Significance Disruptions in stress response system functioning are thought to be a central mechanism by which exposure to adverse early-life environments influences human development. Although rodent ...models support this possibility, results from human studies have been decidedly mixed. Using data from an experimental study examining whether random assignment to a caregiving environment alters development of the autonomic nervous system and hypothalamic–pituitary–adrenal axis in humans, we provide causal evidence for persistent effects of the early caregiving environment on stress response system functioning in humans with effects that differ markedly from those observed in rodent models. We also provide evidence of a sensitive period in human development during which the environment is particularly likely to alter stress response system development.
Disruptions in stress response system functioning are thought to be a central mechanism by which exposure to adverse early-life environments influences human development. Although early-life adversity results in hyperreactivity of the sympathetic nervous system (SNS) and hypothalamic–pituitary–adrenal (HPA) axis in rodents, evidence from human studies is inconsistent. We present results from the Bucharest Early Intervention Project examining whether randomized placement into a family caregiving environment alters development of the autonomic nervous system and HPA axis in children exposed to early-life deprivation associated with institutional rearing. Electrocardiogram, impedance cardiograph, and neuroendocrine data were collected during laboratory-based challenge tasks from children (mean age = 12.9 y) raised in deprived institutional settings in Romania randomized to a high-quality foster care intervention ( n = 48) or to remain in care as usual ( n = 43) and a sample of typically developing Romanian children ( n = 47). Children who remained in institutional care exhibited significantly blunted SNS and HPA axis responses to psychosocial stress compared with children randomized to foster care, whose stress responses approximated those of typically developing children. Intervention effects were evident for cortisol and parasympathetic nervous system reactivity only among children placed in foster care before age 24 and 18 months, respectively, providing experimental evidence of a sensitive period in humans during which the environment is particularly likely to alter stress response system development. We provide evidence for a causal link between the early caregiving environment and stress response system reactivity in humans with effects that differ markedly from those observed in rodent models.
Background
Though noted in the clinical literature for more than 50 years, attachment disorders have been studied systematically only recently. In part because of the ubiquity of attachments in ...humans, determining when aberrant behavior is best explained as an attachment disorder as opposed to insecure attachment has led to some confusion. In this selective review, we consider the literature on reactive attachment disorder and disinhibited social engagement disorder and describe an emerging consensus about a number of issues, while also noting some areas of controversy and others where we lack clear answers. We include a brief history of the classification of the disorders, as well as measurement issues. We describe their clinical presentation, causes and vulnerability factors, and clinical correlates, including the relation of disorders to secure and insecure attachment classifications. We also review what little is known and what more we need to learn about interventions.
Methods
We conducted a literature search using PubMed, PsycINFO, and Cochrane Library databases, using search terms ‘reactive attachment disorder,’ ‘attachment disorder,’ ‘indiscriminate behavior,’ ‘indiscriminate friendliness,’ ‘indiscriminate socially disinhibited reactive attachment disorder,’ ‘disinhibited social engagement disorder,’ and ‘disinhibited social behavior.’ We also contacted investigators who have published on these topics.
Findings
A growing literature has assessed behaviors in children who have experienced various types of adverse caregiving environments reflecting signs of putative attachment disorders, though fewer studies have investigated categorically defined attachment disorders. The evidence for two separate disorders is considerable, with reactive attachment disorder indicating children who lack attachments despite the developmental capacity to form them, and disinhibited social engagement disorder indicating children who lack developmentally appropriate reticence with unfamiliar adults and who violate socially sanctioned boundaries.
Conclusions
Although many questions remain to be answered, especially regarding appropriate interventions, we know considerably more about attachment disorders than we did only a decade ago.
Read the Commentary on this article at doi: 10.1111/jcpp.12373
Current frameworks for understanding the link between early adverse childhood experiences and later negative life outcomes, including psychopathology, focus on the mediating negative impact on brain ...and biological systems in the developing child resulting broadly from stress and trauma. Although this approach is useful, we argue that the framework could be functionally extended by distinguishing the effects of two different types of abnormal input, both deviations from the expectable environment in early childhood. Specifically, we review the consequences of inadequate input (eg, neglect/deprivation) and harmful input (eg, abuse/trauma) on brain and biological development. We then review evidence on the differential links between each type of abnormal input to four selected domains of psychopathology (indiscriminate social behavior, posttraumatic stress disorder, attention-deficit/hyperactivity disorder, and conduct problems), and consider potential mechanisms for inadequate and harmful input to lead to these outcomes. We conclude that the careful consideration of the type of deviation from the expected environment, while acknowledging the practical difficulties in assessing this, is likely to lead to clearer understanding of the mechanism of risk for psychopathology, and that tailored approaches to prevention and intervention may be informed by considering the unique consequences of inadequate and harmful input when experienced in early childhood.
In a randomized controlled trial, we compared abandoned children reared in institutions to abandoned children placed in institutions but then moved to foster care. Young children living in ...institutions were randomly assigned to continued institutional care or to placement in foster care, and their cognitive development was tracked through 54 months of age. The cognitive outcome of children who remained in the institution was markedly below that of never-institutionalized children and children taken out of the institution and placed into foster care. The improved cognitive outcomes we observed at 42 and 54 months were most marked for the youngest children placed in foster care. These results point to the negative sequelae of early institutionalization, suggest a possible sensitive period in cognitive development, and underscore the advantages of family placements for young abandoned children.
Experience plays an essential role in building brain architecture after birth. The question we address in this paper is what happens to brain and behavior when a young child is deprived of key ...experiences during critical periods of brain development. We focus in particular on the consequences of institutional rearing, with implication for the tens of millions of children around the world who from an early age experience profound psychosocial deprivation. Evidence is clear that deprivation can lead to a host of both short- and long-term consequences, including perturbations in brain structure and function, changes at cellular and molecular levels, and a plethora of psychological and behavioral impairments.
We used structural MRI and EEG to examine brain structure and function in typically developing children in Romania (n = 20), children exposed to institutional rearing (n = 29), and children ...previously exposed to institutional rearing but then randomized to a high-quality foster care intervention (n = 25). In so doing, we provide a unique evaluation of whether placement in an improved environment mitigates the effects of institutional rearing on neural structure, using data from the only existing randomized controlled trial of foster care for institutionalized children. Children enrolled in the Bucharest Early Intervention Project underwent a T1-eighted MRI protocol. Children with histories of institutional rearing had significantly smaller cortical gray matter volume than never-institutionalized children. Cortical white matter was no different for children placed in foster care than never-institutionalized children but was significantly smaller for children not randomized to foster care. We were also able to explain previously reported reductions in EEG α-power among institutionally reared children compared with children raised in families using these MRI data. As hypothesized, the association between institutionalization and EEG α-power was partially mediated by cortical white matter volume for children not randomized to foster care. The increase in white matter among children randomized to an improved rearing environment relative to children who remained in institutional care suggests the potential for developmental "catch up" in white matter growth, even following extreme environmental deprivation.
Background Children exposed to early-life psychosocial deprivation associated with institutional rearing are at markedly elevated risk of developing attention-deficit/hyperactivity disorder (ADHD). ...Neurodevelopmental mechanisms that explain the high prevalence of ADHD in children exposed to institutionalization are unknown. We examined whether abnormalities in cortical thickness and subcortical volume were mechanisms explaining elevations in ADHD among children raised in institutional settings. Methods Data were drawn from the Bucharest Early Intervention Project, a cohort of children raised from early infancy in institutions in Romania ( n = 58) and age-matched community control subjects ( n = 22). Magnetic resonance imaging data were acquired when children were aged 8 to 10 years, and ADHD symptoms were assessed using the Health and Behavior Questionnaire. Results Children reared in institutions exhibited widespread reductions in cortical thickness across prefrontal, parietal, and temporal regions relative to community control subjects. No group differences were found in the volume of subcortical structures. Reduced thickness across numerous cortical areas was associated with higher levels of ADHD symptoms. Cortical thickness in lateral orbitofrontal cortex, insula, inferior parietal cortex, precuneus, superior temporal cortex, and lingual gyrus mediated the association of institutionalization with inattention and impulsivity; additionally, supramarginal gyrus thickness mediated the association with inattention and fusiform gyrus thickness mediated the association with impulsivity. Conclusions Severe early-life deprivation disrupts cortical development resulting in reduced thickness in regions with atypical function during attention tasks in children with ADHD, including the inferior parietal cortex, precuneus, and superior temporal cortex. These reductions in thickness are a neurodevelopmental mechanism explaining elevated ADHD symptoms in children exposed to institutional rearing.
This study examined the validity of criteria for indiscriminately social/disinhibited and emotionally withdrawn/inhibited reactive attachment disorder (RAD).
As part of a longitudinal intervention ...trial of previously institutionalized children, caregiver interviews and direct observational measurements provided continuous and categorical data used to examine the internal consistency, criterion validity, construct validity, convergent and discriminant validity, association with functional impairment, and stability of these disorders over time.
As in other studies, the findings showed distinctions between the two types of RAD. Evidence-derived criteria for both types of RAD showed acceptable internal consistency and criterion validity. In this study, rates of indiscriminately social/disinhibited RAD at baseline and at 30, 42, and 54 months were 41/129 (31.8%), 22/122 (17.9%), 22/122 (18.0%), and 22/125 (17.6%), respectively. Signs of indiscriminately social/disinhibited RAD showed little association with caregiving quality. Nearly half of children with indiscriminately social/disinhibited RAD had organized attachment classifications. Signs of indiscriminately social/disinhibited RAD were associated with signs of activity/impulsivity and of attention-deficit/hyperactivity disorder and modestly with inhibitory control but were distinct from the diagnosis of attention-deficit/hyperactivity disorder. At baseline, 30, 42, and 54 months, 6/130 (4.6%), 4/123 (3.3%), 2/125 (1.6%), and 5/122 (4.1%) of children met criteria for emotionally withdrawn/inhibited RAD. Emotionally withdrawn/inhibited RAD was moderately associated with caregiving at the first three time points and strongly associated with attachment security. Signs of this type of RAD were associated with depressive symptoms, although two of the five children with this type of RAD at 54 months did not meet criteria for major depressive disorder. Signs of both types of RAD contributed independently to functional impairment and were stable over time.
Evidence-derived criteria for indiscriminately social/disinhibited and emotionally withdrawn/inhibited RAD define two statistically and clinically cohesive syndromes that are distinct from each other, shows stability over 2 years, have predictable associations with risk factors and attachment, can be distinguished from other psychiatric disorders, and cause functional impairment.
Children reared in institutions experience profound deprivation that is associated with both heightened levels of psychopathology and deficits in executive functioning (EF). It is unclear whether ...deficits in EF among institutionally-reared children serve as a vulnerability factor that increases risk for later psychopathology. It is also unclear whether this putative association between EF and psychopathology is transdiagnostic (i.e. cuts across domains of psychopathology), or specific to a given syndrome. Thus, we examined whether global deficits in EF mediate the association between severe childhood neglect and general v. specific psychopathology in adolescence.
The sample consisted of 188 children from the Bucharest Early Intervention Project, a longitudinal study examining the brain and behavioral development of children reared in Romanian institutions and a comparison group of never-institutionalized children. EF was assessed at age 8, 12, and 16 using a well-validated measure of neuropsychological functioning. Psychopathology was measured as general (P) and specific internalizing (INT) and externalizing (EXT) factors at age 12 and 16.
Institutionally-reared children had lower global EF and higher general psychopathology (P) at all ages compared to never-institutionalized children. Longitudinal path analysis revealed that the effect of institutionalization on P at age 16 operated indirectly through poorer EF from ages 8 to 12. No indirect effects involving EF were observed for INT or EXT at age 16.
We conclude that stable, global deficits in EF serve as a cognitive endophenotype that increases transdiagnostic vulnerability to psychopathology in adolescence among those who have experienced profound early neglect.
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