothers' relationships with their partners have adverse effects on the cognitive stimulation and maternal warmth children receive; living in informal unions is also associated with poorer parent-child interaction. These family interaction patterns in turn both buffer the effects of stressful family conditions and shape academic and behavior outcomes directly. Some work and family conditions interact in their effects : In particular, single mothering has less adverse effects on cognitive stimulation and behavior problems when mothers are employed in occupations providing higher complexity. The effects of current conditions are diminished but seldom eliminated when we control for possible selection effects by using data from earlier waves to control for earlier levels of child problems. These findings suggest that current parental social stressors continue to have consequences for both academic and behavioral outcomes during early adolescence.

Stress appraisal and social support of Chinese mothers of adult children with mental retardation

Abstract: Thirty Chinese mothers of adult children with moderate to severe mental retardation were interviewed to explore the source and nature of their stress and social support Results revealed child-related and parent-related stress specific to these mothers The most common stressors were future planning and behavioral problems of the target offspring Mothers received tangible, emotional, and informational support mainly from family members and training center staff Some evidence was also found for the optimal-matching model of stress appraisal and social support Regardless of the duration of stress, all forms of support were perceived as equally useful for uncontrollable stress, whereas tangible support was regarded as more useful than informational support for controllable stress

Appraisal and coping strategies in stressful situations: A comparison of individuals who binge eat and controls.

Abstract: Objective The objective of this study was to investigate whether individuals who engage in binge eating appraise and cope with stressful situations in a different manner than people who do not regularly binge eat. Method: Female undergraduates participated in a two-part study. The laboratory portion of the study involved participation in two tasks: an interpersonal stressor and an academic stressor. In the second portion of the study, participants completed a daily stress inventory for 1 week. Results: Individuals in the binge group appraised both the laboratory and natural environment stressors as more stressful than did the controls. Differences were evident in the amount an type of coping strategies used between eating groups. The binge group reported using more positive coping strategies and more catastrophizing in both settings. Discussion: Together, the results suggest that appraisal and coping or stress management components may be useful in treatment packages for individuals who binge eat. © 1997 John Wiley & Sons, Inc.

Stress and illness in adolescence: issues of race and gender.

Abstract: There is an abundance of information on the association between stressful life events and illness within the adult population. In contrast, research on this relationship among adolescents is limited. This study evaluated the role of individual differences (gender and race) on the stress-illness relationship within the adolescent population. Participants were 119 adolescents (54 females and 65 males), recruited from two public high schools located in the southeast, who were administered four questionnaires designed to measure levels of stress, anxiety, and illness. Overall, correlational analysis revealed that stress and anxiety were positively correlated with reported illness. However, racial and gender differences did emerge. Although no gender differences were found with regard to the experience of stress, African-American athletes reported a higher frequency of stressful life events than did their Euro-American counterparts. Further, African-American adolescents reported a lower frequency of illness than did the Euro-Americans. Females reported more illnesses than did males. Possible explanations for individual differences in reported stress and illness are discussed.

Depression in the Caregiving Mothers of Adult Schizophrenics: A Test of the Resource Deterioration Model

Abstract: The predictive validity of the resource deterioration model was tested with a sample of 100 Black, elderly, low-income, unmarried, caregiving mothers of adult schizophrenic sons and/or daughters. Stressors consisted of three social variables (burden of care, economic strain, undesirable life events) and one physical variable (poor physical health). Stress mediators consisted of coping and social support resources; the outcome variable was defined as depression. The results indicated support for the resource deterioration model with regard to a physical stressor and coping resources, but not for social stressors and social support resources.

Ethnicity, gender and social stress among three groups of elderly Hispanics.

Abstract: This study examines ethnic and gender differences in social stress amongthree groups of elderly Hispanics: Mexican Americans (n = 773), CubanAmericans (n = 714), and Puerto Ricans (n = 368). Findings from thecrosstabulation analysis between stress and ethnic groups reveal that theelderly Cuban Americans appear to experience less caregiving, family,anxiety, and social dependence stress than their Mexican Americans andPuerto Rican American counterparts. Findings from the crosstabulationanalysis between stress and gender reveal that elderly Hispanic womenwere more likely to experience family, anxiety, social isolation, and socialdependence stress. The logistic regression analyses reveal that ethnicdifferences in family stress, and anxiety and gender differences incaregiving stress and social isolation stress were confounded bydifferences in sociodemographic and health variables. Further sub-groupanalyses of ethnic and gender differences provide a more in-depthunderstanding of social dependency stress and anxiety. Implications forhuman services and research are discussed.

Genetic influences on the responses to psychosocial challenges in rats.

Abstract: "Psychosocial stress can induce chronic hypertension in normotensive strains of rats" (Henry et al. 1993). This effect is however variable among different strains. Factor analysis of the relationships between temperamental dimensions measured in social and nonsocial settings shows that sensitivity to chronic social stress loads on a "social reactivity" factor different from spontaneous aggressive tendencies. Furthermore an "end-organ" sensitivity of the cardiovascular system also seems to be necessary to explain individual vulnerability to psychosocial stress-induced hypertension. These psychological and pathophysiological characteristics combine with situational components that are not yet fully defined. The advent of telemetry techniques to monitor heart rate and blood pressure continuously without any disturbance to the animals should facilitate the analytical approach of this complex, multifactorial condition.