Growing evidence suggests that early social deprivation impacts the activity of the hypothalamic-pituitary-adrenocortical axis. Early adverse care in the form of institutional or orphanage care provides a human model for early social deprivation. The present study examined changes in diurnal cortisol during the transition to family care in the first 2 years post-adoption. Children adopted between 15 and 36 months from institutional care were examined four times during their first 2 years post-adoption (N=. 58). Comparison groups included same-aged peers reared in their birth families (N=. 50) and children adopted during their first year from overseas foster care (N=. 47). Children provided daily cortisol samples at roughly 2, 9, 17, and 25 months post-adoption. Post-institutionalized and post-foster care children exhibited less steep diurnal cortisol compared to non-adopted same-aged peers; these differences did not diminish across the 2 year period. For post-institutionalized children, lower social care quality in institutions was associated with less steep cortisol slopes. Lastly, shallower diurnal cortisol was a mediator between adoption status and increased behavioral problems 2 years post-adoption. Consistent with the non-human primate literature, early social deprivation may contribute to early programming of the HPA axis.
Bibliographical noteFunding Information:
The authors would like to thank the other members of the Minnesota International Adoption Team for their efforts in collecting these data: Shanna Mliner, Kristin Frenn, Meg Bale, Bao Moua, and Sarah Stellern. We would also like to thank the parents and children without whom this study would not have been possible. This work was supported by grants R01 MH080905 and P50 MH078105 from the National Institute of Mental Health awarded to Megan Gunnar. Support was provided to Kalsea Koss by a National Institute of Mental Health training grant ( T32 MH015755 ) during the preparation of this article.
© 2014 Elsevier Ltd.
- Early adversity
- Early childhood
- International adoption
- Problem behavior
- Social deprivation