Early institutionalization: neurobiological consequences and genetic modifiers

Associations of Duration of Preadoption Out-of-home Care, Genetic Risk for Schizophrenia Spectrum Disorders and Adoptive Family Functioning with Later Psychiatric Disorders of Adoptees

The objective was to examine the impacts of duration of preadoption out-of-home care and adoptive family functioning on later psychiatric morbidity of adoptees with high (HR) and low (LR) genetic risk for schizophrenia spectrum disorders. The study uses nationwide data from the Finnish Adoptive Family Study of Schizophrenia. The study population in this substudy consisted of 43 h adoptees and 128 LR adoptees. Of these adoptees, 90 had spent 0-6 months and 81 over 6 months in preadoption out-of-home care. The family functioning of adoptive families was assessed based on Global Family Ratings and psychiatric disorders on DSM-III-R criteria. The results showed that among the adoptees with over 6 months in preadoption out-of-home care, the likelihood for psychiatric disorders was significantly increased in HR adoptees compared to LR adoptees. In adoptees with 6 months or less in preadoption out-of-home care, an increased likelihood for psychiatric disorders was found among those living in adoptive families with dysfunctional processes. These findings indicate that especially for HR children, a well-functioning early caregiving environment is crucial in terms of subsequent mental wellbeing. The results emphasize that when adoption is necessary, early placement and well-functioning adoptive family environment are beneficial to children.

Emotional-behavioral problems, attachment and verbal skills in late-adopted adolescents: The role of pre-adoption adversities and adoption variables

BACKGROUND

There are few studies on late-adopted adolescents' outcomes -e.g., emotional-behavioral problems, attachment and cognitive status- and their possible predictive factors, none from Italy.

OBJECTIVE

This paper aimed to investigate emotional-behavioral problems, attachment representations, and verbal skills in late-adopted adolescents in Italy and to explore the predictive role of pre-adoption adversities and adoption variables for worse adoptees' outcomes.

PARTICIPANTS AND SETTING

The study included N = 79 late-adopted (mean age at adoption = 6 years) adolescents, between 11 and 18 years, placed via both intercountry and domestic adoption.

METHODS

Parents provided information about pre-adoption and adoption history and filled the Children's Behavior Checklist 6-18 for measuring participants' emotional-behavioral problems. Attachment representations were assessed through the Friend and Family Interview administered directly to adolescents, like the verbal comprehension index of the Wechsler Intelligence Scale for Children (4th edition) for measuring participants' verbal IQ.

RESULTS

Maltreatment and its interaction with multiple placements were the main predictors of other problems-i.e., social, thought, and identity difficulties (respectively, p = .007 and p = .029)-while intercountry adoption was the unique predictor of both externalizing and total problems (respectively, p = .047 and p = .015). However, domestic adoption was the most important predictor both for higher insecurity and disorganized attachment representations and lower verbal skills (all p < .044); even stronger if domestic adoption interacted with pre-adoptive institutionalization.

CONCLUSIONS

Pre-adoption adversities as well as domestic vs. intercountry adoption, but not the age at placement, contributed to adolescent adoptees' developmental outcomes.

Measuring early life adversity: A dimensional approach

Exposure to adversity in childhood is associated with elevations in numerous physical and mental health outcomes across the life course. The biological embedding of early experience during periods of developmental plasticity is one pathway that contributes to these associations. Dimensional models specify mechanistic pathways linking different dimensions of adversity to health and well-being outcomes later in life. While findings from existing studies testing these dimensions have provided promising preliminary support for these models, less agreement exists about how to measure the experiences that comprise each dimension. Here, we review existing approaches to measuring two dimensions of adversity: threat and deprivation. We recommend specific measures for measuring these constructs and, when possible, document when the same measure can be used by different reporters and across the lifespan to maximize the utility with which these recommendations can be applied. Through this approach, we hope to stimulate progress in understanding how particular dimensions of early environmental experience contribute to lifelong health.

Differential Associations of Deprivation and Threat With Cognitive Control and Fear Conditioning in Early Childhood

Early-life adversity (ELA) is strongly associated with risk for psychopathology. Within adversity, deprivation, and threat may lead to psychopathology through different intermediary pathways. Specifically, deprivation, defined as the absence of expected cognitive and social inputs, is associated with lower performance on complex cognitive tasks whereas threatening experiences, defined as the presence of experiences that reflect harm to the child, are associated with atypical fear learning and emotional processes. However, distinct associations of deprivation and threat on behavioral outcomes have not been examined in early childhood. The present study examines how deprivation and threat are associated with cognitive and emotional outcomes in early childhood. Children 4–7 years old completed behavioral tasks assessing cognitive control (N = 58) and fear conditioning (N = 45); deprivation and threat were assessed using child interview and parent questionnaires. Regression analyses were performed including deprivation and threat scores and controls for age, gender, and IQ. Because this is the first time these variables have been examined in early childhood, interactions with age were also examined. Deprivation, but not threat was associated with worse performance on the cognitive control task. Threat, but not deprivation interacted with age to predict fear learning. Young children who experienced high levels of threat showed evidence of fear learning measured by differential skin conductance response even at the earliest age measured. In contrast, for children not exposed to threat, fear learning emerged only in older ages. Children who experienced higher levels of threat also showed blunted reactivity measured by amplitude of skin conductance response to the reinforced stimuli regardless of age. Results suggest differential influences of deprivation and threat on cognitive and emotional outcomes even in early childhood. Future work should examine the neural mechanisms underlying these behavioral changes and link changes with increased risk for negative outcomes associated with adversity exposure, such as psychopathology.

Adolescents with Persistent History of Maltreatment Fail in Antisaccadic Task

The antisaccadic task is sensitive to what is called frontal dysfunction, i.e. dysfunction of the frontal lobes of the cerebral cortex which are the basis for a wide range of symptoms. The present study examined saccadic eye movements in adolescents with persistent history of maltreatment. Participants included 17 female subjects with maltreatment history. The control group consisted of 54 typically developing female subjects. All participants were administered Child Behavior Checklist (CBCL) and saccadic eye movement tests. CBCL showed significant differences between the maltreated and control groups. The prosaccadic test revealed insignificant results between both groups. The antisaccadic test revealed a highly significant difference (longer latencies, more prosaccadic mistakes in the group of maltreated subjects). Antisaccadic eye movements may be regarded as a possible indicator of persistent maltreatment and following emotional and behavioral problems and may therefore enhance diagnostic methods.

ADHD Symptoms in Post-Institutionalized Children Are Partially Mediated by Altered Frontal EEG Asymmetry

Individual differences in the propensity for left versus right frontal electroencephalogram (EEG) asymmetry may underlie differences in approach/withdrawal tendencies and mental health deficits. Growing evidence suggests that early life adversity may shape brain development and contribute to the emergence of mental health problems. The present study examined frontal EEG asymmetry (FEA) following the transition to family care in children adopted internationally from institutional care settings between 15 and 36 months of age (N = 82; 46 female, 36 male). Two comparison groups were included: an international adoption control consisting of children adopted from foster care with little to no institutional deprivation (N = 45; 17 female, 28 male) and a post-adoption condition control consisting of children reared in birth families of the same education and income as the adoptive families (N = 48; 23 female, 25 male). Consistent with evidence of greater approach and impulsivity-related behavior problems in post-institutionalized (PI) children, PI status was associated with greater left FEA than found in the other two groups. In addition, left FEA served as a mediator between institutionalization and age 5 ADHD symptoms for girls. Age at adoption and other preadoption factors were examined with results suggesting that earlier adoption into a supportive family resulted in a more typical pattern of brain functioning. Findings support the idea that the capacity of brain activity to evidence typical functioning following perturbation may differ in relation to the timing of intervention and suggest that the earlier the intervention of adoption, the better.

Can adoption at an early age protect children at risk from depression in adulthood? A Swedish national cohort study

OBJECTIVE

Our aim was to investigate whether the risk of depression in adulthood in children raised by substitute parents from an early age differ by care arrangements.

METHODS

Register study in Swedish national cohorts born 1972-1981, with three study groups of children raised in adoptive or foster homes with care starting before the age of 2 years and a comparison majority population group. Cox regression estimated HRs of prescribed antidepressive medication and specialised psychiatric care with a diagnosis of depression in adulthood during 2006-2012.

RESULTS

Compared with the general population, long-term foster care carried the highest age-adjusted and sex-adjusted HR for both antidepressive medication, 2.07 (95% CI 1.87 to 2.28), and psychiatric care for depression, 2.85 (95% CI 2.42 to 3.35), in adulthood. Adults raised by adoptive parents were far more similar to the general population with HR of 1.19 (95% CI 1.00 to 1.43) for domestic and 1.13 (95% CI 1.08 to 1.18) for international adoption for antidepressive medication. Adjusting the analysis for school marks and income attenuated these risks more in the long-term foster care group.

CONCLUSION

The study demonstrates the benefits of early adoption when substitute parents are provided for young children, and underlines the importance of improved educational support for children in foster care.

Serotonin transporter polymorphism moderates the effects of caregiver intrusiveness on ADHD symptoms among institutionalized preschoolers

Research consistently chronicles a variety of mental health difficulties that plague institutionally reared children, including attention-deficit/hyperactivity disorder (ADHD), even if not all institutionalized children evince such problems. In seeking to extend work in this area, this research on gene × environment (GXE) interplay investigated whether the effect of the quality of institutional care-most notably, caregiver intrusiveness-on ADHD symptoms is moderated by the serotonin transporter (5-HTTLPR) polymorphism. One hundred and twenty-seven institutionalized preschoolers were evaluated using the Child Behavior Checklist. Caregiver-rated attention problems and hyperactivity were unrelated to both 5-HTTLPR polymorphism and caregiver intrusiveness. A significant GXE effect, independent of age at placement or duration of institutionalization, emerged, however, consistent with the differential-susceptibility hypothesis: s/s homozygotes manifest the most and least ADHD symptoms when they experienced, respectively, more and less intrusive caregiving. These results provide new insight into the reasons why some institutionalized children, but not others, exhibit ADHD symptoms.

Consequences of early adverse rearing experience(EARE) on development: insights from non-human primate studies

Early rearing experiences are important in one's whole life, whereas early adverse rearing experience(EARE) is usually related to various physical and mental disorders in later life. Although there were many studies on human and animals, regarding the effect of EARE on brain development, neuroendocrine systems, as well as the consequential mental disorders and behavioral abnormalities, the underlying mechanisms remain unclear. Due to the close genetic relationship and similarity in social organizations with humans, non-human primate(NHP) studies were performed for over 60 years. Various EARE models were developed to disrupt the early normal interactions between infants and mothers or peers. Those studies provided important insights of EARE induced effects on the physiological and behavioral systems of NHPs across life span, such as social behaviors(including disturbance behavior, social deficiency, sexual behavior, etc), learning and memory ability, brain structural and functional developments(including influences on neurons and glia cells, neuroendocrine systems, e.g., hypothalamic-pituitary-adrenal(HPA) axis, etc). In this review, the effects of EARE and the underlying epigenetic mechanisms were comprehensively summarized and the possibility of rehabilitation was discussed.

Adopted youth and sleep difficulties

Sleep is a critical component of healthy development for youth, with cascading effects on youth’s biological growth, psychological well-being, and overall functioning. Increased sleep difficulties are one of many disruptions that adopted youth may face throughout the adoption process. Sleep difficulties have been frequently cited as a major concern by adoptive parents and hypothesized in the literature as a problem that may affect multiple areas of development and functioning in adopted youth. However, there is limited research exploring this relationship. Using a biopsychosocial framework, this paper reviews the extant literature to explore the development, maintenance, and impact of sleep difficulties in adopted youth. Finally, implications for future research and clinical interventions are outlined.

Of rodents and humans: A comparative review of the neurobehavioral effects of early life SSRI exposure in preclinical and clinical research

Selective serotonin reuptake inhibitors (SSRIs) have been a mainstay pharmacological treatment for women experiencing depression during pregnancy and postpartum for the past 25 years. SSRIs act via blockade of the presynaptic serotonin transporter and result in a transient increase in synaptic serotonin. Long-lasting changes in cellular function such as serotonergic transmission, neurogenesis, and epigenetics, are thought to underlie the therapeutic benefits of SSRIs. In recent years, though, growing evidence in clinical and preclinical settings indicate that offspring exposed to SSRIs in utero or as neonates exhibit long-lasting behavioral adaptions. Clinically, children exposed to SSRIs in early life exhibit increased internalizing behavior reduced social behavior, and increased risk for depression in adolescence. Similarly, rodents exposed to SSRIs perinatally exhibit increased traits of anxiety- or depression-like behavior. Furthermore, certain individuals appear to be more susceptible to early life SSRI exposure than others, suggesting that perinatal SSRI exposure may pose greater risks for negative outcome within certain populations. Although SSRIs trigger a number of intracellular processes that likely contribute to their therapeutic effects, early life antidepressant exposure during critical neurodevelopmental periods may elicit lasting negative effects in offspring. In this review, we cover the basic development and structure of the serotonin system, how the system is affected by early life SSRI exposure, and the behavioral outcomes of perinatal SSRI exposure in both clinical and preclinical settings. We review recent evidence indicating that perinatal SSRI exposure perturbs the developing limbic system, including altered serotonergic transmission, neurogenesis, and epigenetic processes in the hippocampus, which may contribute to behavioral domains (e.g., sociability, cognition, anxiety, and behavioral despair) that are affected by perinatal SSRI treatment. Identifying the molecular mechanisms that underlie the deleterious behavioral effects of perinatal SSRI exposure may highlight biological mechanisms in the etiology of mood disorders. Moreover, because recent studies suggest that certain individuals may be more susceptible to the negative consequences of early life SSRI exposure than others, understanding mechanisms that drive such susceptibility could lead to individualized treatment strategies for depressed women who are or plan to become pregnant.

Serotonin transporter linked polymorphic region (5-HTTLPR) genotype moderates the longitudinal impact of early caregiving on externalizing behavior

We examined caregiver report of externalizing behavior from 12 to 54 months of age in 102 children randomized to care as usual in institutions or to newly created high-quality foster care. At baseline no differences by group or genotype in externalizing were found. However, changes in externalizing from baseline to 42 months of age were moderated by the serotonin transporter linked polymorphic region genotype and intervention group, where the slope for short-short (S/S) individuals differed as a function of intervention group. The slope for individuals carrying the long allele did not significantly differ between groups. At 54 months of age, S/S children in the foster care group had the lowest levels of externalizing behavior, while children with the S/S genotype in the care as usual group demonstrated the highest rates of externalizing behavior. No intervention group differences were found in externalizing behavior among children who carried the long allele. These findings, within a randomized controlled trial of foster care compared to continued care as usual, indicate that the serotonin transporter linked polymorphic region genotype moderates the relation between early caregiving environments to predict externalizing behavior in children exposed to early institutional care in a manner most consistent with differential susceptibility.

Neighborhood social capital and infant physical abuse: a population-based study in Japan

Purpose

We sought to investigate the relationship between neighborhood social capital and infant physical abuse using a population-based sample of women with 4-month-old infants in Japan.

Methods

A questionnaire was administered to women who participated in a 4-month health checkup program (n = 1277; valid response rate, 80 %). We inquired about their perceptions of the level of trust in their neighborhood (an indicator of “social capital”) as well as the availability of support from their personal social networks. Infant physical abuse during the past month was assessed by self-reports of spanking, shaking or smothering.

Results

The prevalence of infant physical abuse at 4 months of age was 9.0 % (95 % confidence interval [CI], 7.6–10.7 %). Women living in trusting neighborhoods were less likely to report infant physical abuse compared to those living in areas with low neighborhood trust (odds ratio [OR] 0.25, 95 % CI 0.06–0.97). In addition, women with supportive social networks were less likely to report infant physical abuse (OR 0.59, 95 % CI 0.36–0.99).

Conclusions

In addition to one’s personal social network, social trust in the neighborhood was independently associated with lowered risk of infant physical abuse. To prevent infant abuse, interventions should consider strengthening community social bonds in addition to strengthening the social network of isolated mothers.

Deconstructing the function of maternal stimulation in offspring development: Insights from the artificial rearing model in rats

This article is part of a Special Issue on "Parental Care". Maternal behavior has an important function in stimulating adequate growth and development of the young. Several approaches have been used in primates and rodents to deconstruct and examine the influence of specific components of maternal stimulation on offspring development. These approaches include observational studies of typical mother-infant interactions and studies of the effects of intermittent or complete deprivation of maternal contact. In this review, we focus on one unique approach using rats that enables the complete control of maternal variables by means of rearing rat pups artificially without contact with the mother or litter, while maintaining stable nutrition, temperature and exposure to stressful stimuli. This artificial rearing model permits the removal and controlled replacement of relevant maternal and litter stimuli and has contributed valuable insights regarding the influence of these stimuli on various developmental outcomes. It also enables the analysis of factors implicated in social isolation itself and their long-term influence. We provide an overview of the effects of artificial rearing on behavior, physiology, and neurobiology, including the influence of replacing maternal tactile stimulation and littermate contact on these outcomes. We then discuss the relevance of these effects in terms of the maternal role in regulating different aspects of offspring development and implications for human research. We emphasize that artificial rearing of rats does not lead to a global insult of nervous system development, making this paradigm useful in investigating specific developmental effects associated with maternal stimulation.

When mothering goes awry: Challenges and opportunities for utilizing evidence across rodent, nonhuman primate and human studies to better define the biological consequences of negative early caregiving

This article is part of a Special Issue "Parental Care".Across mammalian species, mothers shape socio-emotional development and serve as essential external regulators of infant physiology, brain development, behavior patterns, and emotional regulation. Caregiving quality, consistency and predictability shape the infant's underlying neurobiological processes. Although the requirements for "optimal" caregiving differ across species, the negative long-term consequences of the absence of needed caregiving (e.g. neglect) or the presence of harmful/aversive caregiving (e.g. physical abuse), are translatable across species. Recognizing the significant potential of cross species comparisons in terms of defining underlying mechanisms, effective translation requires consideration of the evolutionary, ecological, and fundamental biological and developmental differences between and among species. This review provides both an overview of several success stories of cross-species translations in relation to negative caregiving and a template for future studies seeking to most effectively define the underlying biological processes and advance research dedicated to mitigating the lasting negative health consequences of child maltreatment.

Language development of internationally adopted children: Adverse early experiences outweigh the age of acquisition effect

We compared English language and cognitive skills between internationally adopted children (IA; mean age at adoption=2.24, SD=1.8) and their non-adopted peers from the US reared in biological families (BF) at two time points. We also examined the relationships between outcome measures and age at initial institutionalization, length of institutionalization, and age at adoption. On measures of general language, early literacy, and non-verbal IQ, the IA group performed significantly below their age-peers reared in biological families at both time points, but the group differences disappeared on receptive vocabulary and kindergarten concept knowledge at the second time point. Furthermore, the majority of children reached normative age expectations between 1 and 2 years post-adoption on all standardized measures. Although the age at adoption, age of institutionalization, length of institutionalization, and time in the adoptive family all demonstrated significant correlations with one or more outcome measures, the negative relationship between length of institutionalization and child outcomes remained most robust after controlling for the other variables. Results point to much flexibility and resilience in children's capacity for language acquisition as well as the potential primacy of length of institutionalization in explaining individual variation in IA children's outcomes.

LEARNING OUTCOMES

(1) Readers will be able to understand the importance of pre-adoption environment on language and early literacy development in internationally adopted children. (2) Readers will be able to compare the strength of the association between the length of institutionalization and language outcomes with the strength of the association between the latter and the age at adoption. (3) Readers will be able to understand that internationally adopted children are able to reach age expectations on expressive and receptive language measures despite adverse early experiences and a replacement of their first language with an adoptive language.

Desempenho de vocabulário em crianças pré-escolares institucionalizadas

OBJETIVO: verificar o desempenho de vocabulário de crianças institucionalizadas e comparar com o desempenho de crianças pertencentes à rede pública e particular de ensino. MÉTODOS: participaram deste estudo 16 crianças em situação de acolhimento institucional em abrigo, de ambos os gêneros, com idades entre 4 anos a 5 anos e 11 meses (grupo experimental). Para compor o grupo controle, participaram 32 crianças provenientes de escolas pública (n=16) e privada (n=16) pareadas por idade, totalizando 48 participantes. Para a verificação do desempenho de vocabulário foi utilizado o Teste de Vocabulário - ABFW que verifica a competência lexical da criança e os recursos de significação utilizados para nomear a palavra alvo. Foi realizada a análise estatística dos dados a fim de analisar diferenças entre os grupos pesquisados (Teste de Kruskal-Wallis). RESULTADOS: foi possível observar que as crianças institucionalizadas demonstraram desempenho inferior na prova de vocabulário em relação aos grupos controle, que não apresentaram grandes diferenças entre si. Cabe mencionar que todas as crianças demonstraram maior dificuldade nos campos conceituais "profissões" e "locais". CONCLUSÃO: crianças em situação de acolhimento institucional em abrigo possuem desempenho vocabulário abaixo do esperado para a idade e inferior ao desempenho de pré-escolares de escolas pública e privada que residem com suas famílias.

A neurogenetics approach to defining differential susceptibility to institutional care

An individual's neurodevelopmental and cognitive sequelae to negative early experiences may, in part, be explained by genetic susceptibility. We examined whether extreme differences in the early caregiving environment, defined as exposure to severe psychosocial deprivation associated with institutional care compared to normative rearing, interacted with a biologically informed genoset comprising BDNF (rs6265), COMT (rs4680), and SIRT1 (rs3758391) to predict distinct outcomes of neurodevelopment at age 8 (N = 193, 97 males and 96 females). Ethnicity was categorized as Romanian (71%), Roma (21%), unknown (7%), or other (1%). We identified a significant interaction between early caregiving environment (i.e., institutionalized versus never institutionalized children) and the a priori defined genoset for full-scale IQ, two spatial working memory tasks, and prefrontal cortex gray matter volume. Model validation was performed using a bootstrap resampling procedure. Although we hypothesized that the effect of this genoset would operate in a manner consistent with differential susceptibility, our results demonstrate a complex interaction where vantage susceptibility, diathesis stress, and differential susceptibility are implicated.

Attention and language as mediators of academic outcomes following early psychosocial deprivation

Children adopted from institutions at older ages are at increased risk of persistent attention problems, lower cognition, and academic difficulties. This study examined cognitive and behavior problems as mediators of the association between early psychosocial deprivation and academic functioning. Participants were 8–17-year-old children adopted from psychosocially-depriving Russian institutions after 14 months of age ( n = 34) and before 9 months of age ( n = 39). Children completed a cognitive assessment, while their parents completed questionnaires on child behavior problems and use of learning support services in school. Children adopted after 14 months were found to have significantly lower vocabulary, higher levels of attention problems, and higher rates of using learning support services relative to children adopted before 9 months after controlling for age at assessment. The two groups did not differ significantly in nonverbal reasoning, anxiety, or oppositional behavior. Attention and vocabulary significantly mediated the association of early psychosocial deprivation with the use of learning support services. These findings suggest that interventions targeting attention regulatory and language skills may be beneficial in terms of improving school performance in this population.

Inhibitory control and working memory in post-institutionalized children

Inhibitory control and working memory were examined in post-institutionalized (PI) children adopted into United States families from Russian institutions. The PI sample originated from institutions that were less severely depriving than those represented in previous studies and approximated the level of psychosocial deprivation, which is characterized by adequate physical resources but a lack of consistent and responsive caregiving. PI children (N = 75; 29 male) ranged in age from 8-17 years (M = 12.97; SD = 3.03) and were grouped according to whether they were adopted after 14 months or before 9 months. A non-adopted comparison group (N = 133; 65 male) ranged in age from 8-17 years (M = 12.26; SD = 2.75). PI children adopted after 14 months of age displayed poorer performance on the stop-signal and spatial span tasks relative to PI children adopted before 9 months of age after controlling for age at assessment. The two PI groups did not differ in their performance on a spatial self-ordered search task. Older-adopted PI children also showed poorer spatial span task performance compared to non-adopted children, but younger-adopted PI children did not. Task performance was significantly associated with parent-rated hyperactive-impulsive behavior in everyday contexts. These findings suggest that exposure to prolonged early institutional deprivation may be linked with inhibitory control and working memory difficulties years after adoption.

Parent-reported executive functioning in postinstitutionalized children: a follow-up study

This study compared parent-rated executive functioning (EF) in 6- to 18-year-old children adopted from psychosocially depriving institutions to that in children adopted from severely or "globally" depriving institutions. Individual continuity in EF over 2 years was examined in children adopted from psychosocially depriving institutions. There were 471 children adopted from psychosocially depriving Russian institutions that provided adequate physical resources but failed to provide a consistent set of responsive caregivers. There were 111 children adopted in the early 1990s from globally depriving Romanian institutions that were characterized by physical deprivation as well as profound psychosocial neglect. Adoptive parents completed a background questionnaire and the Behavior Rating Inventory of Executive Function (BRIEF). Children adopted from globally depriving institutions had significantly higher levels of EF difficulties than children adopted from psychosocially depriving institutions. For both groups, adoption after 18 months of age was associated with higher levels of EF difficulties. Children adopted from globally depriving institutions had higher levels of EF difficulties than the BRIEF standardization sample at younger ages at adoption. There was moderate to strong continuity in EF difficulties over 2 years in children adopted from psychosocially depriving institutions. These findings suggest that more severe early deprivation may lead to a higher risk of later EF difficulties, which may persist over time.

Telomere length and early severe social deprivation: linking early adversity and cellular aging

Accelerated telomere length attrition has been associated with psychological stress and early adversity in adults; however, no studies have examined whether telomere length in childhood is associated with early experiences. The Bucharest Early Intervention Project is a unique randomized controlled trial of foster care placement compared with continued care in institutions. As a result of the study design, participants were exposed to a quantified range of time in institutional care, and represented an ideal population in which to examine the association between a specific early adversity, institutional care and telomere length. We examined the association between average relative telomere length, telomere repeat copy number to single gene copy number (T/S) ratio and exposure to institutional care quantified as the percent of time at baseline (mean age 22 months) and at 54 months of age that each child lived in the institution. A significant negative correlation between T/S ratio and percentage of time was observed. Children with greater exposure to institutional care had significantly shorter relative telomere length in middle childhood. Gender modified this main effect. The percentage of time in institutional care at baseline significantly predicted telomere length in females, whereas the percentage of institutional care at 54 months was strongly predictive of telomere length in males. This is the first study to demonstrate an association between telomere length and institutionalization, the first study to find an association between adversity and telomere length in children, and contributes to the growing literature linking telomere length and early adversity.

Update on environmental risk factors for attention-deficit/hyperactivity disorder

Attention-deficit/hyperactivity disorder (ADHD) is a prevalent neurobehavioral disorder affecting 5% to 10% of children. Although considered to be a highly familial disorder, ADHD heritability estimates of 60% to 80% highlight the considerable role that environmental factors may still play in disorder susceptibility. Proposed ADHD environmental risk factors include prenatal substance exposures, heavy metal and chemical exposures, nutritional factors, and lifestyle/psychosocial factors. This paper reviews the literature published in 2010 investigating the association between environmental risk factors and ADHD or related symptomatology. Sources of risk factor exposure and the proposed mechanism by which each exposure is linked to ADHD-related neurobehavioral changes are also reported. Methodologic limitations of the current literature are discussed, and guidelines for future study are proposed. An improved understanding of the role that environmental factors play in ADHD etiology is critical to future ADHD prevention efforts.