But some children do not find themselves in the care of a family but rather in the care of an institution. There they are much more likely to experience a lack of responsive and sensitive care. We now know that growing up in such settings has a long-term negative impact on a child’s physical and mental health.
Important questions remain about how best to help children recover from the negative effects of being institutionalised. Research with rodents and non-human primates has provided some clues. These animal studies have demonstrated that early maternal deprivation has enduring effects on biological and behavioural responses to stress, such as the functioning of the hyperthalamic-pituitary-adrenal (HPA) axis, a key physiological system that regulates stress hormone production.
It has also been shown that a typically high stress response of rodents who have been maternally deprived can be reversed by an enriched environment during puberty. However, because of the differences between animals and humans, it hasn’t been possible to generalise from animal studies to humans.
Turning down the stress levels
A new US study published in Proceedings of the National Academy of Sciences examined the consequences of early life deprivation on children associated with growing up in an institution. The study, by scientists based at the University of Washington, also looked at the potential for a family caregiving environment to reverse the impact of such early adversity.
The children in the study were abandoned in Romania. They were randomly selected with 43 remaining in institutions in Bucharest and 48 placed in foster family care. These two groups of children were compared with each other and also with another group of 47 children who came from similar backgrounds, but had never been institutionalised.
The scientists measured the impact of these different rearing conditions on the development of the children’s “stress response system”. They did this by measuring the autonomic nervous system and the HPA axis. Because the institutionalised children were placed in foster care at different ages, it was possible to investigate the impact of timing on the development of their “stress response system”.
The researchers found that children who remained in institutional care exhibited significantly blunted biological response to psychosocial stress compared with children who were in foster care. In other words, their stress response systems responded less strongly to a socially challenging task. Overall, children in foster care generally resembled the typically developing children who had never been institutionalised.
These findings provide convincing evidence that the disruption to early caregiving among children who have experienced institutional care can have a negative impact on children’s response to stress later on. However, it is extremely encouraging that by placing children in the care of a foster family, the effects of such early institutionalisation on stress systems can be ameliorated. It will be important to show in future studies that there are also improvements in behaviour and emotional functioning.
The researchers also found that the therapeutic effects of the foster care were most evident in children who were fostered before they reached 24 months. They fared much better. For example, the reactivity of the stress hormone, cortisol, was significantly associated with the age of being placed in foster care: the earlier the foster placement the more normal the cortisol response to stress at the age of 12.
The authors have previously found that such timing effects have a similar impact on other domains, including attachment. Collectively, these findings lend weight to the notion that there are sensitive periods in human development when it comes to caregiving.
As with any study, there are a number of factors that need to be weighed up when considering the implications of the research. The random allocation of children to foster care or institutional care makes it more likely that both groups were as similar as possible. However, it is less clear why children in the fostered group were placed with families earlier or later. It’s possible the most difficult children who had experienced the most adversity were placed later. If so this would weaken a strong argument for a sensitive period.
A second issue to consider is that that stress response systems may reflect the current environmental demands of where a child is placed. We know that some of these children still remain in the institutions. It remains possible that stress responses could, at least in part, be “recalibrated” by foster care placement – even as these children are entering adolescence – given that this represents a period of particular neurobiological plasticity during which certain brain regions undergo a process of rewiring.
These findings have important implications for policy and practice for