Asymmetry in children's salivary cortisol and alpha-amylase in the context of marital conflict: links to children's emotional security and adjustment

Patterns of stress-related change in salivary alpha-amylase and cortisol among young children: Associations with maternal psychosocial risk factors

Our understanding of associations between family-level risk factors and children's stress physiology is largely derived from studies that apply "mean-based" rather than "person-level" approaches. In this study, we employed group-based trajectory modeling, a person-centered approach, to identify children with similar patterns of stress-related sympathetic nervous system (SNS) and hypothalamic-pituitary-adrenal (HPA) axis activation, and explored associations between these patterns and maternal psychosocial risk. Participants were five-year-old children (N=147; 52 % female; 62 % Black/African American) and their mothers. Children's saliva was sampled four times during a series of emotional stressor tasks and later assayed for sAA and cortisol, indexing SNS and HPA activity, respectively. Mothers reported their depressive and anxiety symptoms, parenting stress, financial stress, and income. Results revealed two task-related patterns of change for sAA (Low-Stable vs. High-Increasing) and cortisol (Low-Stable vs. High-Decreasing) concentrations. Children from families with lower income were more likely to exhibit the High-Increasing SNS pattern, [OR=0.78, 95 % CI (0.64, 0.95)], and children of mothers reporting more anxiety symptoms [OR=1.06, 95 % CI (1.00, 1.12)] and more parenting stress [OR=1.04, 95 % CI (1.00, 1.07)] were more likely to show the High-Decreasing HPA pattern. Implications of this person-centered approach and findings for advancing our understanding of associations between family-level risk factors and children's stress physiology are discussed.

Restoration of typical HPA-SAM co-activation following psychosocial intervention among preadolescent youth living in poverty

Despite the added value of multisystem (relative to traditional single-system) approaches for characterizing biological processes linked to risk for psychopathology (e.g., neuroendocrine stress responsivity; Buss et al., 2019; Quas et al., 2014), no study to date has evaluated whether multisystem processes may serve as viable biological targets of intervention. Utilizing a multiple-levels-of-analysis approach (Cicchetti & Dawson, 2002), this person-centered study examined whether stress-adapted patterns of hypothalamus-pituitary-adrenal (HPA) axis and sympathetic-adrenomedullary (SAM) system co-activation were amenable to change following the Building a Strong Identity and Coping Skills intervention (BaSICS; Wadsworth et al., 2022). Preadolescents exposed to concentrated poverty (n = 112, M age = 11.78 years, 57.1% female, 54% assigned to intervention; 40% Hispanic, 63% Black, 20% White) completed questionnaires and the Trier Social Stress Test at both pre- and posttest. Multitrajectory modeling of cortisol and alpha-amylase levels identified four pretest and posttest HPA-SAM co-activation profiles. At pretest, youth exhibiting Asymmetric Nos. 1 & 2 HPA-SAM co-activation reported greater maladjustment relative to youth with Symmetric Nos. 1 & 2 co-activation. Youth exhibiting Asymmetric No. 1 co-activation at pretest were more likely to exhibit Symmetric No. 1 co-activation following BaSICS relative to control. Findings highlight the potential of BaSICS to restore neuroendocrine stress response function in impoverished youth, pointing to HPA-SAM co-activation as a potential biological target of preventive intervention in this population.

Cross-sectional analysis reveals COVID-19 pandemic community lockdown was linked to dysregulated cortisol and salivary alpha amylase in children

The COVID-19 pandemic altered everyday life starting in March 2020. These alterations extended to the lives of children as their normal routines were disrupted by community lockdowns, online learning, limited in-person social contact, increased screen time, and reduced physical activity. Considerable research has investigated the physical health impact of COVID-19 infection, but far fewer studies have investigated the physiological impact of stressful pandemic-related changes to daily life, especially in children. The purpose of this study was to leverage an ongoing clinical trial to investigate physiological consequences associated with chronic stress of pandemic community lockdown on children. As a part of the clinical trial, children provided saliva samples. Saliva samples were analyzed for cortisol and salivary alpha amylase (sAA) content. This secondary cross-sectional analysis included 94 preadolescent children located within the Greater Boston, Massachusetts community. Children participated in the study either before, during, or following the pandemic community lockdown to form three groups for comparison. In response to chronic stress caused by the pandemic community lockdown, participants demonstrated dysregulation of fast-acting catecholamine response of the locus-coeruleus-norepinephrine system and slower-acting glucocorticoid response, resulting in an asymmetrical relationship of hypocortisolism (M = 0.78 ± 0.19 μg/mL, p < 0.001) paired with higher sAA (M = 12.73 ± 4.06 U/mL, p = 0.01). Results suggest that the abrupt COVID-19 disruption to daily life, including the stressful experience of community lockdown, had physiological effects on typically developing children. Further research is required to investigate mental health outcomes of children following the chronic stress of the pandemic community lockdown.

Psychologically aggressive parenting and later aggression: Salivary alpha-amylase reactivity and sex as moderators

Psychologically aggressive parenting (PAP) exposure negatively affects children's development of aggression. Nevertheless, not all children exposed to PAP display aggressive behaviors. Sympathetic nervous system (SNS) activity may influence the impact of early adversity on aggression. This study examines whether SNS reactivity and sex moderate the link between psychologically aggressive parenting (PAP) during childhood and later aggression. Emerging adults (N = 182, mean age = 19.03 years, 53 % female) retrospectively reported on their childhood PAP and current aggression. Salivary alpha-amylase (sAA) collected from a social stress task indexed SNS reactivity to stress. Childhood PAP was associated with emerging adulthood anger, hostility, physical, and verbal aggression. Moreover, males were more likely to exhibit anger, verbal, and physical aggression and had higher levels of sAA reactivity than females. A significant three-way interaction between childhood PAP, sAA reactivity, and sex accounted for participants' current verbal aggression. The link between childhood PAP and later verbal aggression was stronger for males at higher levels of sAA reactivity. Females with higher levels of sAA reactivity displayed lower levels of verbal aggression regardless of PAP exposure. Males and females with lower levels of sAA reactivity were at elevated risk for verbal aggression regardless of PAP exposure. Moreover, we found a significant two-way interaction between PAP and sex on anger, such that higher levels of PAP exposure were associated with more anger among males, but not females. These findings highlight the importance of examining interactions between biological and environmental factors and sex in accounting for later aggression.

Longitudinal Relationships Between Interparental Conflict and Adolescent Depression: Moderating Effects of School Connectedness

The present study examined the association between interparental conflict and adolescent depression, and explored the moderating role of school connectedness in this association, in a Chinese context. Data were analyzed from 867 Chinese adolescents who completed the survey at 2 time points. Cross-lagged analyses indicated that interparental conflict in 7th grade adolescents significantly predicted depression in 8th grade, but adolescent depression in 7th grade was not a significant predictor of interparental conflict in 8th grade. In addition, there was a significant negative moderating effect of school connectedness, as high levels of school connectedness reduced the negative effect of interparental conflict on adolescent depression. Thus, the association between interparental conflict and adolescent depression has a unidirectional prediction. School connectedness can relieve the adverse effects of interparental conflict on adolescent depression.

HPA-SAM co-activation among racially diverse, economically disadvantaged early adolescents: Secondary analysis with a preliminary test of a multisystem, person-centered approach

Investigating the co-activation of hypothalamic-pituitary-adrenal (HPA) and sympathetic-adrenomedullary (SAM) responses to acute stress can provide insight into how risk might become biologically embedded during early adolescence and improve understanding of what distinguishes physiological dysregulation from normative/expected physiological responses to stress. Evidence has thus far been mixed as to whether symmetric or asymmetric co-activation patterns are associated with higher exposure to chronic stress and poorer mental health outcomes during adolescence. This study expands on a prior multisystem, person-centered analysis of lower-risk, racially homogenous youth by focusing on HPA-SAM co-activation patterns in a higher-risk, racially diverse sample of early adolescents from low-income families (N = 119, Mage=11.79 years, 55.5% female, 52.7% mono-racial Black). The present study was conducted by performing secondary analysis of data from the baseline assessment of an intervention efficacy trial. Participants and caregivers completed questionnaires; youth also completed the Trier Social Stress Test-Modified (TSST-M) and provided six saliva samples. Multitrajectory modeling (MTM) of salivary cortisol and alpha-amylase levels identified four HPA-SAM co-activation profiles. In accordance with the asymmetric-risk model, youth exhibiting Low HPA-High SAM (n = 46) and High HPA-Low SAM (n = 28) profiles experienced more stressful life events, posttraumatic stress, and emotional and behavioral problems relative to Low HPA-Low SAM (n = 30) and High HPA-High SAM (n = 15) youth. Findings highlight potential differences in biological embedding of risk during early adolescence based on individuals' exposure to chronic stress and illustrate the utility of multisystem and person-centered approaches in understanding how risk might get "underneath the skin" across systems.

Childhood violence exposure and externalizing behaviors: A systematic review of the role of physiological biomarkers

Childhood exposure to violence has been consistently linked to externalizing behaviors like delinquency and aggression. Growing evidence indicates that physiological biomarkers from the parasympathetic and sympathetic nervous systems (PNS and SNS) and hypothalamic-pituitary-adrenal (HPA) axis may moderate or mediate the relation between childhood violence exposure and externalizing behaviors. We conducted a systematic review to synthesize recent findings on physiological biomarkers as mediators and/or moderators of this association across the life course, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Our search yielded 3878 articles, of which 44 met inclusion criteria (describing a total of 46 independent studies). We found consistent evidence for blunted HPA-axis reactivity as a mediator of the relation between childhood violence exposure and subsequent externalizing behaviors, and for non-reciprocal PNS/SNS activation as moderators exacerbating this relation. However, the results of the majority of included studies that demonstrated significant moderating effects of physiological biomarkers varied by participant sex, type of childhood violence exposure, and type of stimuli used to induce physiological reactivity. The observed mixed findings are consistent with some theories that emphasize that both high and low stress reactivity can be adaptive depending on one's early environment. These findings highlight the need for systematic explorations of heterogeneity, theory-driven research questions, and longitudinal studies that span multiple developmental periods and multiple biological systems. Clinical implications include the need to assess physiological biomarkers in treatment and intervention studies and the potential to target interventions based on both autonomic functioning and environmental contexts.

Associations between multisystem stress reactivity and peer nominated aggression in early childhood vary by sex

There is emerging evidence that the development of problematic aggression in childhood may be associated with specific physiological stress response patterns, with both biological overactivation and underactivation implicated. This study tested associations between sex-specific patterns of stress responses across the sympathetic nervous system (SNS) and hypothalamic-pituitary-adrenal (HPA) axis and peer nominations of aggression among 271 kindergarten children (Mean age = 5.32 years; 52% Female; 44% White). Upon entry to kindergarten, children participated in a multidomain standardized stress paradigm. Changes in pre-ejection period (PEP) and salivary cortisol were assessed. On a separate day, children provided peer ratings of physical and relational aggression in a standardized interview. As expected, there was a significant three-way interaction between PEP, cortisol reactivity, and sex, but only for physical aggression. Among boys, cortisol reactivity was positively associated with physical aggression only for those with higher SNS reactivity. Findings suggest that for boys, asymmetrical and symmetrical HPA/SNS reactivity may be associated with lower and higher risk for peer-directed physical aggression, respectively. Understanding the complex associations between multisystem physiology, child sex and peer-directed aggression in early childhood may offer insight into individual differences underlying the emergence of behavioral dysregulation in early peer contexts.

Neuroendocrine coordination and youth behavior problems: A review of studies assessing sympathetic nervous system and hypothalamic-pituitary adrenal axis activity using salivary alpha amylase and salivary cortisol

Externalizing and internalizing behavior problems can have deleterious psychosocial consequences for youth. Both sympathetic nervous system (SNS) and hypothalamic-pituitary adrenal (HPA) axis activity and reactivity may contribute to behavior problems but have largely been studied separately, with inconsistent findings. Because the SNS and HPA axis interact to carry out physiological processes (e.g., responding to stressors), considering SNS and HPA axis activity jointly may elucidate disparate findings. This review discusses studies that simultaneously assessed SNS and HPA axis (re)activity and youth behavior problems using measures of salivary alpha amylase (sAA) and salivary cortisol. Multiple patterns of SNS and HPA axis coordination were associated with problem behaviors, especially when considering individual differences and youth's psychosocial context. Importantly, many study findings may be artifacts of widespread methodological differences. The reviewed studies lay the foundation for future research on neuroendocrine coordination as a contributing factor to youth problem behaviors and some recommendations for future research are discussed.

Child depressive symptoms: Associations with salivary cortisol and alpha amylase in two distinct challenges

Child depression has been inconsistency linked to cortisol and salivary alpha-amylase (sAA) reactivity. This study assessed three factors that contribute to inconsistencies: 1) the differential effectiveness of laboratory challenges to elicit cortisol and sAA; 2) the impact of cortisol-sAA coordination; and 3) variation in parent versus child ratings of depression. A community sample of 52 children participated in the Trier Social Stress Test-Child Version (TSST-C) and a competition challenge. Saliva was collected and assayed for cortisol and sAA. Analyses were conducted using multilevel modeling. Child-reported depressive symptoms were associated with a declining cortisol trajectory in the TSST-C. Mother-reported depressive symptoms were associated with higher baseline sAA in the TSST-C and the competition challenge. Further, child-reported depressive symptoms were associated with cortisol-sAA coordination in the competition challenge. Findings underscore the nature of the challenge and the behavioral informant as impacting associations between child depressive symptoms and cortisol and sAA secretion.

Co-activation of SAM and HPA responses to acute stress: A review of the literature and test of differential associations with preadolescents' internalizing and externalizing

Understanding co-activation patterns of the hypothalamic-pituitary-adrenal axis (HPA) and sympathetic adrenal medullary (SAM) during early adolescence may illuminate risk for development of internalizing and externalizing problems. The present study advances empirical work on the topic by examining SAM-HPA co-activation during both the reactivity and recovery phases of the stress response following acute stress exposure. Fourth and fifth grade boys and girls (N = 149) provided cortisol and alpha-amylase via saliva at seven times throughout a 95-min assessment in which they were administered the modified Trier Social Stress Test. Parents reported on adolescents' life stress, pubertal development, medication use, and externalizing problems. Adolescents reported their own internalizing symptoms. Multiple linear regressions tested both direct and interactive effects of SAM and HPA reactivity and recovery on internalizing and externalizing problems. Results from these analyses showed that whereas SAM and HPA reactivity interacted to predict internalizing symptoms, it was their interaction during the recovery phase that predicted externalizing. Concurrent high SAM and HPA reactivity scores predicted high levels of internalizing and concurrently low SAM and HPA recovery scores predicted high levels of externalizing. Implications of the findings for further study and clinical application are discussed.

Female primary and secondary psychopathic variants show distinct endocrine and psychophysiological profiles

Research with predominantly male samples supports primary and secondary developmental pathways to psychopathy that are phenotypically indistinguishable on aggressive and antisocial behavior. The aim of this study was to examine whether female variants of psychopathy show divergent endocrine (i.e., cortisol, dehydroepiandrosterone [DHEA], testosterone, and their ratios) and psychophysiological (i.e., heart rate variability [HRV]) reactivity to social provocation. We also tested whether variants differed on reactive aggression when performing a competitive reaction time task against the fictitious participant who previously insulted them. Latent profile analyses on 101 undergraduate women oversampled for high psychopathic traits identified a high-anxious, maltreated secondary variant (n=64) and a low-anxious primary variant (n=37). Although variants did not differ on aggression, secondary variants showed higher cortisol, testosterone, cortisol-to-DHEA ratios, and HRV following social provocation relative to primary variants. Findings suggest that the neurobiological mechanisms underpinning aggression in psychopathy may differ between women on primary versus secondary developmental pathways.

Stress physiology and memory for emotional information: Moderation by individual differences in pubertal hormones

In contrast to a large body of work concerning the effects of physiological stress reactivity on children's socioemotional functioning, far less attention has been devoted to understanding the effects of such reactivity on cognitive, including mnemonic, functioning. How well children learn and remember information under stress has implications for a range of educational, clinical, and legal outcomes. We evaluated 8-14 year olds' (N = 94, 50 female) memory for negative, neutral, and positive images. Youth had seen the images a week previously as a part of a laboratory stress task. At encoding and retrieval, and in between, youth provided saliva samples that were later assayed for cortisol, salivary α amylase (sAA), testosterone, and dehydroepiandrosterone (DHEA). Overall, higher cortisol reactivity to the lab task predicted enhanced memory for emotional but not neutral images. However, cortisol further interacted with pubertal hormones (testosterone and DHEA) to predict memory. Among girls with lower pubertal hormone levels, greater cortisol reactivity was associated with enhanced memory for negative information, whereas among boys with higher pubertal hormone levels, cortisol reactivity was associated with enhanced memory for positive information. sAA, was unrelated to memory. Overall, our findings reveal that individual differences in hormone levels associated with pubertal development have implications for our understanding of how stress-responsive biological systems directly and interactively influence cognitive outcomes. (PsycINFO Database Record

Interparental conflict and child HPA-axis responses to acute stress: Insights using intensive repeated measures

Interparental conflict is a common source of psychosocial stress in the lives of children. The purpose of this study was to examine the association between recent interparental conflict and one component of the physiological stress response system, the hypothalamic-pituitary-adrenal (HPA)-axis. Parents of 42 children (ages 8-13 years) completed daily diaries of interparental conflict for 8 weeks. At the end of the 8 weeks, youth participated in the Trier Social Stress Test for Children (TSST-C) while providing 2 pre- and 4 poststress salivary cortisol samples. Youth whose fathers reported a pattern of increasing interparental conflict over the past 8 weeks demonstrated an exaggerated HPA-axis response to acute stress. Mother-reported interparental conflict was not associated with children's HPA-axis responses without accounting for fathers' reports. When accounting for fathers' reports, the offspring of mothers reporting higher average daily interparental conflict demonstrated an attenuated HPA-axis response to the stressor. By estimating both average exposure and recent patterns of change in exposure to conflict, we address the circumstances that may prompt attenuation versus sensitization of the HPA-axis in the context of interparental conflict. We conclude that the HPA-axis is sensitive to proximal increases in interparental conflict which may be one pathway through which stress affects health across development, and that incorporating father's reports is important to understanding the role of the family environment in stress responses. This study further demonstrates the value of using intensive repeated measures and multiple reporters to characterize children's psychosocial environment. (PsycINFO Database Record

Animal Models of the Impact of Social Stress on Cocaine Use Disorders

Cocaine use disorders are strongly influenced by the social conditions prior, during, and after exposure to cocaine. In this chapter, we discuss how social factors such as early life stress, social rank stress, and environmental stress impact vulnerability and resilience to cocaine. The discussion of each animal model begins with a brief review of examples from the human literature, which provide the psychosocial background these models attempt to capture. We then discuss preclinical findings from use of each model, with emphasis on how social factors influence cocaine-related behaviors and how sex and age influence the behaviors and neurobiology. Models discussed include (1) early life social stress, such as maternal separation and neonatal isolation, (2) social defeat stress, (3) social hierarchies, and (4) social isolation and environmental enrichment. The cocaine-related behaviors reviewed for each of these animal models include cocaine-induced conditioned place preference, behavioral sensitization, and self-administration. Together, our review suggests that the degree of psychosocial stress experienced yields robust effects on cocaine-related behaviors and neurobiology, and these preclinical findings have translational impact for the future of cocaine use disorder treatment.

Chronic Stress in Children and Adolescents: A Review of Biomarkers for Use in Pediatric Research

PROBLEM

Incorporating biomarkers of chronic stress into pediatric research studies may help to explicate the links between exposure to adversity and lifelong health, but there are currently very few parameters to guide nurse researchers in choosing appropriate biomarkers of chronic stress for use in research with children and adolescents.

METHODS

Biomarkers of chronic stress are described, including primary mediators (glucocorticoids, catecholamines, and cytokines) and secondary outcomes (neurologic, immune, metabolic, cardiovascular, respiratory, and anthropometric) of the chronic stress response.

RESULTS

Evidence of the use of each biomarker in pediatric research studies is reviewed. Recommendations for pediatric researchers, including selection of appropriate biomarkers, measurement considerations, potential moderators, and future directions for research, are presented.

DISCUSSION

A wide range of biomarkers is available for use in research studies with children. While primary mediators of chronic stress have been frequently measured in studies of children, measurement of secondary outcomes, particularly immune and metabolic biomarkers, has been limited. With thoughtful and theoretically based approaches to selection and measurement, these biomarkers present an important opportunity to further explore the physiologic pathways linking exposure to chronic stress with later health and disease.

CONCLUSION

The incorporation of chronic stress biomarkers into pediatric research studies may provide valuable insight into the mechanisms through which stressful environments "get under the skin" and ultimately inform efforts to promote health and reduce inequities among children exposed to adversity.

The role of stress response in the association between autonomy and adjustment in adolescents

Developing autonomy is an important developmental task that has implications for adolescent adjustment and may be impacted by adolescents' response to stress. This study examined whether stress reactivity (i.e., cortisol and heart rate reactivity) to a parent-adolescent conflict interaction moderates the effect of autonomy on adjustment assessed one year later in 100 adolescents (M age = 15.09; 68% girls). Multiple group models suggested that youth who evidenced higher stress reactivity when compared to those with lower stress reactivity were more likely to report decreased externalizing problems and internalizing problems when their parents granted more autonomy. In contrast, youth who evidenced higher stress reactivity who experienced undermining of autonomy were more likely to report increased externalizing and internalizing problems than youth who evidenced lower stress reactivity. Results support biological sensitivity to context theory and highlight the importance of considering individual differences in the effect of developmental milestones on adolescents' adjustment.

Annual Research Review: Early adversity, the hypothalamic-pituitary-adrenocortical axis, and child psychopathology

BACKGROUND

Research on early adversity, stress biology, and child development has grown exponentially in recent years.

FINDINGS

We review the current evidence for the hypothalamic-pituitary-adrenocortical (HPA) axis as a stress-mediating mechanism between various forms of childhood adversity and psychopathology. We begin with a review of the neurobiology of the axis and evidence for relations between early adversity-HPA axis activity and HPA axis activity-psychopathology, as well as discuss the role of regulatory mechanisms and sensitive periods in development.

CONCLUSIONS

We call attention to critical gaps in the literature to highlight next steps in this research including focus on developmental timing, sex differences, stress buffering, and epigenetic regulation. A better understanding of individual differences in the adversity-HPA axis-psychopathology associations will require continued work addressing how multiple biological and behavioral systems work in concert to shape development.

Person-centered examination of salivary cortisol and alpha-amylase responses to psychosocial stress: Links to preadolescent behavioral functioning and coping

This study adopted a person-centered approach to identify preadolescent salivary cortisol (sC) and alpha-amylase (sAA) co-activation response patterns and examine links to behavioral functioning and coping. Children (N = 151, 51.7% male) were exposed to the Trier Social Stress Test (TSST) and one of two randomly-assigned, post-TSST coping conditions: distraction or avoidance. Multi-trajectory modeling yielded four child subgroups. Child internalizing and externalizing positively predicted High sC-High sAA relative to Low sC-Low sAA and Low sC-High sAA relative to High sC-Low sAA subgroup membership, respectively. Low sC-Low sAA children demonstrated more efficient sC recovery when primed with distraction and more protracted sC recovery when primed with avoidance. For High sC-High sAA, internalizing children, the opposite was true. Findings illustrate adjustment-linked variability in preadolescent sC-sAA co-activation response patterns that further articulates for whom effortful coping works to effectively manage stressor-induced neuroendocrine activation.

Effects of early life adversity on cortisol/salivary alpha-amylase symmetry in free-ranging juvenile rhesus macaques

Early life adversity (ELA) affects physiological and behavioral development. One key component is the relationship between the developing Hypothalamic-Pituitary-Adrenal (HPA) axis and the Sympathetic Nervous System (SNS). Recent studies suggest a relationship between early life adversity and asymmetry in cortisol (a measure of HPA activation) and salivary alpha-amylase (sAA: a correlate of SNS activation) responses to stress among human children, but to our knowledge there have been no comparable studies in nonhumans. Here, we investigate the responses of these two analytes in "low stress" and "high stress" situations in free-ranging juvenile rhesus macaques (Macaca mulatta) on Cayo Santiago, Puerto Rico. Behavioral data on maternal maltreatment were collected during the first 3months of life to determine individual rates of ELA, and saliva samples were collected from subjects noninvasively during juvenility. Irrespective of ELA, salivary alpha-amylase levels were lower in low stress situations and higher in high stress situations. For cortisol however, high ELA subjects exhibited higher low stress concentrations and blunted acute responses during high stress situations compared to moderate and low ELA subjects. Cortisol and sAA values were positively correlated among low ELA subjects, suggesting symmetry, but were uncorrelated or negatively correlated among moderate and high ELA subjects, suggesting asymmetry in these individuals. These findings indicate dysregulation of the stress response among juveniles maltreated during infancy: specifically, attenuated cortisol reactivity coupled with typical sAA reactivity characterize the stress response profiles of juveniles exposed to higher rates of ELA during the first 3months of life.

Field endocrinology of nonhuman primates: past, present, and future

In the past few decades, research on nonhuman primate endocrinology has moved from the lab to the field, leading to a huge increase in both the breadth and depth of primate field studies. Here, I discuss the past, present, and future of primate field endocrinology. I review the history of the field, and go on to discuss methodological developments and the issues that they sometimes entail. Next, I consider ways in which we might conceptualize the role of hormones, and focus on the need to distinguish proximate from ultimate levels of explanation. Current potentially problematic issues in the field include: 1) an inability to obtain noninvasive measurements of Central Nervous System (CNS) rather than peripheral hormone concentrations; 2) research questions that become stuck (e.g., questions regarding sexual swelling expression mechanisms); 3) data dredging and post-hoc linking of hormones to any plausible variable, leading to a lack of clarity on their role in animal ecology and behavior. I finish by discussing several unanswered questions that might benefit from further research. These are how we might: 1) best obtain measurements for CNS hormone concentrations non-invasively; 2) measure hormone receptor expression alongside hormone concentrations; 3) consider the human endocrinology literature more thoroughly and perhaps take more multimarker approaches; 4) better consider the social environment, including audience and dyadic familiarity effects; and 5) apply our findings to conservation issues.

Beyond catecholamines: Measuring autonomic responses to psychosocial context

Despite longstanding interest among human biologists in autonomic responses to socioecological context or culture change, the adoption of autonomic measures has been limited by methodological challenges. Catecholamine secretion is the most direct measure, but not all study designs are amenable to urinary sampling, and blood pressure lacks specificity to the parasympathetic or sympathetic division of the autonomic nervous system. This article reviews three alternative approaches for measuring autonomic responses: salivary α-amylase as a nonspecific autonomic marker, respiratory sinus arrhythmia as a specific parasympathetic marker, and the pre-ejection period as a specific sympathetic marker. Study design considerations are discussed in detail, including ambulatory sampling protocols that permit the evaluation of autonomic responses to everyday life. Researchers interested in how culture and social experience "get under the skin," as well as those concerned with the evolution of social engagement, can benefit from these well-validated biomarkers that are nevertheless relatively novel in human biology. Am. J. Hum. Biol. 28:309-317, 2016. © 2015 Wiley Periodicals, Inc.

The symphonic structure of childhood stress reactivity: patterns of sympathetic, parasympathetic, and adrenocortical responses to psychological challenge

Despite widespread recognition that the physiological systems underlying stress reactivity are well coordinated at a neurobiological level, surprisingly little empirical attention has been given to delineating precisely how the systems actually interact with one another when confronted with stress. We examined cross-system response proclivities in anticipation of and following standardized laboratory challenges in 664 4- to 14-year-olds from four independent studies. In each study, measures of stress reactivity within both the locus coeruleus-norepinephrine system (i.e., the sympathetic and parasympathetic branches of the autonomic nervous system) and the corticotrophin releasing hormone system (i.e., the hypothalamic-pituitary-adrenal axis) were collected. Latent profile analyses revealed six distinctive patterns that recurred across the samples: moderate reactivity (average cross-system activation; 52%-80% of children across samples), parasympathetic-specific reactivity (2%-36%), anticipatory arousal (4%-9%), multisystem reactivity (7%-14%), hypothalamic-pituitary-adrenal axis specific reactivity (6%-7%), and underarousal (0%-2%). Groups meaningfully differed in socioeconomic status, family adversity, and age. Results highlight the sample-level reliability of children's neuroendocrine responses to stress and suggest important cross-system regularities that are linked to development and prior experiences and may have implications for subsequent physical and mental morbidity.