Health psychology: developing biologically plausible models linking the social world and physical health

Psychological science on pregnancy: stress processes, biopsychosocial models, and emerging research issues

Psychological science on pregnancy is advancing rapidly. A major focus concerns stress processes in pregnancy and effects on preterm birth and low birth weight. The current evidence points to pregnancy anxiety as a key risk factor in the etiology of preterm birth, and chronic stress and depression in the etiology of low birth weight. Key mediating processes to which these effects are attributed, that is neuroendocrine, inflammatory, and behavioral mechanisms, are examined briefly and research on coping with stress in pregnancy is examined. Evidence regarding social support and birth weight is also reviewed with attention to research gaps regarding mechanisms, partner relationships, and cultural influences. The neurodevelopmental consequences of prenatal stress are highlighted, and resilience resources among pregnant women are conceptualized. Finally, a multilevel theoretical approach for the study of pregnancy anxiety and preterm birth is presented to stimulate future research.

Transcript origin analysis identifies antigen-presenting cells as primary targets of socially regulated gene expression in leukocytes

To clarify the biological rationale for social regulation of gene expression, this study sought to identify the specific immune cell types that are transcriptionally sensitive to subjective social isolation (loneliness). Using reference distributions for the expression of each human gene in each major leukocyte subtype, we mapped the cellular origin of transcripts found to be differentially expressed in the circulating immune cells from chronically lonely individuals. Loneliness-associated genes derived primarily from plasmacytoid dendritic cells, monocytes, and, to a lesser extent, B lymphocytes. Those dynamics reflected per-cell changes in the expression of inducible genes and related more strongly to the subjective experience of loneliness than to objective social network size. Evolutionarily ancient myeloid antigen-presenting cells appear to have evolved a transcriptional sensitivity to socioenvironmental conditions that may allow them to shift basal gene expression profiles to counter the changing microbial threats associated with hostile vs. affine social conditions.

Depression and hypothalamic-pituitary-adrenal activation: a quantitative summary of four decades of research

OBJECTIVES

To summarize quantitatively the literature comparing hypothalamic-pituitary-adrenal (HPA) axis function between depressed and nondepressed individuals and to describe the important sources of variability in this literature. These sources include methodological differences between studies, as well as demographic or clinical differences between depressed samples.

METHODS

The current study used meta-analytic techniques to compare 671 effect sizes (cortisol, adrenocorticotropic hormone, or corticotropin-releasing hormone) across 361 studies, including 18,454 individuals.

RESULTS

Although depressed individuals tended to display increased cortisol (d = 0.60; 95% confidence interval [CI], 0.54-0.66) and adrenocorticotropic hormone levels (d = 0.28; 95% CI, 0.16-0.41), they did not display elevations in corticotropin-releasing hormone (d = 0.02; 95% CI, -0.47-0.51). The magnitude of the cortisol effect was reduced by almost half (d = 0.33; 95% CI, 0.21-0.45) when analyses were limited to studies that met minimal methodological standards. Gender did not significantly modify any HPA outcome. Studies that included older hospitalized individuals reported significantly greater cortisol differences between depressed and nondepressed groups compared with studies with younger outpatient samples. Important cortisol differences also emerged for atypical, endogenous, melancholic, and psychotic forms of depression.

CONCLUSIONS

The current study suggests that the degree of HPA hyperactivity can vary considerably across patient groups. Results are consistent with HPA hyperactivity as a link between depression and increased risk for conditions, such as diabetes, dementia, coronary heart disease, and osteoporosis. Such a link is strongest among older inpatients who display melancholic or psychotic features of depression.

Academic aptitude as a predictor of headache proneness during college: could headache be an outcome of low test scores?

BACKGROUND

Academic work as well as compensated employment has been found adversely associated with frequent headache; headache remains a costly disorder to the person and to society. However, little is known of factors--other than prior headache complaints--that may predict headache frequency over extended periods of time. Based on previous research, effortful task engagement appears to be a contributing factor to headache onset. This suggests that relatively stable attributes that are likely to affect effort expenditure may predict headache frequency over long intervals.

PURPOSE

The goal of this study was to evaluate the predictability of headache proneness in college-attending students by college aptitude tests administered in high school.

METHODS

Five hundred undergraduate students enrolled in a large public, urban university completed a number of questionnaires. Official admissions records of the college aptitude tests ACT (an acronym for the original test name, the American College Testing), SAT (the Scholastic Aptitude Test), and GPA (grade point average) were obtained and compared to the report of headache frequency.

RESULTS

The ACT test mathematics predicted headache proneness in the hypothesized direction, while the ACT English test provided conflicting data; some evidence of gender differences was suggested.

CONCLUSION

While nearly all research on headache and work effectiveness has considered headache to be a cause of reduced efficiency or productivity, this study suggests that a factor which presumably affects the ease of work completion (e.g., scholastic aptitude) may predict headache, at least in some cases within the "work" environment of academia.

Culture and the Health Benefits of Expressive Writing

Expressive writing, in which individuals put their thoughts and feelings about traumatic events into words, can benefit physical health by fostering insight into the personal meaning of stressful experiences. The authors predicted that expressive writing would neither increase insight nor reduce symptoms of illness among Asian Americans, whose culture deemphasizes the act of verbalization in meaning making. In the present study, European and Asian American participants were randomly assigned to write about either their worst traumas or trivial topics on each of 4 consecutive days. Illness symptoms were assessed immediately before and 1 month after the writing sessions. European Americans who wrote about trauma increased their use of insight words over the four sessions and reported fewer illness symptoms a month later. However, neither effect obtained for Asian Americans. The cultural difference in health outcomes was mediated by European Americans' greater tendency to glean insight from the task.

Work-related stress, inability to relax after work and risk of adult asthma: a population-based cohort study

BACKGROUND

There is an extensive literature linking stressful work conditions to adverse health outcomes. Notwithstanding, the relationship with asthma has not been examined, although various other measures of psychological stress have been associated with asthma. Therefore, we aimed to investigate the relation between work stress and asthma prevalence and incidence.

METHODS

We used data from a population-based cohort study (n = 5114 at baseline in 1992-1995 and n = 4010 at follow-up in 2002/2003). Asthma was measured by self-reports. Two scales that assessed psychologically adverse work conditions were extracted from a list of work-condition items by factor analysis (these scales were termed 'work stress' and 'inability to relax after work'). For each scale, the derived score was employed both as continuous z-score and as categorized variable in analyses. Associations with asthma were estimated by prevalence ratios (PRs) and risk ratios (RRs) using Poisson regression with a log-link function adjusting for demographics, health-related lifestyles, body mass index and family history of asthma. Analyses were restricted to those in employment (n = 3341).

RESULTS

Work stress and inability to relax z-scores were positively associated with asthma prevalence (PR = 1.15, 95%CI = 0.97, 1.36 and PR = 1.43, 95%CI = 1.12, 1.83, respectively). Prospective analyses using z-scores showed that for each 1 standard deviation increase in work stress and inability to relax, the risk of asthma increased by approximately 40% (RR for work stress = 1.46, 95%CI = 1.06, 2.00; RR for inability to relax = 1.39, 95%CI = 1.01, 1.91). Similar patterns of associations were observed in analyses of categorized exposures.

CONCLUSIONS

This is the first study to show a cross-sectional and longitudinal association of work stress with asthma.

Perceived discrimination, psychological distress and health

Racism and discrimination can have significant implications for health, through complex biopsychosocial interactions. Latino groups, and particularly Puerto Ricans, are an understudied population in the United States in terms of the prevalence of discrimination and its relevance to health. Participants in our study were 45- to 75-year-old (N = 1122) Puerto Ricans. The measures were perceived discrimination, depressive symptomatology (CES-D), perceived stress (PSS), self-rated health, medical conditions, blood pressure, smoking and drinking behaviours, demographics. Our findings show that 36.9 per cent of participants had at some time experienced discrimination, with men, those with more years of education, currently employed and with higher incomes being more likely to report it. Experiences of discrimination were associated with increased levels of depressive symptoms and perceived stress. When controlling for covariates, perceived discrimination was predictive of the number of medical conditions, of ever having smoked and having been a drinker, and having higher values of diastolic pressure. Depressive symptoms are a mediator of the effect of perceived discrimination on medical conditions, confirmed by the Sobel test: z = 3.57, p < 0.001. Mediating roles of perceived stress, smoking and drinking behaviours were not confirmed. Increased depressive symptoms might be the main pathway through which perceived discrimination is associated with a greater number of medical diagnoses.

Biosocial Influences on the Family: A Decade Review

The past decade brought a remarkable increase in the number and quality of biosocial studies of family processes. The current review summarizes recent advances in biosocial family research by providing key exemplars of emerging research paradigms. Research in the past decade has substantiated the claim in the previous Decade Review (Booth, Carver, & Granger, 2000) that bidirectional influences between all levels of analysis are paramount. There is an emerging consensus that integrating factors at multiple biological and social levels is highly informative. Because ignoring biological factors often will underestimate mediating or moderating mechanisms, the review provides recommendations for biosocial family research. We also highlight the need for researchers who understand complex family environments to lend their expertise to biosocial studies.

Harsh family climate in early life presages the emergence of a proinflammatory phenotype in adolescence

A growing body of evidence indicates that children reared in harsh families are prone to chronic diseases and premature death later in life. To shed light on the mechanisms potentially underlying this phenomenon, we evaluated the hypothesis that harsh families engender a proinflammatory phenotype in children that is marked by exaggerated cytokine responses to bacterial stimuli and resistance to the anti-inflammatory properties of cortisol. We repeatedly measured psychological stress and inflammatory activity in 135 female adolescents on four occasions over 1.5 years. To the extent that they were reared in harsh families, participants displayed an increasingly proinflammatory phenotype during the follow-up analyses. This phenotype was marked by increasingly pronounced cytokine responses to in vitro bacterial challenge and a progressive desensitization of the glucocorticoid receptor, which hampered cortisol's ability to properly regulate inflammatory responses. If sustained, these tendencies may place children from harsh families on a developmental trajectory toward the chronic diseases of aging.

Influence of Bifidobacterium on the intestinal microflora and corticotropin-releasing factor in rats following chronic psychological stress

AIM: To determine the influence of chronic psychological stress on intestinal microflora and corticotropin-releasing factor (CRF) and to investigate the protective effects of Bifidobacterium on intestinal function in rats.

METHODS: Fifty female Sprague-Dawley rats were randomly and equally divided into five groups: normal group, stress group, Bifidobacterium group, Smecta group, and Bifidobacterium plus Smecta group. All these groups were subjected to either water avoidance stress (WAS) or normal condition for 2 h per day for 7 consecutive days. The in vivo intestinal permeability was evaluated by measuring urinary sucralose and other sugar probes including lactulose and mannitol using capillary column gas chromatography (CCGC). Some representative genera of gut flora in rat feces were counted on selective culture medium plates. The mesenteric lymph nodes (MLN) were removed, homogenized and cultured to determine bacterial translocation. The contents of serum CRF and adrenocorticotrophic hormone (ACTH) were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS: Compared with the normal group, the number of Escherichia coli (7.347 ± 0.277 vs 7.078 ± 0.229, P < 0.05), the 24-h urinary concentration of mannitol (5.097% ± 0.453% vs 4.718% ± 0.399%, P < 0.05), the rate of bacterial translocation to the MLN (40% vs 10%, P < 0.05), and the levels of CRF (300.8 ng/L ± 34.3 ng/L vs 267.0 ng/L ± 32.3 ng/L, P < 0.05) and ACTH (6.79 ng/L ± 0.651 ng/L vs 5.68 ng/L ± 0.799 ng/L, P < 0.05) increased significantly in the stress group. In comparison with the stress group, the number of Escherichia coli (7.044 ± 0.281 vs 7.347 ± 0.277, P < 0.05) and bacteroid (9.075 ± 0.393 vs 9.485 ± 0.306, P < 0.05); the rate of bacterial translocation to the MLN (10% vs 40%, P < 0.05) and ACTH level (5.92 ng/L ± 0.477 ng/L vs 6.79 ng/L ± 0.651 ng/L, P < 0.05) decreased significantly in the Bifidobacterium intervention group.

CONCLUSION: The disturbance of intestinal microflora occurs and CRF increases significantly in rats suffered from chronic psychological stress. Bidifobacterium could alleviate the disturbance of gut microflora caused by chronic psychological stress and partly restore intestinal barrier function.

Depressive symptoms, social support, and risk of adult asthma in a population-based cohort study

OBJECTIVE

To investigate the association between depressive symptoms, social support, and prevalent as well as incident asthma. Depressive symptoms and social support may affect the development of asthma. This relationship could be mediated by health behaviors and/or inflammatory processes. Evidence from prospective cohort studies on depressive symptoms and social support in relation to asthma risk in adults remains sparse.

METHODS

Between 1992 and 1995, a population-based sample of 5114 middle-aged adults completed questionnaires covering depressive symptoms, social support, self-reported asthma, and potential confounders. Among those alive in 2002/2003, 4010 (83%) were followed-up by questionnaires. Associations with prevalent and incident asthma were estimated by prevalence ratios (PR) and risk ratios (RR) along with corresponding 95% confidence intervals (CIs), using Poisson regression. PRs and RRs were adjusted for demographics, family history of asthma, smoking, alcohol consumption, body mass index, and physical exercise.

RESULTS

Cross-sectional analyses indicated that the prevalence of asthma was positively associated with depressive symptoms and inversely related to social support. Prospective analysis suggested a 24% increased risk of asthma with each 1-standard deviation increase in depressive symptoms (RR, 1.24; 95% CI, 1.02, 1.50), whereas the social support z score showed an inverse association with asthma incidence (RR, 0.71; 95% CI, 0.58, 0.88). Analyses with tertiles suggested similar, but nonsignificant, associations. Omitting health-related life-style variables from the multivariable models did not substantially alter these associations.

CONCLUSIONS

Risk of adult asthma was found to increase with depressive symptoms and to decrease with social support. These associations do not seem to be explained by health-related life-style factors.

Social stress and asthma: the role of corticosteroid insensitivity

Psychosocial stress alters susceptibility to infectious and systemic illnesses and may enhance airway inflammation in asthma by modulating immune cell function through neural and hormonal pathways. Stress activates the hypothalamic-pituitary-adrenal axis. Release of endogenous glucocorticoids, as a consequence, may play a prominent role in altering the airway immune homeostasis. Despite substantial corticosteroid and catecholamine plasma levels, chronic psychosocial stress evokes asthma exacerbations. Animal studies suggest that social stress induces corticosteroid insensitivity that in part may be a result of impaired glucocorticoid receptor expression and/or function. Such mechanisms likely promote and amplify airway inflammation in response to infections, allergen, or irritant exposure. This review discusses evidence of an altered corticosteroid responsive state as a consequence of chronic psychosocial stress. Elucidation of the mechanisms of stress-induced impairment of glucocorticoid responsiveness and immune homeostasis may identify novel therapeutic targets that could improve asthma management.

Stress-related modulation of inflammation in experimental models of bowel disease and post-infectious irritable bowel syndrome: role of corticotropin-releasing factor receptors

The interaction between gut inflammatory processes and stress is gaining increasing recognition. Corticotropin-releasing factor (CRF)-receptor activation in the brain is well established as a key signaling pathway initiating the various components of the stress response including in the viscera. In addition, a local CRF signaling system has been recently established in the gut. This review summarize the present knowledge on mechanisms through which both brain and gut CRF receptors modulate intestinal inflammatory processes and its relevance towards increased inflammatory bowel disease (IBD) activity and post-infectious irritable bowel syndrome (IBS) susceptibility induced by stress.

Pearl in the oyster: climate change as a mental health opportunity

Objective: Our world faces potentially catastrophic climate change and we have limited capacity to adapt to rapid or extreme climatic changes. As a result, we can expect significant adverse impacts on health. This includes mental health, a major and growing global concern. It is essential to understand how to respond quickly, effectively and within a manageable budget. The aim of this paper is to propose that the adverse consequences of climate change might offer a subtle but important mental health promotion opportunity which meets these criteria. Conclusions: Climate change will affect mental health directly through increasing exposure to trauma, and indirectly through harming physical health and damaging the physical environment on which economic opportunity depends. Disadvantaged people and communities, especially in rural and remote Australia, will be hardest hit. Seminal work by Alexander Leighton demonstrated how profound disadvantage and associated elevated psychiatric morbidity could be addressed by building community capacity. His methods might be adapted, using the need to address adverse climate change as an opportunity to build social capital. Social capital is associated with a wide range of socioeconomic and health advantages, particularly decreased psychiatric morbidity.

Socioeconomic Status and Health

A robust, linear association between socioeconomic status (SES) and health has been identified across many populations and health outcomes. This relationship is typically monotonic, so that each step down the SES hierarchy brings increased vulnerability to disease and premature mortality. Despite growing attention to health disparities, scientists and policymakers have made little progress toward confronting their causes and implementing effective solutions. Using the reserve capacity model (Gallo & Matthews, 2003) as an organizing framework, the current article examines the contribution of resilient psychosocial resources to socioeconomic disparities in physical health. Findings suggest that deficient psychosocial resources, such as low perceptions of control and social support, may be one of many factors that connect low SES with poor health. Additional research is needed to test these relationships and their underlying mechanisms, to consider interventions to enhance reserve capacity, and to evaluate the efficacy of such efforts in fostering resilience to socioeconomic hardship.

Social regulation of human gene expression

Relationships between genes and social behavior have historically been construed as a one-way street, with genes in control. Recent analyses have challenged this view by discovering broad alterations in the expression of human genes as a function of differing socio-environmental conditions. The emerging field of social genomics has begun to identity the types of genes subject to social regulation, the biological signaling pathways mediating those effects, and the genetic polymorphisms that moderate socio-environmental influences on human gene expression.

Biologic cost of caring for a cancer patient: dysregulation of pro- and anti-inflammatory signaling pathways

PURPOSE

Caring for a family member with cancer is a psychologically demanding experience. However, it remains unclear whether the distress that caregiving provokes also takes a physiologic toll on the body. This study observed familial caregivers of patients with brain cancer for a year after diagnosis and tracked changes in neurohormonal and inflammatory processes.

PATIENTS AND METHODS

Eighteen caregivers (age 50.4 +/- 3.5 years) and 19 controls (age 50.2 +/- 2.6 years) were assessed four times during a year (before and after radiotherapy, as well as 6 weeks and 4 months thereafter). Salivary biomarkers of hypothalamus-pituitary-adrenal axis and sympathetic nervous system (SNS) activity were collected, and blood was drawn for assessment of the systemic inflammatory markers C-reactive protein (CRP) and interleukin-6 (IL-6). Blood was also used to monitor in vitro IL-6 production by endotoxin-stimulated leukocytes and expression of mRNA for pro- and anti-inflammatory signaling molecules.

RESULTS

Caregivers showed marked changes over time in diurnal output of salivary amylase, a marker of SNS activity, whereas secretions in controls were stable during follow-up. Cortisol output was similar in caregivers and controls. During the year, caregivers showed a profound linear increase in systemic inflammation, as indexed by CRP. At the same time, they displayed a linear decline in mRNA for anti-inflammatory signaling molecules and diminished in vitro glucocorticoid sensitivity.

CONCLUSION

These preliminary data show that familial caregivers of patients with cancer experience marked changes in neurohormonal and inflammatory processes in the year after diagnosis. These changes may place them at risk for morbidity and mortality from diseases fostered by excessive inflammation.