Neuroendocrine dysregulation following early social deprivation in children

Abstract

Human and non-human animal studies reveal that early experiences with caregivers shape children's ability to regulate their responses to stress. To understand the effects of early deprivation on the regulation of the hypothalamic-pituitary-adrenal axis following social interactions, we examined urinary cortisol levels in a group of internationally adopted children who had experienced institutional care, and thus, species-atypical attachment relationships, early in life prior to adoption. Cortisol regulation was assessed both basally and following standardized interpersonal interactions between the child and his/her mother and the child and an unfamiliar adult. Post-institutionalized children showed prolonged elevations in cortisol levels following the mother, but not the stranger, interaction. More severe neglect was associated with the highest basal cortisol levels and the most impaired cortisol regulation following the mother interaction. These results suggest that early social deprivation may contribute to long-term regulatory problems of the stress-responsive system, and that these differences are most evident within the context of ongoing, close interpersonal relationships.

Causal effects of the early caregiving environment on development of stress response systems in children

“…This pervasive pattern of stress response system hyporesponsivity is inconsistent with patterns observed in the rodent literature following maternal deprivation (1)(2)(3)46) and challenges some prevailing conceptual models of early-life adversity and stress response system development, which argue that adverse environments should lead to elevated physiological reactivity (47,48). The observed pattern of cortisol hyporesponsivity is consistent with several prior studies in humans documenting an association between early-life deprivation and low levels of morning cortisol and blunted cortisol responses to social challenge (20,28,32), although other work has found elevated basal cortisol and heightened cortisol reactivity in children who have experienced social deprivation (17,27). The experimental design of the current study clarifies these inconsistencies in prior observational studies.…”

“…Some studies document hyperreactivity of the SNS and HPA axis following early-life adversity (15)(16)(17)(18)(19) and others observe blunted HPA axis reactivity (20)(21)(22) or discordance between SNS and HPA axis responses (23). Reconciling these inconsistencies has proved challenging for several reasons.…”

“…Reconciling these inconsistencies has proved challenging for several reasons. First, there is considerable heterogeneity in the type, frequency, severity, and cooccurrence of early-life adversities in human studies, including both abuse and neglect (15,18,19,21,22), poverty (24-26), institutional rearing followed by international adoption (17,20,27,28), or accumulation of multiple adversities, ranging from marital conflict to parental psychopathology (29)(30)(31). These exposures not only differ widely from each other, they also vary in their resemblance to the exposure used in animal studies: maternal deprivation.…”

“…These exposures not only differ widely from each other, they also vary in their resemblance to the exposure used in animal studies: maternal deprivation. Lower morning cortisol and blunted cortisol reactivity are the most commonly reported patterns in studies of maternal deprivation related to neglect or institutional rearing following by international adoption (20,28,32), although elevated basal cortisol and cortisol reactivity have also been observed (17,27). Second, existing human research has been unable to identify causal effects of the rearing environment on stress response system development.…”

Evidence of a unique and common genetic etiology between the CAR and the remaining part of the diurnal cycle: A study of 14 year-old twins

“…Diurnal cortisol secretion has been associated with personal traits, such as optimism (Jobin et al, 2014) and fearfulness . Diurnal secretion has also been linked to early adverse experiences, such as maltreatment and neglect (Cicchetti et al, 2010;Fries et al, 2008;Tarullo and Gunnar, 2006). Similar findings are also emerging in regards to peer victimization in adolescence (Ouellet-Morin et al, 2011a;Ouellet-Morin et al, 2011b;Vaillancourt et al, 2008), reflecting the sensitive nature of HPA axis activity to changing social environments.…”