Internationally-adopted adolescents who are adopted as young children conditions of poverty and deprivation have poorer physical and mental health outcomes than adolescents conceived, born and raised in the US by families similar to those who adopt internationally. Using a sample of Russian and Eastern European adoptees to control for Caucasian race and US born, non-adopted offspring of well-educated and well-resourced parents to control for post-adoption conditions, we hypothesized that the important differences in environments, conception to adoption, might be reflected in epigenetic patterns between groups, specifically in DNA methylation. Thus, we conducted an epigenome-wide association study (EWAS) to compare DNA methylation profiles at approximately 416,000 individual CpG loci from peripheral blood mononuclear cells of 50 adopted youth and 33 non-adopted youth. Adopted youth averaged 22 months at adoption and both groups averaged 15 years at testing, thus roughly 80% of their lives were lived in similar circumstances. Although concurrent physical health did not differ, cell type composition predicted using the DNA methylation data revealed a striking difference in the white blood cell type composition of the adopted and non-adopted youth. After correcting for cell type and removing invariant probes, 30 CpG sites in 19 genes were more methylated in the adopted group. We also used an exploratory functional analysis that revealed that 223 Gene Ontology (GO) terms, clustered in neural and developmental categories, were significantly enriched between groups.
Developmental psychology is rapidly becoming a neuropsychobiological field concerned with understanding how the genes we are born with, the experiences we have that modify gene expression, and the physiological responses in our brains and bodies all come together to write the story of our lives. Nowhere is the importance of a multilevel, multidisciplinary, genes‐to‐society perspective more apparent than in the study of stress and its role in development. This chapter focuses on a key stress‐mediating system, the hypothalamic‐pituitary‐adrenocortical ( HPA ) axis, its development and regulatory processes, its effects on brain systems involved in emotion and cognition, and its interactions with other stress‐mediating systems. The normative development of the HPA axis is described, along with the role of temperament as a moderator of stress responding and stress effects. The majority of the chapter summarizes evidence that the HPA axis plays a role in the biological embedding of experience during development, including questions about developmental plasticity and developmental programming in relation to poverty, prenatal stress, parental loss, risky family environments, and maltreatment. The role of the HPA axis in developmental psychopathology is also discussed. Future directions and fruitful areas of research are considered with each topic.
Background Early neglect is associated with increased risk of internalizing disorders in humans and with increased fear behavior in animals. When children are adopted out of orphanages in which they experienced institutional neglect, anxiety and depressive disorders often are not seen until adolescence. What has not been examined is whether even young children adopted from institutional care exhibit heightened fear or behavioral inhibition. Method Children adopted between 15 and 35 months from institutional care were examined twice during their first year post-adoption and compared to children of the same age reared in their birth families. A modified version of the Laboratory Temperament Assessment Battery for Preschoolers was used with the children being exposed to two mechanical toys designed to be highly arousing and fear-eliciting. Because children in institutions tend to exhibit low levels of positive affect, the children were also examined during exposure to two positive stimuli. Sessions were videotaped and coded by observers blind to the study purpose. Results Post-institutionalized children froze more in fear vignettes and were less positive in both fear and positive vignettes than non-adopted children. Group differences did not diminish significantly from the first session to the next, 6 months later. Conclusions Children exposed to early institutional neglect exhibit emotional biases that are consistent with their previously demonstrated risk for the development of internalizing disorders.
The relations between early deprivation and the development of the neuroendocrine and central components of the mammalian stress response have been examined frequently. However, little is known about the impact of early deprivation on the developmental trajectories of autonomic function. Children adopted between 15–36 months from institutional care were examined during their first 16 months post-adoption (N=60). Comparison groups included same-aged peers reared in their birth families (N=50) and children adopted internationally from overseas foster care (N=46). The present study examined trajectories of baseline autonomic nervous system function longitudinally following entry into adopted families. Post-institutionalized children had higher sympathetic tone, measured by pre-ejection period (PEP). Individual differences in PEP soon after adoption served as a mediator between early deprivation and parent-reported behavioral problems two years post-adoption. There were no group differences in parasympathetic function, indexed by respiratory sinus arrhythmia. All three groups showed similar trajectories of ANS function across the 16 month period.
Although many children adopted internationally show remarkable recovery once placed in families, as a group they continue to exhibit persisting developmental deficits and delays in self-regulation. The current study uses a stratified, randomized, controlled trial to evaluate the effects of mindfulness-based and executive function trainings (EFTs) on internationally adopted (IA) children's self-regulation, including effortful/inhibitory control, attention, delay of gratification, and emotion-regulation. IA children ages 6–10 years were randomized into mindfulness training (MT), EFT, or no intervention (NI) groups. The MT and EFT groups attended 12 one-hour group sessions. Ninety-six children (MT, n = 33; EFT, n = 32; NI, n = 31) completed the study and were tested on computerized and non-computerized measures of self-regulation. Compared with the NI group, the MT group improved delay of gratification, and the EFT group improved inhibitory control and selective attention. There was no effect of either intervention on emotion regulation. MTs and EFTs show promise for improving self-regulation in IA children.
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