Low salivary cortisol levels and externalizing behavior problems in youth

Prenatal stress and child externalizing behavior: effects of maternal perceived stress and cortisol are moderated by child sex

BACKGROUND

Externalizing behavior problems are related to social maladjustment. Evidence indicates associations between prenatal stress and child behavioral outcomes. It remains unclear how psychological distress vs. biological correlates of stress (cortisol) differentially predict externalizing behavior, and how their effects might differ as a function of child sex.

METHOD

108 pregnant women from the community collected salivary cortisol and reported their perceived stress during each trimester of pregnancy. At child age 9 years (M = 9.01, SD = 0.55), 70 mothers and children reported on child behavior. Structural equation modelling was used to analyze how cortisol levels and perceived stress during pregnancy predicted current child externalizing behavior, considering the moderating effect of child sex.

RESULTS

Perceived stress predicted higher externalizing behavior in boys (β = 0.42, p = 0.009) and lower externalizing behavior in girls (β = - 0.56, p = 0.014). Cortisol predicted lower externalizing behavior in boys (β = - 0.81, p < .001) and was not related to girls' externalizing behavior (β = 0.37, p = 0.200).

DISCUSSION/CONCLUSION

Prenatal stress affected externalizing behavior differently in girls vs. boys. These response patters in turn differed for indicators of psychological vs. biological maternal stress, encouraging an integrated approach. Findings indicate that perceived stress and cortisol may affect child development via different trajectories.

Associations Between Children's Telomere Length, Parental Intrusiveness, and the Development of Early Externalizing Behaviors

Shorter telomeres mark cellular aging and are linked to chronic stress exposure as well as negative physical and psychological outcomes. However, it is unclear whether telomere length mediates associations between early stress exposure and later externalizing problems, or whether boys and girls differ in pathways to these concerns. We therefore examined associations between telomere length, early stress via negative caregiving, and children's externalizing symptom development over time in 409 three-year-old children and their parents. Telomere length mediated the association between early parental intrusiveness and later rule-breaking behavior; however, this association was moderated by children's biological sex such that parent intrusiveness was related only to boys' rule-breaking. Findings support the notion that children's telomere length may mark individual differences in responses to negative early caregiving, and highlight a potential mechanism contributing to the development of rule-breaking problems in boys.

Individual differences in social homeostasis

The concept of “social homeostasis”, introduced by Matthews and Tye in 2019, has provided a framework with which to consider our changing individual needs for social interaction, and the neurobiology underlying this system. This model was conceived as including detector systems, a control center with a setpoint, and effectors which allow us to seek out or avoid additional social contact. In this article, we review and theorize about the many different factors that might contribute to the setpoint of a person or animal, including individual, social, cultural, and other environmental factors. We conclude with a consideration of the empirical challenges of this exciting new model.

DHEAS and nutritional status among Sidama, Ngandu, and Aka children: Effects of cortisol and implications for adrenarche

OBJECTIVE

Adrenarche, the biological event marked by rising production of dehydroepiandrosterone and its sulfate (DHEAS), may represent a sensitive period in child development, with important implications for adolescence and beyond. Nutritional status, particularly BMI and/or adiposity, has long been hypothesized as a factor in DHEAS production but findings are inconsistent, and few studies have examined this among non-industrialized societies. In addition, cortisol has not been included in these models. We here evaluate effects of height- (HAZ), weight- (WAZ), and BMI- (BMIZ) for-age on DHEAS concentrations among Sidama agropastoralist, Ngandu horticulturalist, and Aka hunter-gatherer children.

METHODS

Heights and weights were collected from 206 children aged 2-18 years old. HAZ, WAZ, and BMIZ were calculated using CDC standards. DHEAS and cortisol assays were used to determine biomarker concentrations in hair. Generalized linear modeling was used to examine effects of nutritional status on DHEAS concentrations, as well as cortisol, controlling for age, sex, and population.

RESULTS

Despite the prevalence of low HAZ and WAZ scores, the majority (77%) of children had BMI z-scores >-2.0 SD. Nutritional status has no significant effect on DHEAS concentrations, controlling for age, sex, and population. Cortisol, however, is a significant predictor of DHEAS concentrations.

CONCLUSIONS

Our findings do not support a relationship between nutritional status and DHEAS. Instead, results suggest an important role for stress and ecology in DHEAS concentrations across childhood. Specifically, effects of environment via cortisol may be influential to patterning of DHEAS. Future work should investigate local ecological stressors and their relationship to adrenarche.

Circadian cortisol secretion in adolescent girls with conduct disorder

Severe antisocial behavior in girls, best exemplified by conduct disorder (CD), is a serious clinical and public health problem. Treatment is difficult, particularly in girls with comorbid internalizing disorders. Identifying biological correlates may help to develop new treatments or diagnostic, prognostic, or treatment response biomarkers. Based on our earlier work and research from others occurring primarily in boys with severe antisocial behavior, it is possible that abnormalities in the hypothalamic pituitary adrenal (HPA) axis circadian cortisol cycle may be associated with female CD. Additionally, research suggests that the presence of comorbid internalizing disorders may be related to differences in cortisol secretion, compared to subjects who only have CD. Our study aimed: 1) to compare the circadian cortisol cycle in 98 girls with CD, 15-16 years of age to 47 girls without any psychiatric disorder (ND) and 2) to compare the cycle in girls with CD and comorbid internalizing disorders (CD + INT) to those without such comorbidity (CD Only). Salivary cortisol was collected over 24 h during weekdays at scheduled times, with protocol adherence measures in place. Unstructured covariance pattern modeling, controlling for effects of age, social class, IQ, and awakening time was used to analyze cortisol data. CD was associated with overall lower cortisol secretion (p = 0.03), but this difference was due to a lower volume of cortisol secreted 30 min after awakening (area under the curve with respect to ground, p = 0.01). Circadian cortisol secretion was no different in the CD+INT group compared to the CD Only group (p = 0.52). Our findings need to be replicated using current consensus guidelines for the assessment of the CAR. We also suggest two new avenues of research in this field.

Links between Oppositional Defiant Disorder Dimensions, Psychophysiology, and Interpersonal versus Non-interpersonal Trauma

The etiology of oppositional defiant disorder (ODD) is not well understood but appears to have both biologically-based roots and can develop following adverse experiences. The current study is the first to examine the interaction between biologically-based factors and type of trauma experience (i.e., interpersonal and non-interpersonal) and associations with ODD. The psychophysiological factors included baseline resting heart rate, respiratory sinus arrhythmia (RSA), and cortisol. ODD was measured as two dimensions of irritable and defiant/vindictive. The sample included 330 children, 3-7 years-old, oversampled for a history of trauma. Results showed the interactions between baseline physiological arousal variables and trauma type in predicting ODD dimensions were not supported. However, the baseline RSA by trauma interaction was a significant predictor of defiance/vindictiveness among boys, but not girls, when interpersonal trauma was compared to controls. Several other gender differences emerged. Among boys, both interpersonal and non-interpersonal trauma were predictive of ODD dimensions; however, among girls, non-interpersonal trauma was not. Among girls, there was a significant negative bivariate relationship between baseline cortisol and irritability. Also, when the sample was restricted to those with interpersonal trauma only and controls, baseline RSA was negatively associated with irritability in girls only (controlling for trauma). Finally, retrospective reports revealed that children who met criteria for ODD diagnosis and experienced interpersonal trauma were more likely to exhibit ODD symptoms prior to their trauma compared to those who experienced non-interpersonal trauma. Results are discussed in the context of previous mixed findings, and avenues for future research are highlighted.

Mother and child hair cortisol during the COVID-19 pandemic: Associations among physiological stress, pandemic-related behaviors, and child emotional-behavioral health

The current study assessed the associations between pandemic-related stressors and physiological stress, as indexed by hair cortisol concentration (HCC), for mothers and their children (N = 180) aged 5-14-years old (M = 8.91). The associations between maternal HCC and children's HCC and children's behavioral adjustment were also examined. Mothers reported on COVID-19-related behaviors and children's adjustment, and both mother and child participants collected and mailed hair samples between August and November of 2020. Results indicated that higher maternal HCC was correlated with living in a more urban environment, job loss, working from home, exposure to pandemic-related news, and social isolation. Child HCC was correlated with family job loss and social isolation. Mother HCC and child HCC were significantly associated, and this association was moderated by child age; younger children's HCC was more strongly associated with mothers' HCC than older children's HCC. Finally, maternal HCC was associated with greater child internalizing symptoms, but was not associated with children's externalizing symptoms. Child HCC was not associated with child behavior.

Consequences of Prematurity on Cortisol Regulation and Adjustment Difficulties: A 9-Year Longitudinal Study

A preterm birth represents a stressful event having potentially negative long-term consequences. Thirty-three children born preterm (<33 weeks gestational age) and eleven full-term children participated in a nine-year longitudinal study. Perinatal Risk Inventory (PERI) was used at birth to assess the perinatal stress. Salivary cortisol, collected four times a day over two consecutive days, was measured with radioimmunoassay technique at six months and nine years to assess the hypothalamic-pituitary-adrenal (HPA) axis. Mothers reported post-traumatic symptoms on a self-report questionnaire 12 months after their child's birth and children's adjustment problems at 9 years of child age on the Child Behavior Checklist. Results showed a significant difference in cortisol regulation at nine years between preterm and full-term children but no differences in adjustment problems. Whereas biological factors (i.e., PERI, cortisol regulation at six months) explained cortisol at nine years, maternal post-traumatic symptoms were predictive of adjustment problems in their child. In conclusion, very preterm birth has some long-term consequences on the HPA-axis regulation at nine years. Although cortisol regulation is mostly influenced by biological factors, the presence of maternal post-traumatic symptoms predicts the manifestation of adjustment problems in both groups. This shows the importance of maternal psychological well-being for child development. Further research is needed to understand the exact consequences of premature birth on cortisol regulation and the implication for the child's development and health.

Patterns of poverty across adolescence predict salivary cortisol stress responses in Mexican-origin youths

Poverty is a chronic stressor associated with disruptions in psychophysiological development during adolescence. This study examined associations of chronic poverty and income changes experienced from pre- to mid-adolescence with hypothalamic-pituitary-adrenal (HPA) axis stress responses in late adolescence. Participants (N = 229) were adolescents of Mexican-origin (48.7% female). Household income (converted to income-to-needs ratios) was assessed annually when children were 10-16 years old. At 17 years, adolescents completed Cyberball, a social exclusion simulation task while undergoing a functional magnetic resonance imaging scan. Saliva samples were collected prior to and five times over a 50-minute period following the scan, from which salivary cortisol was assayed. Results showed that differential trajectories of poverty from ages 10-16 predicted HPA axis activity at age 17. Relative to others, distinct HPA suppression (hyporeactivity) was demonstrated by youth who started adolescence in deep poverty and were still living in poverty at age 16 despite experiencing some income gains. Youth from more economically secure families evinced typical cortisol increases following the lab stressor. These results suggest that subsequent HPA functioning varies as a function of economic status throughout adolescence, and that efforts to increase family income may promote healthy HPA functioning for youths in the most impoverished circumstances.

Cortisol Reactivity as a Mediator of Peer Victimization on Child Internalizing and Externalizing Problems: The Role of Gender Differences

Children exposed to peer victimization are at increased risk for psychopathology. However, the physiological mechanisms linking peer victimization to child psychopathology and the potential gender differences in these links remain inadequately understood. The present study examined whether cortisol reactivity to acute stress mediated the associations between relational and physical victimization and internalizing and externalizing problems and whether these associations differed between boys and girls. A sample of 150 Chinese children (aged 9-13 years; M_age = 10.69 years; 51% boys) reported experiences of relational and physical victimization and participated in a standardized laboratory psychosocial stress task, during which six salivary cortisol samples were collected. Parents or primary caregivers reported their children's internalizing and externalizing problems. Overall, neither physical nor relational victimization was associated with cortisol reactivity. However, when examined separately by gender, relational victimization was associated with blunted cortisol reactivity for boys but not for girls. Further, among boys but not girls, relational victimization was indirectly associated with internalizing and externalizing problems via blunted cortisol reactivity. Our findings suggest that blunted cortisol reactivity may serve as a physiological pathway linking peer victimization to psychopathology for boys but not for girls.

Hypothalamic-Pituitary-Adrenal Axis Activity in Childhood Predicts Emotional Memory Effects and Related Neural Circuitry in Adolescent Girls

Negative emotional experiences can be more difficult to forget than neutral ones, a phenomenon termed the "emotional memory effect." Individual differences in the strength of the emotional memory effect are associated with emotional health. Thus, understanding the neurobiological underpinnings of the emotional memory effect has important implications, especially for individuals at risk for emotional health problems. Although the neural basis of emotional memory effects has been relatively well defined, less is known about how hormonal factors that can modulate emotional memory, such as glucocorticoids, relate to that neural basis. Importantly, probing the role of glucocorticoids in the stress- and emotion-sensitive period of late childhood to adolescence could provide actionable points of intervention. We addressed this gap by testing whether hypothalamic-pituitary-adrenal (HPA) axis activity during a parent-child conflict task at 11 years of age predicted emotional memory and its primary neural circuitry (i.e., amygdala-hippocampus functional connectivity) at 16 years of age in a longitudinal study of 147 girls (104 with complete data). Results showed that lower HPA axis activity predicted stronger emotional memory effects, r(124) = -.236, p < .01, and higher emotional memory-related functional connectivity between the right hippocampus and the right amygdala, β = -.385, p < .001. These findings suggest that late childhood HPA axis activity may modulate the neural circuitry of emotional memory effects in adolescence, which may confer a potential risk trajectory for emotional health among girls.

Developmental pathways from preschool irritability to multifinality in early adolescence: the role of diurnal cortisol

BACKGROUND

Early irritability predicts a broad spectrum of psychopathology spanning both internalizing and externalizing disorders, rather than any particular disorder or group of disorders (i.e. multifinality). Very few studies, however, have examined the developmental mechanisms by which it leads to such phenotypically diverse outcomes. We examined whether variation in the diurnal pattern of cortisol moderates developmental pathways between preschool irritability and the subsequent emergence of internalizing and externalizing symptoms 9 years later.

METHOD

When children were 3 years old, mothers were interviewed about children's irritability and completed questionnaires about their children's psychopathology. Six years later, children collected saliva samples at wake-up and bedtime on three consecutive days. Diurnal cortisol patterns were modeled as latent difference scores between evening and morning samples. When children were approximately 12 years old, mothers again completed questionnaires about their children's psychopathology.

RESULTS

Among children with higher levels of irritability at age 3, a steeper diurnal cortisol slope at age 9 predicted greater internalizing symptoms and irritability at age 12, whereas a blunted slope at age 9 predicted greater externalizing symptoms at age 12, adjusting for baseline and concurrent symptoms.

CONCLUSION

Our results suggest that variation in stress system functioning can predict and differentiate developmental trajectories of early irritability that are relatively more internalizing v. those in which externalizing symptoms dominate in pre-adolescence.

Attention-Deficit/Hyperactivity Disorder Among US Children and Adolescents With Congenital Adrenal Hyperplasia

BACKGROUND

Little is known regarding risk for co-occurring mental health conditions among pediatric patients with congenital adrenal hyperplasia (CAH). The objective of the current study was to investigate the prevalence of medically managed attention-deficit/hyperactivity disorder (ADHD) in 2 large administrative samples of insured children and adolescents with and without CAH in the United States.

METHODS

We assessed the prevalence of CAH and of medically managed ADHD using algorithms defined from diagnosis codes and filled prescriptions data using the IBM MarketScan Commercial and Multi-State Medicaid claims databases. We evaluated subjects who were continuously enrolled for ≥ 12 months with a first claim during October 2015 through December 2017 when they were 5 to 18 years old.

RESULTS

The administrative prevalence of CAH in the Commercial (N = 3 685 127) and Medicaid (N = 3 434 472) samples was 10.1 per 100 000 (n = 372) and 7.2 per 100 000 (n = 247), respectively. The prevalence of medically managed ADHD in the non-CAH population was 8.4% in the Commercial sample and 15.1% in the Medicaid sample. Among children with CAH, there was no increased prevalence of ADHD in the Commercial (9.2%, prevalence ratio [PR] = 1.1; 95% confidence interval [CI], 0.82-1.54; P = 0.48) or Medicaid (13.8%; PR = 0.91; 95% CI, 0.67-1.24; P = 0.55) samples compared with the general population.

CONCLUSIONS

Using 2 large samples of insured children and adolescents in the United States, we found similar prevalence of medically managed ADHD among those with CAH and the general population. Future research to assess the validity of our claims algorithm for identifying pediatric CAH cases is warranted.

Patterns of urinary cortisol levels during ontogeny appear population specific rather than species specific in wild chimpanzees and bonobos

Compared with most mammals, postnatal development in great apes is protracted, presenting both an extended period of phenotypic plasticity to environmental conditions and the potential for sustained mother-offspring and/or sibling conflict over resources. Comparisons of cortisol levels during ontogeny can reveal physiological plasticity to species or population specific socioecological factors and in turn how these factors might ameliorate or exaggerate mother-offspring and sibling conflict. Here, we examine developmental patterns of cortisol levels in two wild chimpanzee populations (Budongo and Taï), with two and three communities each, and one wild bonobo population (LuiKotale), with two communities. Both species have similar juvenile life histories. Nonetheless, we predicted that key differences in socioecological factors, such as feeding competition, would lead to interspecific variation in mother-offspring and sibling conflict and thus variation in ontogenetic cortisol patterns. We measured urinary cortisol levels in 1394 samples collected from 37 bonobos and 100 chimpanzees aged up to 12 years. The significant differences in age-related variation in cortisol levels appeared population specific rather than species specific. Both bonobos and Taï chimpanzees had comparatively stable and gradually increasing cortisol levels throughout development; Budongo chimpanzees experienced declining cortisol levels before increases in later ontogeny. These age-related population differences in cortisol patterns were not explained by mother-offspring or sibling conflict specifically; instead, the comparatively stable cortisol patterns of bonobos and Taï chimpanzees likely reflect a consistency in experience of competition and the social environment compared with Budongo chimpanzees, where mothers may adopt more variable strategies related to infanticide risk and resource availability. The clear population-level differences within chimpanzees highlight potential intraspecific flexibility in developmental processes in apes, suggesting the flexibility and diversity in rearing strategies seen in humans may have a deep evolutionary history.

Culture and stress biology in immigrant youth from the prenatal period to adolescence: A systematic review

Immigration patterns over the last two decades have changed the demographic composition of the United States; children are growing up in an increasingly multicultural environment. Immigrant youth may face culture-related stressors and leverage culture-related strengths across development that may influence their mental and physical health. Responses to early life stressors may differ across children at the level of stress biology, which can affect how they handle cultural challenges. However, there is limited research on culture and stress biology, which may be a mediator or moderator of culture's effects on immigrant youth. The aim of the present article is to systematically review research that examines the roles of both culture and stress biology from the prenatal period to adolescence in immigrant youth. Specifically, we review articles that examine how stress-sensitive biological systems (hypothalamic pituitary adrenal axis and the autonomic nervous system) and culture-related constructs have been modeled together in immigrant youth. Based on these findings, we note remaining questions and recommendations for future research in integrating measures of cultural processes and stress biology in children.

Interparental conflict as a curvilinear risk factor of youth emotional and cortisol reactivity

This study examined interparental conflict as a linear and curvilinear predictor of subsequent changes in adolescents' negative emotional reactivity and cortisol functioning during family conflict and, in turn, their psychological difficulties. In addition, adolescents' negative emotional reactivity and cortisol functioning during family conflict were examined as subsequent predictors of their psychological difficulties. Participants included 258 adolescents (52% girls) and their parents and teachers who participated in 3 annual measurement occasions. Adolescents were 13 years old on average (standard deviation [SD] = .57) at the first measurement occasion, were generally from middle- and working-class backgrounds, and identified mostly as White (e.g., 74%). The results of latent-difference score analyses indicated that a multimethod and multiinformant assessment of interparental conflict linearly predicted subsequent changes in observational ratings of adolescent emotional reactivity and their overall cortisol output in response to family conflict over a 1-year period. These changes, in turn, predicted increases in multiinformant reports of adolescent psychological problems over a 2-year period. However, the linear association in the first link in the cascade was qualified by the quadratic effects of interparental conflict as a predictor. Consistent with risk-saturation models, the relatively strong associations among interparental conflict and youth emotional reactivity and cortisol output at mild and moderate exposure to conflict weakened as exposure to conflict reached higher levels. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

The Interaction Between Physical and Psychosocial Stressors

Do physical and psychosocial stressors interact to increase stress in ways not explainable by the stressors alone? A preliminary study compared participants' stress response while subjected to a physical stressor (reduced or full physical load) and a predetermined social stressor (confronted by calm or aggressive behavior). Salivary cortisol samples measured endocrine stress. Heart rate variability (HRV) and electrodermal activity (EDA) measured autonomic stress. Perceived stress was measured via discomfort and stress state surveys. Participants with a heavier load reported increased distress and discomfort. Encountering an aggressive individual increased endocrine stress, distress levels, and perceived discomfort. Higher autonomic stress and discomfort were found in participants with heavier physical load and aggressive individuals. The results suggest a relationship where physical load increases the stressfulness of aggressive behavior in ways not explainable by the effects of the stressors alone. Future research is needed to confirm this investigation's findings.

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.

Day-to-day friends' victimization, aggression perpetration, and morning cortisol activity in late adolescents

This study investigates bidirectional associations between adolescents' daily experiences of victimization and aggression perpetration within friendships. We investigated (a) across-day associations between victimization and aggression perpetration; (b) morning cortisol activity as a moderator of cross-day victimization and aggression links; and (c) potential sex differences in these patterns. For 4 consecutive days, 99 adolescents (Mage  = 18.06, SD = 1.09, 46 females) reported whether they were victimized by or aggressive toward their friends. On three of these days, adolescents provided three morning saliva samples. Multilevel path analyses showed that across days, victimization and aggression were bidirectionally linked, but only for male adolescents. Additionally, for male adolescents, morning cortisol output (but not morning cortisol increase) moderated the association between victimization and next-day aggression; victimization predicted greater next-day aggression for boys with low, but not high, morning cortisol output. Findings implicate a physiological factor that may modify daily links between victimization and aggression in male adolescent friendships.

Parental depression moderates the relationships of cortisol and testosterone with children's symptoms

BACKGROUND

Previous research on the hormone-symptom relationship in children suggests that certain hormone patterns may be associated with symptoms, but only under certain circumstances. Having a parent with a history of depression may be one circumstance under which dysregulated hormone patterns are especially associated with emotional and behavioral symptoms in children. The current study sought to explore these relationships in a community sample of 389 9-year-old children.

METHODS

Children's salivary cortisol and testosterone levels were collected at home over three consecutive days; parental psychiatric histories were assessed using semi-structured diagnostic interviews; and children's internalizing and externalizing symptoms were rated by the child's mother.

RESULTS

Having two parents with a history of depression moderated the associations of reduced total daily cortisol output with higher externalizing scores, as well as the association of reduced testosterone with higher internalizing scores. A maternal history of depression, on the other hand, moderated the relationship between higher cortisol awakening response and higher internalizing scores. Furthermore, lower daily cortisol output was associated with higher internalizing scores among girls, but not boys, with two parents with a history depression.

LIMITATIONS

Limitations include the cross-sectional nature of the current analyses, as well as the limited racial, ethnic, and geographical diversity of the sample.

CONCLUSIONS

Taken together, the current results suggest that the relationship between hormones and internalizing and externalizing symptoms in children may vary as a function of parental depression and child sex, knowledge that may inform intervention efforts aimed at preventing psychopathology in children whose parents have a history of depression.

Depression, violence and cortisol awakening response: a 3-year longitudinal study in adolescents

BACKGROUND

Despite evidence of links between depression and violent outcomes, potential moderators of this association remain unknown. The current study tested whether a biological marker, cortisol, moderated this association in a longitudinal sample of adolescents.

METHODS

Participants were 358 Dutch adolescents (205 boys) with a mean age of 15 years at the first measurement. Depressive symptoms, the cortisol awakening response (CAR) and violent outcomes were measured annually across 3 years. The CAR was assessed by two measures: waking cortisol activity (CAR area under the curve ground) and waking cortisol reactivity (CAR area under the curve increase). Within-individual regression models were adopted to test the interaction effects between depressive symptoms and CAR on violent outcomes, which accounted for all time-invariant factors such as genetic factors and early environments. We additionally adjusted for time-varying factors including alcohol drinking, substance use and stressful life events.

RESULTS

In this community sample, 24% of adolescents perpetrated violent behaviours over 3 years. We found that CAR moderated the effects of depressive symptoms on adolescent violent outcomes (βs ranged from -0.12 to -0.28). In particular, when the CAR was low, depressive symptoms were positively associated with violent outcomes in within-individual models, whereas the associations were reversed when the CAR was high.

CONCLUSIONS

Our findings suggest that the CAR should be investigated further as a potential biological marker for violence in adolescents with high levels of depressive symptoms.

Early-life adversity-induced long-term epigenetic programming associated with early onset of chronic physical aggression: Studies in humans and animals

Objectives: To examine whether chronic physical aggression (CPA) in adulthood can be epigenetically programmed early in life due to exposure to early-life adversity. Methods: Literature search of public databases such as PubMed/MEDLINE and Scopus. Results: Children/adolescents susceptible for CPA and exposed to early-life abuse fail to efficiently cope with stress that in turn results in the development of CPA later in life. This phenomenon was observed in humans and animal models of aggression. The susceptibility to aggression is a complex trait that is regulated by the interaction between environmental and genetic factors. Epigenetic mechanisms mediate this interaction. Subjects exposed to stress early in life exhibited long-term epigenetic programming that can influence their behaviour in adulthood. This programming affects expression of many genes not only in the brain but also in other systems such as neuroendocrine and immune. Conclusions: The propensity to adult CPA behaviour in subjects experienced to early-life adversity is mediated by epigenetic programming that involves long-term systemic epigenetic alterations in a whole genome.

Maternal Postpartum Depression Increases Vulnerability for Toddler Behavior Problems through Infant Cortisol Reactivity

The current study examined the role of hypothalamic-pituitary-adrenal reactivity (a physiological indicator of stress) in early infancy as a mediator of the relationship between maternal postpartum depression and toddler behavior problems. Participants were 137 at-risk mothers and their children participating in a longitudinal study of intergenerational transmission of risk. Mothers' depression was measured five times during the infants' first 18 months. Infant cortisol was collected during a social stressor (the still-face paradigm) when infants were 6 months old, and mothers reported on toddlers' internalizing and externalizing symptoms at 18 months. Among this sample of high-risk mother-infant dyads, early postpartum depression predicted atypical infant cortisol reactivity at 6 months, which mediated the effect of maternal depression on increased toddler behavior problems. Clinical implications are discussed.

Persistent Effects of Antenatal Synthetic Glucocorticoids on Endocrine Stress Reactivity From Childhood to Adolescence

CONTEXT

Antenatal synthetic glucocorticoid (sGC) therapy has been identified as a potent programming factor of the hypothalamic-pituitary-adrenal (HPA) axis. We previously observed significantly increased cortisol stress responses in 6- to 11-year-old, term-born children exposed to antenatal sGCs compared with controls. These findings call for longitudinal follow-up studies to evaluate long-term effects of antenatal sGCs, given that adolescence is marked by a substantial shift of HPA axis functioning.

OBJECTIVE

This study aimed to longitudinally investigate the stability of antenatal sGC-related effects on cortisol stress reactivity from childhood to adolescence.

DESIGN, SETTING, AND PARTICIPANTS

To evaluate long-term trajectories of antenatal sGCs, we longitudinally followed a subsample (n = 44) of our children's cohort into adolescence (14 to 18 years old) for a second assessment. To this end, 22 adolescents with antenatal sGC exposure and 22 untreated controls underwent a standardized laboratory stressor [Trier Social Stress Test (TSST)].

RESULTS

Besides a general increase in HPA axis reactivity from childhood to adolescence (P < 0.05), participants treated with antenatal sGCs showed significantly higher cortisol levels in response to the TSST compared with controls during both developmental stages (P < 0.05). Furthermore, we observed a moderating effect of sGCs on rank-order stability of cortisol stress reactivity from childhood to adolescence (P < 0.05) with a trend (P = 0.07) for higher rank-order stability in sGC-exposed individuals (r = 0.37) compared with controls (r = -0.20).

CONCLUSION

These findings suggest that antenatal sGCs yield long-term changes of HPA axis reactivity that persist into adolescence and may confer increased vulnerability for developing stress-related disorders.

Sex-specific contribution of DHEA-cortisol ratio to prefrontal-hippocampal structural development, cognitive abilities and personality traits

Although dehydroepiandrosterone (DHEA) may exert neuroprotective effects in the developing brain, prolonged or excessive elevations in cortisol may exert neurotoxic effects. The ratio between DHEA and cortisol (DC ratio) has been linked to internalising and externalising disorders, as well as cognitive performance, supporting the clinical relevance of this hormonal ratio during development. However, the brain mechanisms by which these effects may be mediated have not yet been identified. Furthermore, although there is evidence that the effects of cortisol in the central nervous system may be sexually dimorphic in humans, the opposite is true for DHEA, with human studies showing no sex-specific associations in cortical thickness, cortico-amygdalar or cortico-hippocampal structural covariance. Therefore, it remains unclear whether sex moderates the developmental associations between DC ratio, brain structure, cognition and behaviour. In the present study, we examined the associations between DC ratio, structural covariance of the hippocampus with whole-brain cortical thickness, and measures of personality, behaviour and cognition in a longitudinal sample of typically developing children, adolescents and young adults aged 6-22 years (N = 225 participants [F = 128]; 355 scans [F = 208]), using mixed effects models that accounted for both within- and between-subject variances. We found sex-specific interactions between DC ratio and anterior cingulate cortex-hippocampal structural covariance, with higher DC ratios being associated with a more negative covariance between these structures in girls, and a more positive covariance in boys. Furthermore, the negative prefrontal-hippocampal structural covariance found in girls was associated with higher verbal memory and mathematical ability, whereas the positive covariance found in boys was associated with lower cooperativeness and reward dependence personality traits. These findings support the notion that the ratio between DHEA and cortisol levels may contribute, at least in part, to the development of sex differences in cognitive abilities, as well as risk for internalising/externalising disorders, via an alteration in prefrontal-hippocampal structure during the transition from childhood to adulthood.

Child sex moderates the relationship between cortisol stress reactivity and symptoms over time

BACKGROUND

Past work suggests that individual differences in stress reactivity have implications for the development of psychopathology; in particular, females' stress reactivity appears more closely tied to internalizing symptoms than males' reactivity. Conversely, males who are under-reactive to threat may be at risk for externalizing problems. However, little is known about when such differences may emerge, although this knowledge could have implications for early prevention.

METHODS

Cortisol reactivity to a laboratory stressor was assessed in 409 three-year-old children (201 boys), along with parent-reported children's internalizing (anxiety and depression) and externalizing (oppositional-defiant and attention problems and hyperactivity) symptoms. Parent-reported symptoms were re-collected at child ages 5 (N = 379) and 8 (N = 364). Multilevel modelling was used to investigate whether the relationship between cortisol reactivity and symptoms differed between boys and girls over time.

RESULTS

Girls with lower cortisol reactivity showed a negative association between depressive symptoms and time, while girls with higher reactivity showed no such association. No interaction between sex and cortisol reactivity was found for anxious symptoms. Boys with higher cortisol reactivity showed a negative association between symptoms and time, while boys with lower cortisol reactivity showed no such association. Time and ADHD symptoms were unrelated for boys, regardless of their cortisol reactivity.

CONCLUSIONS

Findings suggest that the implications of stress reactivity indexed via cortisol vary for boys and girls, as well as for different symptom manifestations.

Children's stress regulation mediates the association between prenatal maternal mood and child executive functions for boys, but not girls

Prenatal exposure to maternal mood disturbances shapes children's cognitive development reflected in the critical construct of executive functions (EFs). Little is known, however, about underlying mechanisms. By examining cortisol responses in both everyday and lab challenge settings, we tested whether the child/offspring hypothalamic-pituitary-adrenal axis mediates effects of prenatal maternal mood on child EFs at age 6. In 107 Canadian children born to women with a wide range of anxious and depressive symptoms during pregnancy, we found that in boys but not girls, depressed and/or anxious prenatal maternal mood is associated with heightened diurnal cortisol levels in everyday settings, as well as heightened cortisol reactivity to a lab challenge and that this heightened reactivity was associated with poorer EFs. Among boys we also observed that cortisol reactivity but not diurnal cortisol mediated the association between depressed and/or anxious prenatal maternal mood and EFs. Depressed and/or anxious prenatal maternal mood was related to child EFs for both girls and boys. To our knowledge, this is the first study to demonstrate a mediating role for child stress regulation in the association between prenatal maternal stress-related mood disturbances and child EFs, providing evidence of a mechanism contributing to fetal programming of cognition.

The role of bicultural adaptation, familism, and family conflict in Mexican American adolescents' cortisol reactivity

Scarce research has examined stress responsivity among Latino youths, and no studies have focused on the role of acculturation in shaping cortisol stress response in this population. This study assessed Mexican American adolescents' Mexican and Anglo cultural orientations and examined prospective associations between their patterns of bicultural orientation and hypothalamic-pituitary-adrenal cortisol reactivity to an adapted Trier Social Stress Test. The sample included 264 youths from a longitudinal birth cohort study who completed the Trier Social Stress Test and provided saliva samples at age 14. The youths completed assessments of cultural orientation at age 12, and family conflict and familism at age 14. Analyses testing the interactive effects of Anglo and Mexican orientation showed significant associations with cortisol responsivity, including the reactivity slope, peak levels, and recovery, but these associations were not mediated by family conflict nor familism values. Findings revealed that bicultural youth (high on both Anglo and Mexican orientations) showed an expected pattern of high cortisol responsivity, which may be adaptive in the context of a strong acute stressor, whereas individuals endorsing only high levels of Anglo orientation had a blunted cortisol response. Findings are discussed in relation to research on biculturalism and the trade-offs and potential recalibration of a contextually responsive hypothalamic-pituitary-adrenal axis for acculturating adolescents.

Genes and Aggressive Behavior: Epigenetic Mechanisms Underlying Individual Susceptibility to Aversive Environments

Over the last two decades, the study of the relationship between nature and nurture in shaping human behavior has encountered a renewed interest. Behavioral genetics showed that distinct polymorphisms of genes that code for proteins that control neurotransmitter metabolic and synaptic function are associated with individual vulnerability to aversive experiences, such as stressful and traumatic life events, and may result in an increased risk of developing psychopathologies associated with violence. On the other hand, recent studies indicate that experiencing aversive events modulates gene expression by introducing stable changes to DNA without modifying its sequence, a mechanism known as “epigenetics”. For example, experiencing adversities during periods of maximal sensitivity to the environment, such as prenatal life, infancy and early adolescence, may introduce lasting epigenetic marks in genes that affect maturational processes in brain, thus favoring the emergence of dysfunctional behaviors, including exaggerate aggression in adulthood. The present review discusses data from recent research, both in humans and animals, concerning the epigenetic regulation of four genes belonging to the neuroendocrine, serotonergic and oxytocinergic pathways—Nuclear receptor subfamily 3-group C-member 1 (NR3C1), oxytocin receptor (OXTR), solute carrier-family 6 member 4 (SLC6A4) and monoamine oxidase A (MAOA)—and their role in modulating vulnerability to proactive and reactive aggressive behavior. Behavioral genetics and epigenetics are shedding a new light on the fine interaction between genes and environment, by providing a novel tool to understand the molecular events that underlie aggression. Overall, the findings from these studies carry important implications not only for neuroscience, but also for social sciences, including ethics, philosophy and law.

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.

Family conflict, chaos, and negative life events predict cortisol activity in low-income children

Childhood poverty is hypothesized to increase risk for mental and physical health problems at least in part through dysregulation of the hypothalamic-pituitary-adrenal axis. However, less is known about the specific psychosocial stressors associated with cortisol reactivity and regulation for children living in poverty. The current study investigates negative life events, household chaos, and family conflict in preschool and middle childhood as potential predictors of cortisol regulation in low-income 7-10 year olds (N = 242; M age = 7.9 years). Participants were assessed in preschool and participated in a follow-up assessment in middle childhood, during which diurnal free cortisol and free cortisol reactivity to the Trier Social Stress Test for Children (TSST-C) were assessed. Household chaos during preschool predicted a more blunted diurnal cortisol slope in middle childhood. Greater negative life events during preschool and greater concurrent family conflict were associated with increased free cortisol reactivity in middle childhood.

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.

A state-trait model of cortisol in early childhood: Contextual and parental predictors of stable and time-varying effects

This study examined state-trait models of diurnal cortisol (morning level and diurnal slope), and whether income, cumulative risk and parenting behaviors predicted variance in trait and state levels of cortisol. The sample of 306 mothers and their preschool children included 29% families at or near poverty, 27% families below the median income, and the remaining families at middle and upper income. Diurnal cortisol, income, cumulative risk, and parenting were measured at 4 time points, once every 9months, starting when children were 36-40months. State-trait models fit the data, suggesting significant state but not trait variance in cortisol. Low income and cumulative risk were related to trait levels of diurnal cortisol with little evidence of time-varying or state effects. Stable levels of parenting predicted trait levels of diurnal cortisol and time-varying levels of parenting predicted time-varying state levels of diurnal cortisol. Findings highlight the allostatic process of adaptation to risk as well as time-specific reactivity to variability in experience.

Glucocorticoid treatment earlier in childhood and adolescence show dose-response associations with diurnal cortisol levels

Heightened levels of glucocorticoids in children and adolescents have previously been linked to prolonged changes in the diurnal regulation of the stress-hormone cortisol, a glucocorticoid regulated by the hypothalamic-pituitary-adrenal-axis (HPA-axis). To address this question, we examined the salivary cortisol awakening response (CAR) and daily cortisol output in 36 children and adolescents (25 girls/11 boys) aged 7-16 years previously treated with glucocorticoids for nephrotic syndrome or rheumatic disorder and 36 healthy controls. Patients and controls did not significantly differ in the CAR or diurnal cortisol output; however, sex-dependent group differences were observed. Specifically, female patients had a higher CAR relative to female controls, while male patients had higher daily cortisol levels compared to male controls. Notably, CAR in female patients and daily cortisol levels in male patients showed a positive linear relationship with the mean daily glucocorticoid doses administered during treatment. The observed dose-response associations suggest that glucocorticoid therapy during childhood and adolescence might trigger long-term changes in HPA-axis regulation, which may differ for males and females.

Infant stranger fear trajectories predict anxious behaviors and diurnal cortisol rhythm during childhood

Although a robust literature has linked stable, high levels of fear across childhood to increased risk for anxiety problems, less is known about alternative pathways to anxiety. We tested two putatively normative developmental pathways of early fearfulness for their distinct associations with behavioral (anxiety-related behaviors and symptoms) and biological (diurnal cortisol) markers of anxiety risk in middle childhood in a community-based sample (n = 107). Steeper increases in fear from 6 to 36 months predicted more parent-reported anxiety symptoms at age 8 years. In addition, children who exhibited steep increases in fear during infancy were overrepresented among children with diagnoses of separation anxiety disorder at age 8 years. Finally, we showed that steeper increases in fearfulness in infancy predicted flatter slopes of diurnal cortisol at age 8 years for girls. Thus, differences in stranger fear across infancy may indicate varying degrees of risk for anxious behaviors in later childhood.

Effects of interpersonal violence-related post-traumatic stress disorder (PTSD) on mother and child diurnal cortisol rhythm and cortisol reactivity to a laboratory stressor involving separation

Women who have experienced interpersonal violence (IPV) are at a higher risk to develop posttraumatic stress disorder (PTSD), with dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis and impaired social behavior. Previously, we had reported impaired maternal sensitivity and increased difficulty in identifying emotions (i.e. alexithymia) among IPV-PTSD mothers. One of the aims of the present study was to examine maternal IPV-PTSD salivary cortisol levels diurnally and reactive to their child's distress in relation to maternal alexithymia. Given that mother-child interaction during infancy and early childhood has important long-term consequences on the stress response system, toddlers' cortisol levels were assessed during the day and in response to a laboratory stressor. Mothers collected their own and their 12-48month-old toddlers' salivary samples at home three times: 30min after waking up, between 2-3pm and at bedtime. Moreover, mother-child dyads participated in a 120-min laboratory session, consisting of 3 phases: baseline, stress situation (involving mother-child separation and exposure to novelty) and a 60-min regulation phase. Compared to non-PTSD controls, IPV-PTSD mothers - but not their toddlers, had lower morning cortisol and higher bedtime cortisol levels. As expected, IPV-PTSD mothers and their children showed blunted cortisol reactivity to the laboratory stressor. Maternal cortisol levels were negatively correlated to difficulty in identifying emotions. Our data highlights PTSD-IPV-related alterations in the HPA system and its relevance to maternal behavior. Toddlers of IPV-PTSD mothers also showed an altered pattern of cortisol reactivity to stress that potentially may predispose them to later psychological disorders.

Cortisol and DHEA in development and psychopathology

Dehydroepiandrosterone (DHEA) and cortisol are the most abundant hormones of the human fetal and adult adrenals released as end products of a tightly coordinated endocrine response to stress. Together, they mediate short- and long-term stress responses and enable physiological and behavioral adjustments necessary for maintaining homeostasis. Detrimental effects of chronic or repeated elevations in cortisol on behavioral and emotional health are well documented. Evidence for actions of DHEA that offset or oppose those of cortisol has stimulated interest in examining their levels as a ratio, as an alternate index of adrenocortical activity and the net effects of cortisol. Such research necessitates a thorough understanding of the co-actions of these hormones on physiological functioning and in association with developmental outcomes. This review addresses the state of the science in understanding the role of DHEA, cortisol, and their ratio in typical development and developmental psychopathology. A rationale for studying DHEA and cortisol in concert is supported by physiological data on the coordinated synthesis and release of these hormones in the adrenal and by their opposing physiological actions. We then present evidence that researching cortisol and DHEA necessitates a developmental perspective. Age-related changes in DHEA and cortisol are described from the perinatal period through adolescence, along with observed associations of these hormones with developmental psychopathology. Along the way, we identify several major knowledge gaps in the role of DHEA in modulating cortisol in typical development and developmental psychopathology with implications for future research.

Links between early baseline cortisol, attachment classification, and problem behaviors: A test of differential susceptibility versus diathesis-stress

The purpose of the current study was to predict concurrent levels of problem behaviors from young children's baseline cortisol and attachment classification, a proxy for the quality of caregiving experienced. In a sample of 58 children living at or below the federal poverty threshold, children's baseline cortisol levels, attachment classification, and problem behaviors were assessed at 17 months of age. We hypothesized that an interaction between baseline cortisol and attachment classification would predict problem behaviors above and beyond any main effects of baseline cortisol and attachment. However, based on limited prior research, we did not predict whether or not this interaction would be more consistent with diathesis-stress or differential susceptibility models. Consistent with diathesis-stress theory, the results indicated no significant differences in problem behavior levels among children with high baseline cortisol. In contrast, children with low baseline cortisol had the highest level of problem behaviors in the context of a disorganized attachment relationship. However, in the context of a secure attachment relationship, children with low baseline cortisol looked no different, with respect to problem behavior levels, then children with high cortisol levels. These findings have substantive implications for the socioemotional development of children reared in poverty.

No association between hair cortisol or cortisone and brain morphology in children

Little is known about the relationship between the long-term hypothalamic-pituitary-adrenal (HPA) axis functioning and brain structure in children. Glucocorticoid in hair has emerged as an important biomarker of HPA activity. In this study, we investigated the associations of hair cortisol and cortisone concentrations with brain morphology in young children. We included 219 children aged 6-10 years from the Generation R Study in Rotterdam, the Netherlands. We examined cortisol and cortisone concentrations by hair analysis using liquid chromatography-tandem mass spectrometry, and assessed brain morphometric measures with structural magnetic resonance imaging. The relationships of hair cortisol and cortisone concentrations with brain volumetrics, cortical thickness, cortical surface area and gyrification were analyzed separately after adjustment for several potential confounding factors. We observed a positive association between cortisol concentrations and cortical surface area in the parietal lobe, positive associations of cortisone concentrations with thalamus volume, occipital lobe volume and cortical surface area in the parietal lobe, and a negative association between cortisone concentrations and cortical surface area in the temporal lobe in the regions of interest analyses. A negative association between cortisol or cortisone concentrations and hippocampal volume was observed in children with behavioral problems. The whole brain vertex-wise analyses did however not show any association between cortisol or cortisone concentration and brain morphometric measures after correction for multiple testing. Although some associations are noted in region of interest analyses, we do not observe clear association of hair cortisol or cortisone with brain morphometric measures in typically developing young children.

Biological sensitivity to context: Cortisol awakening response moderates the effects of neighbourhood density on the development of adolescent externalizing problem behaviours

This four-year longitudinal study attempted to test person-environment interaction theory and biological sensitivity theory by assessing whether individuals' biological stress activity CARAUCg (Cortisol Awakening Response Area Under the Curve with respect to ground) moderates the effects of neighbourhood density on the development of adolescent externalizing problem behaviours. Participants were 358 Dutch adolescents with a mean age of 15 years at the first measurement. Our analyses showed that CARAUCg moderated the effects of neighbourhood density on the level of parent-reported delinquency and aggression and adolescent self-reported delinquency. More specifically, for adolescents with high CARAUCg, higher neighbourhood density significantly predicted higher levels of parent-reported and adolescent self-reported delinquency and aggression, whereas the association was reversed or non-significant for adolescents with low CARAUCg. Our findings suggest that adolescents with different levels of CARAUCg respond differentially to the density of the neighbourhood they live in, supporting for person-environment interaction perspectives and biological sensitivity theory.

Differential relations between youth internalizing/externalizing problems and cortisol responses to performance vs. interpersonal stress

Efforts to define hypothalamic-pituitary-adrenal (HPA) axis profiles conferring risk for psychopathology have yielded inconclusive results, perhaps in part due to limited assessment of the stress response. In particular, research has typically focused on HPA responses to performance tasks, while neglecting the interpersonal stressors that become salient during adolescence. In this study we investigated links between psychosocial adjustment - youth internalizing and externalizing problems, as well as competence - and HPA responses to both performance and interpersonal stressors in a normative sample of children and adolescents. Participants (n = 59) completed a set of performance (public speaking, mental arithmetic, mirror tracing) and/or interpersonal (peer rejection) tasks and gave nine saliva samples, which were assayed for cortisol. Hierarchical linear models of cortisol response trajectories in relation to child behavior checklist (CBCL) scores revealed stressor- and sex-specific associations. Whereas internalizing problems related to earlier peaking, less dynamic cortisol responses to interpersonal stress (across males and females), externalizing problems related to lower, earlier peaking and less dynamic cortisol responses to performance stress for males only, and competence-related to later peaking cortisol responses to interpersonal stress for females only. Implications for understanding contextual stress profiles underlying different forms of psychopathology are discussed.

Correspondence between hair cortisol concentrations and 30-day integrated daily salivary and weekly urinary cortisol measures

Characterization of cortisol production, regulation and function is of considerable interest and relevance given its ubiquitous role in virtually all aspects of physiology, health and disease risk. The quantification of cortisol concentration in hair has been proposed as a promising approach for the retrospective assessment of integrated, long-term cortisol production. However, human research is still needed to directly test and validate current assumptions about which aspects of cortisol production and regulation are reflected in hair cortisol concentrations (HCC). Here, we report findings from a validation study in a sample of 17 healthy adults (mean±SD age: 34±8.6 yrs). To determine the extent to which HCC captures cumulative cortisol production, we examined the correspondence of HCC, obtained from the first 1cm scalp-near hair segment, assumed to retrospectively reflect 1-month integrated cortisol secretion, with 30-day average salivary cortisol area-under-the curve (AUC) based on 3 samples collected per day (on awakening, +30min, at bedtime) and the average of 4 weekly 24-h urinary free cortisol (UFC) assessments. To further address which aspects of cortisol production and regulation are best reflected in the HCC measure, we also examined components of the salivary measures that represent: (1) production in response to the challenge of awakening (using the cortisol awakening response [CAR]), and (2) chronobiological regulation of cortisol production (using diurnal slope). Finally, we evaluated the test-retest stability of each cortisol measure. Results indicate that HCC was most strongly associated with the prior 30-day integrated cortisol production measure (average salivary cortisol AUC) (r=0.61, p=0.01). There were no significant associations between HCC and the 30-day summary measures using CAR or diurnal slope. The relationship between 1-month integrated 24-h UFC and HCC did not reach statistical significance (r=0.30, p=0.28). Lastly, of all cortisol measures, test-retest correlations of serial measures were highest for HCC (month-to-month: r=0.84, p<0.001), followed by 24-h UFC (week-to-week: r's between 0.59 and 0.68, ps<0.05) and then integrated salivary cortisol concentrations (week-to-week: r's between 0.38 and 0.61, p's between 0.13 and 0.01). These findings support the contention that HCC provides a reliable estimate of long-term integrated free cortisol production that is aligned with integrated salivary cortisol production measured over a corresponding one-month period.

Salivary latent trait cortisol (LTC): Relation to lipids, blood pressure, and body composition in middle childhood

Adversity experienced early in life has the potential to influence physical health later in life. The stress-health relation may be partially explained by stress-related effects on cardiovascular risk factors. This study explored links between individual differences in trait-like variation in the activity of the hypothalamic-pituitary-adrenal (HPA) axis with cardiovascular risk factors in children. 474 children (M age=9.22years; 54% female; 83% Caucasian) were included in this study, in which cardiovascular risk was assessed using the following indices - triglycerides (TG), HDL-cholesterol (HDL-C), glucose (Glu); resting systolic and diastolic blood pressure, body mass index (BMI), waist-to-hip ratio, and % fat. Saliva samples were measured 3 times a day (waking, 30min post-waking and bedtime) over 3days (later assayed for cortisol). A latent trait cortisol (LTC) factor explained 43% of the variance in cortisol levels within and across days. Confirmatory factor analysis identified three cardiovascular risk factors: lipids (i.e., TG and HDL-C), blood pressure (i.e., systolic and diastolic), and body composition (i.e., BMI, Waist-to-hip ratio, and % fat). Lower salivary LTC was associated with higher lipids, higher blood pressure, and higher body composition. The findings further support the internal and external validity of the LTC construct, and may also advance our understanding of the link between interindividual differences in HPA axis activity and cardiovascular risk in middle childhood.

The neurobiological basis of human aggression: A review on genetic and epigenetic mechanisms

Aggression is an evolutionary conserved behavior present in most species including humans. Inadequate aggression can lead to long-term detrimental personal and societal effects. Here, we differentiate between proactive and reactive forms of aggression and review the genetic determinants of it. Heritability estimates of aggression in general vary between studies due to differing assessment instruments for aggressive behavior (AB) as well as age and gender of study participants. In addition, especially non-shared environmental factors shape AB. Current hypotheses suggest that environmental effects such as early life stress or chronic psychosocial risk factors (e.g., maltreatment) and variation in genes related to neuroendocrine, dopaminergic as well as serotonergic systems increase the risk to develop AB. In this review, we summarize the current knowledge of the genetics of human aggression based on twin studies, genetic association studies, animal models, and epigenetic analyses with the aim to differentiate between mechanisms associated with proactive or reactive aggression. We hypothesize that from a genetic perspective, the aminergic systems are likely to regulate both reactive and proactive aggression, whereas the endocrine pathways seem to be more involved in regulation of reactive aggression through modulation of impulsivity. Epigenetic studies on aggression have associated non-genetic risk factors with modifications of the stress response and the immune system. Finally, we point to the urgent need for further genome-wide analyses and the integration of genetic and epigenetic information to understand individual differences in reactive and proactive AB. © 2015 Wiley Periodicals, Inc.

Dysregulation of the cortisol diurnal rhythm following prenatal alcohol exposure and early life adversity

The hypothalamic-pituitary-adrenal (HPA) axis is impacted by a multitude of pre- and postnatal factors. Developmental programming of HPA axis function by prenatal alcohol exposure (PAE) has been demonstrated in animal models and in human infants, but remains understudied in older children and adolescents. Moreover, early life adversity (ELA), which occurs at higher rates in children with PAE than in non-exposed children, may also play a role in programming the stress response system. In a cohort of children and adolescents with PAE and ELA (PAE + ELA), we evaluated HPA function through assessment of diurnal cortisol activity compared to that in typically developing controls, as well as the associations among specific ELAs, adverse outcomes, protective factors, and diurnal cortisol. Morning and evening saliva samples were taken under basal conditions from 42 children and adolescents (5-18 years) with PAE + ELA and 43 typically developing controls. High rates of ELA were shown among children with PAE, and significantly higher evening cortisol levels and a flatter diurnal slope were observed in children with PAE + ELA, compared to controls. Medication use in the PAE + ELA group was associated with lower morning cortisol levels, which were comparable to controls. Complex associations were found among diurnal cortisol patterns in the PAE + ELA group and a number of ELAs and later adverse outcomes, whereas protective factors were associated with more typical diurnal rhythms. These results complement findings from research on human infants and animal models showing dysregulated HPA function following PAE, lending weight to the suggestion that PAE and ELA may interact to sensitize the developing HPA axis. The presence of protective factors may buffer altered cortisol regulation, underscoring the importance of early assessment and interventions for children with FASD, and in particular, for the many children with FASD who also have ELA.

Latent trait testosterone among 18-24 year olds: Methodological considerations and risk associations

The study investigated the relationship between latent trait testosterone (LTT) and risk-taking among 126 youth (M age=21.34years; 56% female; 52% African American). Latent state-trait (LST) modeling isolates observed variance of samples via their correlations into (1) a latent trait testosterone (LTT) factor capturing individual differences, and (2) a component of state testosterone factor (LST) capturing state-specific situational or environmental influences and random error variances. Participants provided four laboratory (20min apart) and four home (waking, 20-min post-waking, noon, evening) salivary samples (later assayed for testosterone). Participants reported risk-taking tendencies and behaviors via an Audio Computer Assisted Self-Interview. Behavioral risk was measured using the Balloon Analog Risk Task. Results revealed: (1) LTT model invariance (operated similarly) for females and males; (2) LTT accounted for 18-89% (home samples) and 61-95% (lab samples) of the variance in testosterone levels, and (3) LTT was associated with risk-seeking behaviors and the strength of this association was similar across males and females. LST Modeling has potential to advance our understanding of testosterone-behavior associations to new limits by estimating stable trait-like components of the variance in testosterone levels.