Social deprivation and the HPA axis in early development

Effects of social environments on male primate HPG and HPA axis developmental programming

Developmental plasticity is particularly important for humans and other primates because of our extended period of growth and maturation, during which our phenotypes adaptively respond to environmental cues. The hypothalamus-pituitary-gonadal (HPG) and hypothalamus-pituitary-adrenal (HPA) axes are likely to be principal targets of developmental "programming" given their roles in coordinating fitness-relevant aspects of the phenotype, including sexual development, adult reproductive and social strategies, and internal responses to the external environment. In social animals, including humans, the social environment is believed to be an important source of cues to which these axes may adaptively respond. The effects of early social environments on the HPA axis have been widely studied in humans, and to some extent, in other primates, but there are still major gaps in knowledge specifically relating to males. There has also been relatively little research examining the role that social environments play in developmental programming of the HPG axis or the HPA/HPG interface, and what does exist disproportionately focuses on females. These topics are likely understudied in males in part due to the difficulty of identifying developmental milestones in males relative to females and the general quiescence of the HPG axis prior to maturation. However, there are clear indicators that early life social environments matter for both sexes. In this review, we examine what is known about the impact of social environments on HPG and HPA axis programming during male development in humans and nonhuman primates, including the role that epigenetic mechanisms may play in this programming. We conclude by highlighting important next steps in this research area.

Interaction of serotonin/GLP-1 circuitry in a dual preclinical model for psychiatric disorders and metabolic dysfunction

Isolation of rodents throughout adolescence is known to induce many behavioral abnormalities which resemble neuropsychiatric disorders. Separately, this paradigm has also been shown to induce long-term metabolic changes consistent with a pre-diabetic state. Here, we investigate changes in central serotonin (5-HT) and glucagon-like peptide 1 (GLP-1) neurobiology that dually accompany behavioral and metabolic outcomes following social isolation stress throughout adolescence. We find that adolescent-isolation mice exhibit elevated blood glucose levels, impaired peripheral insulin signaling, altered pancreatic function, and fattier body composition without changes in bodyweight. These mice further exhibited disruptions in sleep and enhanced nociception. Using bulk and spatial transcriptomic techniques, we observe broad changes in neural 5-HT, GLP-1, and appetitive circuits. We find 5-HT neurons of adolescent-isolation mice to be more excitable, transcribe fewer copies of Glp1r (mRNA; GLP-1 receptor), and demonstrate resistance to the inhibitory effects of the GLP-1R agonist semaglutide on action potential thresholds. Surprisingly, we find that administration of semaglutide, commonly prescribed to treat metabolic syndrome, induced deficits in social interaction in group-housed mice and rescued social deficits in isolated mice. Overall, we find that central 5-HT circuitry may simultaneously influence mental well-being and metabolic health in this model, via interactions with GLP-1 and proopiomelanocortin circuitry.

Genotypic variation in the promoter region of the CRH-248 gene interacts with early rearing experiences to disrupt the development of the HPA axis in infant rhesus macaques (Macaca mulatta)

Aberrant functioning of the hypothalamic-pituitary-adrenal (HPA) axis is a hallmark of conditions such as depression, anxiety disorders, and post-traumatic stress disorder. Early-life adversity and genetic variation can interaction to disrupt HPA axis regulation, potentially contributing to certain forms of psychopathology. This study employs a rhesus macaque model to investigate how early parental neglect interacts with a single nucleotide polymorphism within the promoter region of the corticotropin-releasing hormone (CRH-248) gene, impacting the development of the HPA axis. For the initial six months of life, 307 rhesus monkey infants (n = 146 females, n = 161 males) were either reared with their mothers (MR) in conditions emulating the natural environment (control group) or raised without maternal care in groups with constant or 3-hours daily access to same-aged peers (NR). Blood samples collected on days 30, 60, 90, and 120 of life under stressful conditions were assayed for plasma cortisol and adrenocorticotropic hormone (ACTH) concentrations. Findings revealed that NR subjects exhibited a significant blunting of both ACTH and cortisol concentrations. Notably, there was a gene-by-environment interaction observed for ACTH and cortisol levels, with NR subjects with the polymorphism displaying higher ACTH concentrations and lower cortisol concentrations. To the extent that these results generalize to humans, they suggest that early parental neglect may render individuals vulnerable to HPA axis dysfunction, a susceptibility that is modulated by CRH-248 genotype-a gene-by-environment interaction that leaves a lasting developmental signature.

Linking specific biological signatures to different childhood adversities: findings from the HERO project

BACKGROUND

Although investigations have begun to differentiate biological and neurobiological responses to a variety of adversities, studies considering both endocrine and immune function in the same datasets are limited.

METHODS

Associations between proximal (family functioning, caregiver depression, and anxiety) and distal (SES-D; socioeconomic disadvantage) early-life adversities with salivary inflammatory biomarkers (IL-1β, IL-6, IL-8, and TNF-α) and hair HPA markers (cortisol, cortisone, and dehydroepiandrosterone) were examined in two samples of young U.S. children (N = 142; N = 145).

RESULTS

Children exposed to higher SES-D had higher levels of TNF-α (B = 0.13, p = 0.011), IL-1β (B = 0.10, p = 0.033), and DHEA (B = 0.16, p = 0.011). Higher family dysfunction was associated with higher cortisol (B = 0.08, p = 0.033) and cortisone (B = 0.05, p = 0.003). An interaction between SES-D and family dysfunction was observed for cortisol levels (p = 0.020) whereby children exposed to lower/average levels of SES-D exhibited a positive association between family dysfunction and cortisol levels, whereas children exposed to high levels of SES-D did not. These findings were partially replicated in the second sample.

CONCLUSIONS

Our results indicate that these biological response systems may react differently to different forms of early-life adversity.

IMPACT

Different forms of early-life adversity have varied stress signatures, and investigations of early-life adversities with inflammation and HPA markers are lacking. Children with higher socioeconomic disadvantage had higher TNF-α, IL-1β, and DHEA. Higher family dysfunction was associated with higher hair cortisol and cortisone levels, and the association between family dysfunction and cortisol was moderated by socioeconomic disadvantage. Biological response systems (immune and endocrine) were differentially associated with distinct forms of early-life adversities.

Post-weaning social isolation in male mice leads to abnormal aggression and disrupted network organization in the prefrontal cortex: Contribution of parvalbumin interneurons with or without perineuronal nets

Adverse social experiences during childhood increase the risk of developing aggression-related psychopathologies. The prefrontal cortex (PFC) is a key regulator of social behavior, where experience-dependent network development is tied to the maturation of parvalbumin-positive (PV+) interneurons. Maltreatment in childhood could impact PFC development and lead to disturbances in social behavior during later life. However, our knowledge regarding the impact of early-life social stress on PFC operation and PV+ cell function is still scarce. Here, we used post-weaning social isolation (PWSI) to model early-life social neglect in mice and to study the associated neuronal changes in the PFC, additionally distinguishing between the two main subpopulations of PV+ interneurons, i.e. those without or those enwrapped by perineuronal nets (PNN). For the first time to such detailed extent in mice, we show that PWSI induced disturbances in social behavior, including abnormal aggression, excessive vigilance and fragmented behavioral organization. PWSI mice showed altered resting-state and fighting-induced co-activation patterns between orbitofrontal and medial PFC (mPFC) subregions, with a particularly highly elevated activity in the mPFC. Surprisingly, aggressive interaction was associated with a higher recruitment of mPFC PV+ neurons that were surrounded by PNN in PWSI mice that seemed to mediate the emergence of social deficits. PWSI did not affect the number of PV+ neurons and PNN density, but enhanced PV and PNN intensity as well as cortical and subcortical glutamatergic drive onto mPFC PV+ neurons. Our results suggest that the increased excitatory input of PV+ cells could emerge as a compensatory mechanism for the PV+ neuron-mediated impaired inhibition of mPFC layer 5 pyramidal neurons, since we found lower numbers of GABAergic PV+ puncta on the perisomatic region of these cells. In conclusion, PWSI leads to altered PV-PNN activity and impaired excitatory/inhibitory balance in the mPFC, which possibly contributes to social behavioral disruptions seen in PWSI mice. Our data advances our understanding on how early-life social stress can impact the maturing PFC and lead to the development of social abnormalities in adulthood.

Involvement of a serotonin/GLP-1 circuit in adolescent isolation-induced diabetes

In 2020, stay-at-home orders were implemented to stem the spread of SARS-CoV-2 worldwide. Social isolation can be particularly harmful to children and adolescents-during the pandemic, the prevalence of obesity increased by ∼37% in persons aged 2-19. Obesity is often comorbid with type 2 diabetes, which was not assessed in this human pandemic cohort. Here, we investigated whether male mice isolated throughout adolescence develop type 2 diabetes in a manner consistent with human obesity-induced diabetes, and explored neural changes that may underlie such an interaction. We find that isolating C57BL/6J mice throughout adolescence is sufficient to induce type 2 diabetes. We observed fasted hyperglycemia, diminished glucose clearance in response to an insulin tolerance test, decreased insulin signaling in skeletal muscle, decreased insulin staining of pancreatic islets, increased nociception, and diminished plasma cortisol levels compared to group-housed control mice. Using Promethion metabolic phenotyping chambers, we observed dysregulation of sleep and eating behaviors, as well as a time-dependent shift in respiratory exchange ratio of the adolescent-isolation mice. We profiled changes in neural gene transcription from several brain areas and found that a neural circuit between serotonin-producing and GLP-1-producing neurons is affected by this isolation paradigm. Overall, spatial transcription data suggest decreased serotonin neuron activity (via decreased GLP-1-mediated excitation) and increased GLP-1 neuron activity (via decreased serotonin-mediated inhibition). This circuit may represent an intersectional target to further investigate the relationship between social isolation and type 2 diabetes, as well as a pharmacologically-relevant circuit to explore the effects of serotonin and GLP-1 receptor agonists.

Article Highlights

Isolating C57BL/6J mice throughout adolescence is sufficient to induce type 2 diabetes, presenting with fasted hyperglycemia.Adolescent-isolation mice have deficits in insulin responsiveness, impaired peripheral insulin signaling, and decreased pancreatic insulin production.Transcriptional changes across the brain include the endocannabinoid, serotonin, and GLP-1 neurotransmitters and associated receptors. The neural serotonin/GLP-1 circuit may represent an intersectional target to further investigate the relationship between social isolation and type 2 diabetes. Serotonin-producing neurons of adolescent-isolation mice produce fewer transcripts for the GLP-1 receptor, and GLP-1 neurons produce fewer transcripts for the 5-HT 1A serotonin receptor.

Lasting impact of postnatal maternal separation on the developing BNST: Lifelong socioemotional consequences

Nearly one percent of children in the US experience childhood neglect or abuse, which can incite lifelong emotional and behavioral disorders. Many studies investigating the neural underpinnings of maleffects inflicted by early life stress have largely focused on dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis. Newer veins of evidence suggest that exposure to early life stressors can interrupt neural development in extrahypothalamic areas as well, including the bed nucleus of the stria terminalis (BNST). One widely used approach in this area is rodent maternal separation (MS), which typically consists of separating pups from the dam for extended periods of time, over several days during the first weeks of postnatal life - a time when pups are highly dependent on maternal care for survival. MS has been shown to incite myriad lasting effects not limited to increased anxiety-like behavior, hyper-responsiveness to stressors, and social behavior deficits. The behavioral effects of MS are widespread and thus unlikely to be limited to hypothalamic mechanisms. Recent work has highlighted the BNST as a critical arbiter of some of the consequences of MS, especially socioemotional behavioral deficits. The BNST is a well-documented modulator of anxiety, reward, and social behavior by way of its connections with hypothalamic and extra-hypothalamic systems. Moreover, during the postnatal period when MS is typically administered, the BNST undergoes critical neural developmental events. This review highlights evidence that MS interferes with neural development to permanently alter BNST circuitry, which may account for a variety of behavioral deficits seen following early life stress. This article is part of the Special Issue on 'Fear, Anxiety and PTSD'.

Early childhood stress responses to psychosocial stressors: The state of the science

The aim of this systematic review was to better understand whether and to what extent psychosocial stressors are associated with hypothalamic-pituitary-adrenal axis or autonomic nervous system stress responses in young children (1-6 years of age). Studies were classified by psychosocial stressors from the ecobiodevelopmental model: social and economic resources, maternal mental health, parent-child relationships, and the physical environment. Of the 2388 identified studies, 32 met full inclusion criteria, including over 9107 children. Child physiologic stress responses were measured as hair and urinary cortisol and cortisone, salivary diurnal and reactive cortisol, salivary reactive alpha-amylase, and respiratory sinus arrhythmia. There were 107 identified relations between psychosocial stressors and physiologic stress responses. Nearly two thirds of these relations suggested that children have dysregulated stress responses as either significantly blunted (n = 27) or increased (n = 37); 43 relations were not significant. Children most consistently had significantly dysregulated stress responses if they experienced postnatal maternal depression or anxiety. Some reasons for the mixed findings may be related to characteristics of the child (i.e., moderators) or stressor, how the stress response or psychosocial stressor was measured, unmeasured variables (e.g., caregiving buffering), researcher degrees of freedom, or publication bias.

Intervening With Attachment and Biobehavioral Catch-Up to Reduce Behavior Problems Among Children Adopted Internationally: Evidence From a Randomized Controlled Trial

Children who have been adopted internationally often exhibit persistent behavior problems. The current study assessed the efficacy of the Attachment and Biobehavioral Catch-up intervention (ABC; Dozier & Bernard, 2019) for reducing behavior problems in 122 children adopted internationally. Behavior problems were measured via parent-report using the Brief Infant Toddler Social Emotional Assessment at a pre-intervention visit and after the intervention when children were between 18 and 36 months. Children's behavior problems were also observed using the Disruptive Behavior Diagnostic Observation Schedule (DB-DOS) after the intervention when children were 48 and 60 months. Parents who received ABC reported fewer child behavior problems than parents who received the control intervention immediately after the intervention through 1.5 years post-intervention. Additionally, children whose parents received ABC exhibited fewer behavior problems within the parent context of the DB-DOS when they were 48 months old (2 years post-intervention) than children whose parents received the control intervention. There were no significant intervention effects on children's observed behavior problems within the examiner contexts. These results support the efficacy of ABC in reducing behavior problems among children adopted internationally. Trial registration: ClinicalTrials.gov NCT00816621.

Let's Be Ready: COVID-19 Related Restrictions Can Lead to an Outbreak of Social-Communication Problems in Children

The article abstract is not available.

Mechanisms of Cardiometabolic Health Outcomes and Disparities: What Characteristics of Chronic Stressors are Linked to HPA-Axis Dysregulation?

Objectives: Chronic stressors are associated with cardiometabolic health conditions and disparities. Mechanisms linking stressors and health remain poorly understood. Methods: Two cohort studies (Cardiac Rehabilitation And The Experience [CREATE] and Tracking Risk Identification for Adult Diabetes [TRIAD]) with harmonized variables were used to examine relationships between six types of chronic stressors in adulthood and Hypothalamic-Pituitary-Adrenal (HPA) axis dysregulation, as indicated by blunted diurnal cortisol slopes, which are stress-sensitive biomarkers implicated in cardiometabolic health (merged N = 213, mean age 61, 18% Black). A secondary aim was to explore whether these chronic stressors accounted for Black-White disparities in HPA axis regulation. Results: Some chronic stressors were linked to HPA axis dysregulation, with recent stressors most salient (b = 0.00353, SE = 0.00133, p = .008). Black-White disparities in HPA axis regulation persisted after controlling for racial differences in chronic stressors, which reduced the disparity 11.46%. Discussion: Chronic stressors in adulthood may increase risk for HPA axis dysregulation and associated cardiometabolic health outcomes but may not be a key factor in racial disparities.

Bridging skin, brain, and behavior to understand pleasurable social touch

Social touch-the affiliative skin-to-skin contact between individuals-can rapidly evoke emotions of comfort, pleasure, or calm, and is essential for mental and physical well-being. Physical isolation from social support can be devastating. During the COVID-19 pandemic, we observed a global increase in suicidal ideation, anxiety, domestic violence, and worsening of pre-existing physical conditions, alerting society to our need to understand the neurobiology of social touch and how it promotes normal health. Gaining a mechanistic understanding of how sensory neuron stimulation induces pleasure, calm, and analgesia may reveal untapped therapeutic targets in the periphery for treatment of anxiety and depression, as well as social disorders and traumas in which social touch becomes aversive. Bridging the gap between stimulation in the skin and positive affect in the brain-especially during naturally occurring social touch behaviors-remains a challenge to the field. However, with advances in mouse genetics, behavioral quantification, and brain imaging approaches to measure neuronal firing and neurochemical release, completing this mechanistic picture may be on the horizon. Here, we summarize some exciting new findings about social touch in mammals, emphasizing both the peripheral and central nervous systems, with attempts to bridge the gap between external stimulation and internal representations in the brain.

Autonomic reactivity to social rejection, peer difficulties, and the buffering effects of adolescent friendships following early psychosocial deprivation

Autonomic nervous system reactivity has been posited to be a mechanism contributing to social and emotional problems among children exposed to early adversity. Leveraging data from the Bucharest Early Intervention Project, a longitudinal randomized controlled trial of foster care versus institutional care of abandoned children in Romania, we assessed whether altered sympathetic reactivity to peer rejection feedback in early adolescence mediated the relation between early institutional rearing and peer problems in later adolescence. We also assessed whether adolescent friendship quality or randomized placement in foster care early in life moderated these associations. Participants include 68 institutionalized children randomized to care as usual, 68 institutionalized children randomized to foster care, and 135 never-institutionalized children. At age 12, participants reported friendship quality with respect to a best friend and completed a social rejection task while electrocardiogram and impedance cardiography were recorded. Sympathetic nervous system reactivity to rejection feedback was assessed using preejection period (PEP). At ages 12 and 16, peer problems were reported by parents. Mediation analysis revealed that less PEP reactivity to social rejection at age 12 partially mediated the association between early institutionalization and greater peer problems at age 16. Further moderated mediation analysis revealed that this indirect effect was evidenced among previously institutionalized youths with low, but not high, quality friendships. We did not observe foster care intervention effects. These findings suggest that altered sympathetic reactivity to social rejection might be a mechanism linking early institutionalization to social difficulties into adolescence, however, positive adolescent friendships may buffer these effects. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Effects of social and emotional context on neural activation and synchrony during movie viewing

Sharing emotional experiences impacts how we perceive and interact with the world, but the neural mechanisms that support this sharing are not well characterized. In this study, participants (N = 52) watched videos in an MRI scanner in the presence of an unfamiliar peer. Videos varied in valence and social context (i.e., participants believed their partner was viewing the same (joint condition) or a different (solo condition) video). Reported togetherness increased during positive videos regardless of social condition, indicating that positive contexts may lessen the experience of being alone. Two analysis approaches were used to examine both sustained neural activity averaged over time and dynamic synchrony throughout the videos. Both approaches revealed clusters in the medial prefrontal cortex that were more responsive to the joint condition. We observed a time‐averaged social‐emotion interaction in the ventromedial prefrontal cortex, although this region did not demonstrate synchrony effects. Alternatively, social‐emotion interactions in the amygdala and superior temporal sulcus showed greater neural synchrony in the joint compared to solo conditions during positive videos, but the opposite pattern for negative videos. These findings suggest that positive stimuli may be more salient when experienced together, suggesting a mechanism for forming social bonds.

What was learned from studying the effects of early institutional deprivation

The effect of experiences in infancy on human development is a central question in developmental science. Children raised in orphanage-like institutions for their first year or so of life and then adopted into well-resourced and supportive families provide a lens on the long-term effects of early deprivation and the capacity of children to recover from this type of early adversity. While it is challenging to identify cause-and-effect relations in the study of previously institutionalized individuals, finding results that are consistent with animal experimental studies and the one randomized study of removal from institutional care support the conclusion that many of the outcomes for these children were induced by early institutional deprivation. This review examines the behavioral and neural evidence for altered executive function, declarative memory, affective disorders, reward processing, reactivity to threat, risk-taking and sensation-seeking. We then provide a brief overview of the neurobiological mechanisms that may transduce early institutional experiences into effects on brain and behavior. In addition, we discuss implications for policy and practice.

Social isolation and its impact on child and adolescent development: a systematic review

OBJECTIVE

This study aims to analyze the effects of social isolation on children's and teenagers' development, with emphasis on the possible impacts over their physical and mental health.

DATA SOURCE

Review of the literature following the standards of PRISMA using the SciELO, LILACS and PubMed databases. The following key-words were used: "social isolation" and "child development", "quarantine" and "adolescent development" according to the Medical Subject Headings (MESH) and their translation to the Portuguese. Studies in English, Portuguese and Spanish from inception were included.

DATA SYNTHESIS

519 studies were screened and 12 were included in the systematic review. Five of those focused the psychology and social issues, two of them the effects of pandemics on these issues; four studies reported on impacts on general health and two consequences over the hypothalamus- hypophysis - adrenal axis and the cognitive and social development.

CONCLUSIONS

The review shows a strong association between social isolation and anxiety and depression in children and adolescents. Social isolation leads to higher levels of cortisol and worse cognitive development. Therefore, the mental and physical health of children and adolescents need a careful follow up by health professionals during and after the COVID-19 pandemic.

Preventing Childhood Toxic Stress: Partnering With Families and Communities to Promote Relational Health

By focusing on the safe, stable, and nurturing relationships (SSNRs) that buffer adversity and build resilience, pediatric care is on the cusp of a paradigm shift that could reprioritize clinical activities, rewrite research agendas, and realign our collective advocacy. Driving this transformation are advances in developmental sciences as they inform a deeper understanding of how early life experiences, both nurturing and adverse, are biologically embedded and influence outcomes in health, education, and economic stability across the life span. This revised policy statement on childhood toxic stress acknowledges a spectrum of potential adversities and reaffirms the benefits of an ecobiodevelopmental model for understanding the childhood origins of adult-manifested disease and wellness. It also endorses a paradigm shift toward relational health because SSNRs not only buffer childhood adversity when it occurs but also promote the capacities needed to be resilient in the future. To translate this relational health framework into clinical practice, generative research, and public policy, the entire pediatric community needs to adopt a public health approach that builds relational health by partnering with families and communities. This public health approach to relational health needs to be integrated both vertically (by including primary, secondary, and tertiary preventions) and horizontally (by including public service sectors beyond health care). The American Academy of Pediatrics asserts that SSNRs are biological necessities for all children because they mitigate childhood toxic stress responses and proactively build resilience by fostering the adaptive skills needed to cope with future adversity in a healthy manner.

Pubertal transition with current life stress and support alters longitudinal diurnal cortisol patterns in adolescents exposed to early life adversity

Current and early life stress (ELS) are associated with diurnal cortisol patterns, which themselves are associated with mental and physical health. The pubertal recalibration hypothesis suggests that the social environment can impact dysregulated cortisol patterns for previously ELS-exposed youth as they transition through puberty. This study examined longitudinal change in cortisol awakening response (CAR) and diurnal slope (DS) across puberty as a function of ELS in infancy, current stress, and social support (N = 290, 7-17 years). The CAR and DS were examined thrice annually with an accelerated longitudinal design with nurse-assessed puberty to assess associations between diurnal cortisol and pubertal recalibration with ELS and the current social environment. Exposure to ELS was associated with less steep DS but not changes in CAR, and no evidence of pubertal calibration was found. The DS became less steep for youth in later pubertal stages and as youth progressed through puberty. The CAR was steeper for youth in later pubertal stages. Across the cohort, current life stress and support were associated with changes in the DS and the CAR through the pubertal transition. The pubertal stage and the peripubertal and pubertal social environment may have important implications for adrenocortical functioning with or without exposure to ELS.

Hyper- and hypo-cortisol functioning in post-institutionalized adolescents: The role of severity of neglect and context

Understanding the developmental timing of stress exposure may help inform mechanisms underlying how stress "gets under the skin" and influences the stress response system, including the HPA axis and its end-product cortisol. Early adversity may be particularly detrimental; however, it is difficult to disentangle the timing of adversity from its cumulative burden because there is typically high continuity between early and later adversity. Moreover, context and the different stressors inherent in various contexts may interact with stress exposure to influence psychophysiological functioning. To address this issue, we examined adolescents who had been reared in institutions and suffered neglect or social deprivation ranging from approximately six months to several years of life prior to adoption into U.S. homes. We focused on the stress hormone cortisol because it can reflect continued regulatory problems in youth, even years after youth transition to typical homes. We examined cortisol morning levels and diurnal rhythms across multiple contexts (home, school, lab) on 5 separate days in 41 post-institutionalized youth and 78 comparison youth. Employing hierarchical linear modeling, we found that when assessed in the lab, post-institutionalized (PI) youth displayed lower morning cortisol levels and flatter diurnal slopes than the control youth. Yet at home, PI youth displayed higher morning cortisol levels than the control youth. In addition to group effects, we also examined severity of early adversity and found that PI kids who had endured the most severe early adversity displayed lower home cortisol levels than controls. No significant predictors of diurnal cortisol on school days were identified. These data fit with the notion that the HPA axis is impacted by early adversity, even years after adoption, and with emerging theories that postulate that stress physiology calibrates within youth to help them adapt to their context. In the case of severe early adversity, the cost of such adaptation may not be desirable. It also highlights the important role of context when assessing HPA axis activity, particularly in post-institutionalized youth.

Longitudinal changes in amygdala, hippocampus and cortisol development following early caregiving adversity

Although decades of research have shown associations between early caregiving adversity, stress physiology and limbic brain volume (e.g., amygdala, hippocampus), the developmental trajectories of these phenotypes are not well characterized. In the current study, we used an accelerated longitudinal design to assess the development of stress physiology, amygdala, and hippocampal volume following early institutional care. Previously Institutionalized (PI; N = 93) and comparison (COMP; N = 161) youth (ages 4–20 years old) completed 1–3 waves of data collection, each spaced approximately 2 years apart, for diurnal cortisol (N = 239) and structural MRI (N = 156). We observed a developmental shift in morning cortisol in the PI group, with blunted levels in childhood and heightened levels in late adolescence. PI history was associated with reduced hippocampal volume and reduced growth rate of the amygdala, resulting in smaller volumes by adolescence. Amygdala and hippocampal volumes were also prospectively associated with future morning cortisol in both groups. These results indicate that adversity-related physiological and neural phenotypes are not stationary during development but instead exhibit dynamic and interdependent changes from early childhood to early adulthood.

Enhancing diurnal cortisol regulation among young children adopted internationally: A randomized controlled trial of a parenting-based intervention

Children who have been adopted internationally commonly experience institutional care and other forms of adversity prior to adoption that can alter the functioning of the hypothalamic-pituitary-adrenal (HPA) axis. In particular, internationally adopted children tend to have blunted diurnal declines compared to children raised in their birth families. The Attachment and Biobehavioral Catch-Up (ABC) intervention was developed to enhance young children's biological and behavioral regulation by promoting sensitive parenting. The current study used a randomized controlled trial to assess whether ABC improved the diurnal functioning of the HPA axis among 85 children who had been adopted internationally when they were between the ages of 4 and 33 months (M = 16.12). Prior to the intervention, there were no significant differences in diurnal cortisol production between children whose parents were randomly assigned to receive ABC and children whose parents were randomly assigned to receive a control intervention. After the intervention, children whose parents had received the ABC intervention exhibited steeper declines in cortisol levels throughout the day than children whose parents had received the control intervention. These results indicate that the ABC intervention is effective in enhancing a healthy pattern of diurnal HPA axis regulation for young children who have been adopted internationally.

Environmental determinants of physiological reactivity to stress: The interacting effects of early life deprivation, caregiving quality, and stressful life events

Children who spend their early lives in institutions experience profound psychosocial deprivation that is associated with altered stress response system development. Here, we used data from a longitudinal randomized controlled trial of foster care for institutionally reared children to examine whether caregiving quality and stressful life events (SLEs) in early adolescence (age 12) influence patterns of hypothalamic-pituitary-adrenal (HPA) axis and sympathetic nervous system (SNS) reactivity. Controlling for the effect of institutional care, higher caregiving quality at age 12 was associated with heightened cortisol and SNS reactivity. However, moderation analysis revealed that the latter effect was only observed among never-institutionalized children, whereas ever-institutionalized children demonstrated a persistently blunted SNS response regardless of recent caregiving quality. Among institutionally reared children, SLEs interacted with prior random assignment to foster care, such that those placed in foster care early in development had a SNS response that approximated never-institutionalized children when SLEs at age 12 were low. In contrast, SNS reactivity was persistently blunted among those with prolonged deprivation, regardless of recent SLEs. Early-life deprivation is associated with persistent blunting of stress response systems, but normalization may be achievable if SLEs are limited following placement into enriched family-based care.

Challenges in researching the immune pathways between early life adversity and psychopathology

Exposure to childhood adversity is a critical risk factor for the development of psychopathology. A growing field of research examines how exposure to childhood adversity is translated into biological risk for psychopathology through alterations in immune system functioning, most notably heightened levels of inflammation biomarkers. Though our knowledge about how childhood adversity can instantiate biological risk for psychopathology is growing, there remain many challenges and gaps in the field to understand how inflammation from childhood adversity contributes to psychopathology. This paper reviews research on the inflammatory outcomes arising from childhood adversity and presents four major challenges that future research must address: (a) the measurement of childhood adversity, (b) the measurement of inflammation, (c) the identification of mediators between childhood adversity and inflammation, and (d) the identification of moderators of inflammatory outcomes following childhood adversity. We discuss synergies and inconsistencies in the literature to summarize the current understanding of the association between childhood adversity, a proinflammatory phenotype, and the biological risk for psychopathology. We discuss the clinical implications of the inflammatory links between childhood adversity and psychopathology, including possibilities for intervention. Finally, this review conclude by delineates future directions for research, including issues of how best to detect, prevent, and understand these “hidden wounds” of childhood adversity.

The persistent associations between early institutional care and diurnal cortisol outcomes among children adopted internationally

Young children in institutional care experience conditions that are incompatible with their needs for attachment relationships. As a result, early institutionalization is expected to have lasting effects on the regulation of the hypothalamic-pituitary-adrenocortical (HPA) axis. The current study tested whether early institutionalization has persistent consequences for diurnal HPA axis outcomes among 130 children who had been adopted internationally between the ages of 6 and 48 months. Daily cortisol samples were collected from children at two time points: shortly after adoption (average of 5.3 months after adoption) and approximately 3 years later (average of 39.2 months after adoption). Shortly after adoption, children who had experienced a long duration of institutional care had lower morning cortisol levels and more blunted declines in cortisol across the day than children who experienced minimal or no institutional care. Three years later, children who had experienced a long duration of institutionalization continued to exhibit low morning cortisol levels and also exhibited low bedtime cortisol levels. Altogether, these results support the idea that early adversity results in the downregulation of the HPA axis and suggest that the effects of institutionalization on HPA axis functioning may persist several years after children are adopted into highly enriched families.

Early adversity and children's regulatory deficits: Does postadoption parenting facilitate recovery in postinstitutionalized children?

Children reared in orphanages typically experience the lack of stable, reliable caregivers and are at increased risk for deficits in regulatory abilities including difficulties in inhibitory control, attention, and emotion regulation. Although adoption results in a radical shift in caregiving quality, there remains variation in postadoption parenting, yet little research has examined postadoption parenting that may promote recovery in children experiencing early life adversity in the form of institutional care. Participants included 93 postinstitutionalized children adopted between 15 and 36 months of age and 52 nonadopted same-aged peers. Parenting was assessed four times during the first 2 years postadoption (at 2, 8, 16, and 24 months postadoption) and children's regulation was assessed at age 5 (M age = 61.68 months) and during kindergarten (M age = 71.55 months). Multiple parenting dimensions including sensitivity/responsiveness, structure/limit setting, and consistency in routines were examined. Both parental sensitivity and structure moderated the effect of preadoption adversity on children's emotion regulation while greater consistency was associated with better inhibitory control and fewer attention problems. Results support the notion that postadoption parenting during toddlerhood and the early preschool years promotes better regulation skills following early adversity.

Parental sensitivity mediates the sustained effect of Attachment and Biobehavioral Catch-up on cortisol in middle childhood: A randomized clinical trial

IMPORTANCE

Parenting interventions have been found to normalize cortisol regulation among high-risk children early in development; it is important to investigate the sustainability of these effects and their mechanisms, given the maladaptive outcomes associated with cortisol dysregulation.

OBJECTIVE

To determine whether the Attachment and Biobehavioral Catch-up (ABC) intervention, implemented in infancy, predicts cortisol regulation in middle childhood via changes in early parental sensitivity.

DESIGN

Double blind randomized clinical trial design; started January 2006, the follow-up for this project concluded March 2016.

SETTING

Parents of children under age 2 referred from child protective services agencies in a large, mid-Atlantic city.

PARTICIPANTS

103 parent-child dyads (45.6% female children) with histories of child protective services involvement, randomly assigned to receive ABC (n = 45) or a control intervention (n = 58); in infancy, the children's ages ranged from 1.60 to 25.30 months (M = 9.87 months); at the middle childhood follow-up, they ranged from 8.0 to 11.0 years old (M = 8.52 years).

INTERVENTIONS

Both conditions included 10-week, in-home, manualized interventions. The experimental condition, ABC, has 3 primary targets for parents: increasing nurturance to child distress, increasing following the child's lead, and decreasing frightening behavior. The control intervention, Developmental Education for Families (DEF), is an adaptation of a program focused on enhancing cognitive and language development.

MAIN OUTCOMES AND MEASURES

Parental sensitivity was coded from a semi-structured interaction task between the parent and child in early childhood. Middle childhood diurnal cortisol slopes were modeled by collecting salivary cortisol samples from children at wake-up and bedtime over the course of 3 consecutive days.

RESULTS

ABC participation in infancy was associated with increased parental sensitivity post-intervention, β = 0.28, p = .004, and this increased sensitivity predicted steeper decline across the day in children's cortisol concentration in middle childhood, β = -.53, p = .002. The indirect effect of ABC on cortisol regulation via sensitivity was significant, β = -0.15, p = .038.

CONCLUSIONS AND RELEVANCE

ABC has an indirect effect on middle childhood diurnal cortisol regulation via parental sensitivity; future research should seek to determine how this enhanced neurobiological regulation relates to children's behavioral, socioemotional, and psychological outcomes.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT02093052.

Normative range parenting and the developing brain: A scoping review and recommendations for future research

Studies of early adversity such as trauma, abuse, and neglect highlight the critical importance of quality caregiving in brain development and mental health. However, the impact of normative range variability in caregiving on such biobehavioral processes remains poorly understood. Thus, we lack an essential foundation for understanding broader, population-representative developmental mechanisms of risk and resilience. Here, we conduct a scoping review of the extant literature centered on the question, "Is variability in normative range parenting associated with variability in brain structure and function?" After removing duplicates and screening by title, abstract, and full-text, 23 records were included in a qualitative review. The most striking outcome of this review was not only how few studies have explored associations between brain development and normative range parenting, but also how little methodological consistency exists across published studies. In light of these limitations, we propose recommendations for future research on normative range parenting and brain development. In doing so, we hope to facilitate evidence-based research that will help inform policies and practices that yield optimal developmental trajectories and mental health as well as extend the literature on the neurodevelopmental impact of early life stress.

Neurobiological Markers of Resilience to Early-Life Adversity During Adolescence

Early-life adversity (ELA) exposure (e.g., trauma, abuse, neglect, or institutional care) is a precursor to poor physical and mental health outcomes and is implicated in 30% of adult mental illness. In recent decades, ELA research has increasingly focused on characterizing factors that confer resilience to ELA and on identifying opportunities for intervention. In this review, we describe recent behavioral and neurobiological resilience work that suggests that adolescence (a period marked by heightened plasticity, development of key neurobiological circuitry, and sensitivity to the social environment) may be a particularly opportune moment for ELA intervention. We review intrapersonal factors associated with resilience that become increasingly important during adolescence (specifically, reward processing, affective learning, and self-regulation) and describe the contextual factors (family, peers, and broader social environment) that modulate them. In addition, we describe how the onset of puberty interacts with each of these factors, and we explore recent findings that point to possible "pubertal recalibration" of ELA exposure as an opportunity for intervention. We conclude by describing considerations and future directions for resilience research in adolescents, with a focus on understanding developmental trajectories using dimensional and holistic models of resilience.

COVID-19 and the cardiovascular system: implications for risk assessment, diagnosis, and treatment options

The novel coronavirus disease (COVID-19) outbreak, caused by SARS-CoV-2, represents the greatest medical challenge in decades. We provide a comprehensive review of the clinical course of COVID-19, its comorbidities, and mechanistic considerations for future therapies. While COVID-19 primarily affects the lungs, causing interstitial pneumonitis and severe acute respiratory distress syndrome (ARDS), it also affects multiple organs, particularly the cardiovascular system. Risk of severe infection and mortality increase with advancing age and male sex. Mortality is increased by comorbidities: cardiovascular disease, hypertension, diabetes, chronic pulmonary disease, and cancer. The most common complications include arrhythmia (atrial fibrillation, ventricular tachyarrhythmia, and ventricular fibrillation), cardiac injury [elevated highly sensitive troponin I (hs-cTnI) and creatine kinase (CK) levels], fulminant myocarditis, heart failure, pulmonary embolism, and disseminated intravascular coagulation (DIC). Mechanistically, SARS-CoV-2, following proteolytic cleavage of its S protein by a serine protease, binds to the transmembrane angiotensin-converting enzyme 2 (ACE2) -a homologue of ACE-to enter type 2 pneumocytes, macrophages, perivascular pericytes, and cardiomyocytes. This may lead to myocardial dysfunction and damage, endothelial dysfunction, microvascular dysfunction, plaque instability, and myocardial infarction (MI). While ACE2 is essential for viral invasion, there is no evidence that ACE inhibitors or angiotensin receptor blockers (ARBs) worsen prognosis. Hence, patients should not discontinue their use. Moreover, renin-angiotensin-aldosterone system (RAAS) inhibitors might be beneficial in COVID-19. Initial immune and inflammatory responses induce a severe cytokine storm [interleukin (IL)-6, IL-7, IL-22, IL-17, etc.] during the rapid progression phase of COVID-19. Early evaluation and continued monitoring of cardiac damage (cTnI and NT-proBNP) and coagulation (D-dimer) after hospitalization may identify patients with cardiac injury and predict COVID-19 complications. Preventive measures (social distancing and social isolation) also increase cardiovascular risk. Cardiovascular considerations of therapies currently used, including remdesivir, chloroquine, hydroxychloroquine, tocilizumab, ribavirin, interferons, and lopinavir/ritonavir, as well as experimental therapies, such as human recombinant ACE2 (rhACE2), are discussed.

Biological sensitivity to context in Pakistani preschoolers: Hair cortisol and family wealth are interactively associated with girls' cognitive skills

Many young children in low- and middle-income countries (LMICs) face heightened risk for experiencing environmental adversity, which is linked with poorer developmental outcomes. Children's stress physiology can shed light on why children are differentially susceptible to adversity. However, no known studies have examined whether links between adversity and children's development are moderated by children's stress physiology in LMICs. The present study revealed significant interactive effects of hair cortisol concentrations, an index of chronic physiological stress regulation, and family wealth on preschoolers' cognitive skills in rural Pakistan. In a sample of 535 4-year-old children (n = 342 girls), we found significant associations between family wealth and direct assessments of verbal intelligence, pre-academic skills, and executive functions only in girls with lower hair cortisol concentrations. Specifically, girls with lower cortisol concentrations displayed greater cognitive skills if they came from relatively wealthier families, but lower cognitive skills if they came from very poor families. There were no significant associations among boys. Results provide evidence of biological sensitivity to context among young girls in a LMIC, perhaps reflecting, in part, sex differences in daily experiences of environmental adversity.

Early Deprivation Revisited: Contemporary Studies of the Impact on Young Children of Institutional Care

There is clear evidence that early deprivation in the form of early institutional care affects children both immediately and long after they are removed from the institution. This article reviews the modern literature on the impact of institutional care from animal models to longitudinal studies in humans. Importantly, we examine the current understanding of neuroendocrine regulation in the context of early deprivation. We discuss the opportunities and limitations of studying the effects of deprivation in previously institutionalized children, review behavioral findings and related neurobiological studies, and address the physical health ramifications of institutional care. Finally, we touch on future directions for both science and intervention.

Altered immune system in offspring of rat maternal vertical sleeve gastrectomy

Obesity in women results in reduced fertility and increased complications during pregnancy. Vertical sleeve gastrectomy (VSG) effectively reduces weight, type 2 diabetes, and dyslipidemia, but is also associated with preterm and small-for-gestational age births. The mechanism by which VSG influences fetal development remains unknown. Here we hypothesize that previously reported immune changes during rat VSG pregnancy are reflected long term in the immune system of the offspring. Offspring of VSG and sham dams were evaluated at postnatal day (PND) 21 and PND60. At PND21, VSG pups have lower numbers of circulating B lymphocytes compared with sham pups (P < 0.05) and have lower transcription of lymphocyte marker Ptprc (P < 0.01) in the spleen, while other lymphocyte populations measured are not different. Total plasma IgG is higher (P < 0.01) and C-reactive protein is lower (P < 0.05) in VSG offspring compared with sham offspring at PND21. The central nervous system of VSG pups is also affected at PND21, having higher expression of Il1b mRNA (P < 0.05) and higher immunoreactivity of microglia marker, IBA1, in the hypothalamus. At PND60, the immune-hematological differences are not present; however, mRNA expression of Il1b is elevated (P < 0.001) in the spleen of VSG offspring along with markers of T cells. These data suggest that the immune system of VSG offspring is compromised early in life, but rebounds after weaning and may even become hyperactive. Future work is needed to determine whether the immune system of VSG offspring is capable of mounting a proper defense and whether other aspects of development are affected.

The psychobiological consequences of child separation at the border: lessons from research on attachment and emotion regulation

In the spring of 2018, the Attorney General of the United States issued a memorandum declaring a "zero tolerance policy" under which all adults entering the United States illegally would be criminally prosecuted, and, if traveling with minor children, forcibly separated from their children. Although the government was ordered to reunite the children with their parents it is still unclear how many children have been or remain separated. Given the high risk of permanent harm to a vulnerable population, and the fact that this risk may continue into the near future, we present a review of what nearly eight decades of scholarly research has taught us about the damaging impact of deprivation and separation from parents. The article briefly reviews the origins of attachment theory as well as empirical studies that examine the psychobiological impact on children who experienced parental deprivation or separation. The paper concludes with recommendations, for future research.

Comparison of Institutionally Reared and Maltreated Children on Socioemotional and Biological Functioning

The current study compared behavioral and adrenocortical functioning of maltreated (N = 91) and comparably aged (1.5-3 years) institutionally-reared children soon after (1.5-2.5 months) placement in foster care or adoptive homes, respectively. Foster and adoptive parents reported on the children's socioemotional competence and behavior problems, experimenters scored fear and positive affect to laboratory tasks, and diurnal cortisol measures were obtained. We sought to address whether these early contexts, characterized by different types of neglect and deprivation, have differential effects on young children's development. We found little support for the argument that either context results in uniformly poorer functioning soon after removal from adversity. Maltreated children were less fearful and more positive when exposed to both positive and novel events than institutionally-reared children. However, maltreated children were reported to have more behavior problems than did institutionally-reared children, and institutionally-reared children showed more typical declines in cortisol throughout the day than the maltreated children. These findings increase our ability to construct more targeted and effective interventions for these populations.

Early adversity, child neglect, and stress neurobiology: From observations of impact to empirical evaluations of mechanisms

Research on the effects of early life adversity, and in particular on the absence of responsive caregiving, has shown long-term impacts on well-being and development. These investigations have been conducted both in human populations and in animal models. The work has demonstrated that neglect experienced in the early years can affect not only behavior but also neurobiological functioning. In particular, studies of children in the foster care system show convergence with research on children adopted following institutional rearing in terms of dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, which produces the neuroendocrine hormone cortisol. The characteristic pattern that has been most commonly observed involves diminished diurnal cortisol production, particularly in terms of low levels of cortisol upon awakening. Notably, however, a number of evidence-based interventions for infant, toddler, and preschool-aged foster children have been shown to produce more typical patterns of cortisol production, in combination with improved behavioral, socioemotional, and foster care placement outcomes. In this paper, we review the literature on the effects of early disruptions in care on biobehavioral development, and summarize the results of the interventions for young foster children.

Working memory moderates the association between early institutional care and separation anxiety symptoms in late childhood and adolescence

Adverse caregiving, for example, previous institutionalization (PI), is often associated with emotion dysregulation that increases anxiety risk. However, the concept of developmental multifinality predicts heterogeneity in anxiety outcomes. Despite this well-known heterogeneity, more work is needed to identify sources of this heterogeneity and how these sources interact with environmental risk to influence mental health. Here, working memory (WM) was examined during late childhood/adolescence as an intra-individual factor to mitigate the risk for separation anxiety, which is particularly susceptible to caregiving adversities. A modified "object-in-place" task was administered to 110 youths (10-17 years old), with or without a history of PI. The PI youths had elevated separation anxiety scores, which were anticorrelated with morning cortisol levels, yet there were no group differences in WM. PI youths showed significant heterogeneity in separation anxiety symptoms and morning cortisol levels, and WM moderated the link between caregiving and separation anxiety and mediated the association between separation anxiety and morning cortisol in PI youth. Findings suggest that (a) institutional care exerts divergent developmental consequences on separation anxiety versus WM, (b) WM interacts with adversity-related emotion dysregulation, and (c) WM may be a therapeutic target for separation anxiety following early caregiving adversity.

Insecure Attachment and Hypothalamus-Pituitary-Adrenal Axis Functioning in People With Eating Disorders

OBJECTIVE

Childhood attachment experiences affect adult emotion regulation and ability to cope with stressors. Therefore, insecure attachment may influence the functioning of the hypothalamic-pituitary-adrenal (HPA) axis and a dysregulation of HPA axis has been found in insecure attached healthy individuals. The effects of attachment on HPA axis activity have never been investigated in eating disorders (EDs). Therefore, we assessed the relationships between insecure attachment and the cortisol awakening response (CAR) in adults with EDs.

METHODS

Seventy-eight patients with EDs (43 with anorexia nervosa, 35 with bulimia nervosa) were recruited. They completed the Experience in Close Relationships questionnaire, which provides a rating of two insecure attachment dimensions (anxiety and avoidance) and collected saliva samples to measure the CAR. Differences in the CAR between groups with high and low attachment anxiety and between groups with high and low attachment avoidance were evaluated by repeated measures two-way analysis of variance.

RESULTS

Patients with high attachment anxiety showed a reduced CAR compared with those with low attachment anxiety (F1,76 = 7.31, p = .008). The CAR did not differ between the groups with high and low attachment avoidance (F1,76 = 0.01, p = .93). Patients with high levels of insecure attachment showed a more severe eating-related psychopathology.

CONCLUSIONS

Our data show, for the first time, a specific association of the anxious attachment with the HPA axis activity in EDs and suggest a possible role of attachment in the biological vulnerability to stress of adult patients with EDs.

Homotypic and heterotypic continuity of internalizing and externalizing symptoms from ages 3 to 12: The moderating role of diurnal cortisol

Psychological symptoms that arise in early childhood can follow a multitude of patterns into adolescence, including homotypic continuity (i.e., similar symptoms over time) and heterotypic continuity (i.e., a shift in symptoms over time). However, we know very little about the factors that distinguish homotypic vs. heterotypic continuity of early internalizing and externalizing symptoms over development. In a separate line of research, diurnal cortisol has been shown to predict later internalizing and externalizing problems. In the current study, we tested whether diurnal cortisol patterns moderated the course of internalizing and externalizing symptoms from preschool to early adolescence. 554 children (54% male) and parents participated in a longitudinal study. Parents reported on their children's internalizing and externalizing symptoms at ages 3 and 12, and children collected diurnal saliva samples at age 9. Results showed that a steeper cortisol decline at age 9 combined with high internalizing or externalizing problems at age 3 predicted higher internalizing problems at age 12. A more blunted cortisol decline combined with early internalizing or externalizing problems predicted higher externalizing problems in early adolescence. These results illustrate the moderating role of stress system functioning in homotypic and heterotypic patterns of psychopathology from preschool to early adolescence.

The Role of the Lateral Hypothalamus in Violent Intraspecific Aggression-The Glucocorticoid Deficit Hypothesis

This review argues for a central role of the lateral hypothalamus in those deviant forms of aggression, which result from chronic glucocorticoid deficiency. Currently, this nucleus is considered a key region of the mechanisms that control predatory aggression. However, recent findings demonstrate that it is strongly activated by aggression in subjects with a chronically downregulated hypothalamus-pituitary-adrenocortical (HPA) axis; moreover, this activation is causally involved in the emergence of violent aggression. The review has two parts. In the first part, we review human findings demonstrating that under certain conditions, strong stressors downregulate the HPA-axis on the long run, and that the resulting glucocorticoid deficiency is associated with violent aggression including aggressive delinquency and aggression-related psychopathologies. The second part addresses neural mechanisms in animals. We show that the experimental downregulation of HPA-axis function elicits violent aggression in rodents, and the activation of the brain circuitry that originally subserves predatory aggression accompanies this change. The lateral hypothalamus is not only an integral part of this circuitry, but can elicit deviant and violent forms of aggression. Finally, we formulate a hypothesis on the pathway that connects unfavorable social conditions to violent aggression via the neural circuitry that includes the lateral hypothalamus.

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.

Implications of the Research Domain Criteria project for childhood anxiety and its disorders

Anxiety disorders are among the most prevalent psychiatric disorders in youth; however, progress in treatment for childhood anxiety has stalled over the past decade. The National Institute of Mental Health (NIMH) Research Domain Criteria (RDoC) project represents a shift toward a dimensional and interdisciplinary approach to psychiatric disorders; this shift can reframe developmental psychopathology for childhood anxiety and facilitate novel advances in its classification and treatment. Here we highlight constructs in the Systems for Social Processes and the Negative Valence System domains of RDoC, as they relate to childhood anxiety disorders. Childhood anxiety relates to both RDoC domains. In terms of social processes, through natural reliance on parents to reduce children's fear, attachment represents one particular social process, which plays a central role in anxiety among youth. In terms of negative valence, considerable research links threat conditioning to pediatric anxiety. Finally, fronto-amygdala circuitry relates to all three entities, as it has been shown to underly both attachment processes and threat learning, while it also has been consistently implicated in anxiety disorders across development. Through integrative and translational approaches, RDoC provides unique opportunities and simultaneous challenges for advancing the understanding and treatment of childhood anxiety disorders.

Cognitive control moderates parenting stress effects on children's diurnal cortisol

This study investigated associations between parenting stress in parents and self-reported stress in children with children's diurnal cortisol secretion and whether these associations are moderated by known stress-regulating capacities, namely child cognitive control. Salivary cortisol concentrations were assessed from awakening to evening on two weekend days from 53 6-to-7-year-old children. Children completed a cognitive control task and a self-report stress questionnaire with an experimenter, while parents completed a parenting stress inventory. Hierarchical, linear mixed effects models revealed that higher parenting stress was associated with overall reduced cortisol secretion in children, and this effect was moderated by cognitive control. Specifically, parenting stress was associated with reduced diurnal cortisol levels in children with lower cognitive control ability and not in children with higher cognitive control ability. There were no effects of self-reported stress in children on their cortisol secretion, presumably because 6-to-7-year-old children cannot yet self-report on stress experiences. Our results suggest that higher cognitive control skills may buffer the effects of parenting stress in parents on their children's stress regulation in middle childhood. This could indicate that training cognitive control skills in early life could be a target to prevent stress-related disorders.

Salivary Cortisol Profiles of Children with Hearing Loss

OBJECTIVES

It has long been speculated that effortful listening places children with hearing loss at risk for fatigue. School-age children with hearing loss experiencing cumulative stress and listening fatigue on a daily basis might undergo dysregulation of hypothalamic-pituitary-adrenal (HPA) axis activity resulting in elevated or flattened cortisol profiles. The purpose of this study was to examine whether school-age children with hearing loss show different diurnal salivary cortisol patterns than children with normal hearing.

DESIGN

Participants included 32 children with mild to moderate hearing loss (14 males; 18 females) and 28 children with normal hearing (19 males; 9 females) ranging in age from 6 to 12 years. Saliva samples were obtained six times per day on two separate school days. Cortisol levels were measured by mass spectrometric detection after liquid-liquid extraction. Salivary cortisol levels between children with hearing loss and children with no hearing loss over the course of the day were examined with hierarchical linear modeling using mixed model statistical analysis. Between-group comparisons were also computed for the area under the curve, an analytical approach for calculating overall cortisol secretion throughout the day.

RESULTS

Significant differences in the cortisol awakening response (CAR) were observed between children with hearing loss and children with normal hearing; however, no differences were observed between the two groups subsequent to the cortisol awakening response (60-min postawakening, 10:00 A.M., 2:00 P.M., and 8:00 P.M.). Compared with children with normal hearing, children with hearing loss displayed elevated cortisol levels at awakening and a reduced growth in cortisol secretion from awakening to 30-min postawakening. No significant differences in overall cortisol secretion throughout the day were found between groups (area under the curve). Finally, cortisol levels increased with increasing age for children with hearing loss but not for children with normal hearing.

CONCLUSIONS

Results of this preliminary study indicate a possible dysregulation in HPA axis activity in children with hearing loss characterized by elevated salivary cortisol levels at awakening and a diminished increase in cortisol from awakening to 30-min postawakening. The pattern of elevated cortisol levels at awakening is consistent with some studies on adults with burnout, a condition characterized by fatigue, loss of energy, and poor coping skills. These findings support the idea that children with hearing loss may experience increased vigilance and need to mobilize energy promptly in preparation for the new day.

Classroom social experiences in early elementary school relate to diurnal cortisol levels

Social stress has been linked to altered hypothalamic-pituitary-adrenocorticol (HPA) axis activation. During elementary school, children can become exposed to negative peer relations, such as poor appraisal among classroom peers, which is considered a social stressor. However, little is known about the association between classroom peer appraisal and the physiological stress system in children. The goal of this study was to examine the association of peer acceptance and peer non-acceptance with diurnal cortisol concentrations in 222 children from 20 mainstream elementary schools (Mage=6.97years, SD=0.99, 55% boys) in the Netherlands. Saliva samples were collected at awakening, 30min post-awakening, at noon and at 8 pm during a weekend day. From these assessments, the Cortisol Awakening Response (CAR), diurnal cortisol concentration (AUC_g) and diurnal cortisol slope were calculated. Peer nominations of peer acceptance (being liked), and peer non-acceptance (being disliked) were collected across a one year interval. Associations were controlled for peer victimization, age, sex and SES and children's levels of emotional problems and behavioural problems. Results showed that low peer acceptance was associated with heightened diurnal cortisol concentration (i.e., heightened AUG_g), lower cortisol reductions across the day (i.e., less decreasing cortisol slope) and heightened cortisol awakening response (i.e., heightened CAR). Peer non-acceptance and the interaction between peer acceptance and peer non-acceptance (known as peer rejection) were not associated with AUCg, cortisol slope or the CAR. The findings emphasize the association between poor appraisal among classroom peers and children's heightened HPA-axis activation. This underscores the importance of the physiological stress system in studying the consequences of negative peer relations in children.

HPA axis dysregulation in adult adoptees twenty years after severe institutional deprivation in childhood

Hypothalamic-pituitary-adrenal (HPA) axis function is disrupted in institutionally-deprived children - reduced morning cortisol, flattened diurnal slope and blunted reactivity persist even after successful adoption into positive family environments. Here we test whether such effects persist into adulthood. Cortisol release across the day (sampled at awakening, 30 and 45min later, and at four points across the day) was investigated in young adult adoptees who had lived in severe deprivation for up to 43 months in early childhood in Ceaușescu's Romanian orphanages and a comparison group of non-deprived UK adoptees (Total N=57; mean age=24±0.9years). The mediating role of cortisol levels on adult mental health was examined using data from standardized clinical assessments. Cortisol profiles were disrupted in the Romanian adoptees who experienced more than 6 months deprivation marked by a striking absence of the cortisol awakening response (CAR) and a significantly flatter cortisol curve until 1h 15min after awakening. Whereas institutional deprivation was associated with both cortisol secretion and emergence of emotional problems in young adulthood, path analysis revealed no evidence for a mediating role of CAR disruption in the sub-sample studied here. The results are in line with findings of HPA axis hypo-functionality following early adverse experience and provide strong evidence for long-term programming effects of HPA axis function through experience of institutional deprivation.

Shaping long-term primate development: Telomere length trajectory as an indicator of early maternal maltreatment and predictor of future physiologic regulation

The molecular, neurobiological, and physical health impacts of child maltreatment are well established, yet mechanistic pathways remain inadequately defined. Telomere length (TL) decline is an emerging molecular indicator of stress exposure with definitive links to negative health outcomes in maltreated individuals. The multiple confounders endemic to human maltreatment research impede the identification of causal pathways. This study leverages a unique randomized, cross-foster, study design in a naturalistic translational nonhuman primate model of infant maltreatment. At birth, newborn macaques were randomly assigned to either a maltreating or a competent control mother, balancing for sex, biological mother parenting history, and social rank. Offspring TL was measured longitudinally across the first 6 months of life (infancy) from peripheral blood. Hair cortisol accumulation was also determined at 6, 12, and 18 months of age. TL decline was greater in animals randomized to maltreatment, but also interacted with biological mother group. Shorter TL at 6 months was associated with higher mean cortisol levels through 18 months (juvenile period) when controlling for relevant covariates. These results suggest that even under the equivalent social, nutritional, and environmental conditions feasible in naturalistic translational nonhuman primate models, early adverse caregiving results in lasting molecular scars that foreshadow elevated health risk and physiologic dysregulation.