Elizabeth K Wood1, Whitney F Espinel1, Jacob Hunter1, Alexa Emmett1, Andrea N Skowbo1, Melanie L Schwandt2, Courtney Shannon3, Stephen G Lindell4, Christina S Barr4, Stephen J Suomi5, J Dee Higley6. 1. Brigham Young University, Provo, Utah. 2. Laboratory of Clinical Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland. 3. Section of Comparative Behavioral Genomics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland. 4. Laboratory of Clinical Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland; Section of Comparative Behavioral Genomics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland. 5. Section of Comparative Ethology, Eunice Shriver Kennedy National Institute of Child Health and Human Development, National Institutes of Health, Poolesville, Maryland. 6. Brigham Young University, Provo, Utah. Electronic address: james_higley@byu.edu.
Abstract
OBJECTIVE: Adopted children tend to show an increased risk for a variety of psychopathological outcomes, even when adoption occurs at birth, which some suggest is a result of nonrandom assignment of adoptees and parents. This study uses a nonhuman primate model, in which adoptions were randomly assigned, to investigate the behavioral and physiological outcomes associated with at-birth adoption. METHOD: Immediately following birth, rhesus monkey infants were randomly assigned to be reared by either their biological mother (n = 113) or by an unrelated, lactating, adoptive mother (n = 34). At 6 months of age, infant behavior and physiology were assessed during a stressful series of mother-infant separations. Four years later, stress-related behaviors were measured following confrontation by an unfamiliar intruder, an ecologically meaningful stressor. RESULTS: When compared to infants reared by their biological mothers, adopted infants exhibited more behavioral withdrawal and higher plasma adrenocorticotropic hormone (ACTH) concentrations in response to separation. These behavioral differences persisted 4 years later during a stressful intruder challenge, with adoptees exhibiting more behavioral withdrawal, stereotypies, and impulsive approaches of the potentially aggressive intruder. CONCLUSION: Compared to infants reared by their biological mothers, adopted infants exhibited more behavioral inhibition, impulsivity, and higher ACTH concentrations, even when subjects were randomly assigned to be adopted or to remain with their biological mother. To the extent that these findings generalize to humans, they suggest that the overall risk for psychopathology in adopted individuals persists even after random assignment to adoption conditions.
OBJECTIVE: Adopted children tend to show an increased risk for a variety of psychopathological outcomes, even when adoption occurs at birth, which some suggest is a result of nonrandom assignment of adoptees and parents. This study uses a nonhuman primate model, in which adoptions were randomly assigned, to investigate the behavioral and physiological outcomes associated with at-birth adoption. METHOD: Immediately following birth, rhesus monkey infants were randomly assigned to be reared by either their biological mother (n = 113) or by an unrelated, lactating, adoptive mother (n = 34). At 6 months of age, infant behavior and physiology were assessed during a stressful series of mother-infant separations. Four years later, stress-related behaviors were measured following confrontation by an unfamiliar intruder, an ecologically meaningful stressor. RESULTS: When compared to infants reared by their biological mothers, adopted infants exhibited more behavioral withdrawal and higher plasma adrenocorticotropic hormone (ACTH) concentrations in response to separation. These behavioral differences persisted 4 years later during a stressful intruder challenge, with adoptees exhibiting more behavioral withdrawal, stereotypies, and impulsive approaches of the potentially aggressive intruder. CONCLUSION: Compared to infants reared by their biological mothers, adopted infants exhibited more behavioral inhibition, impulsivity, and higher ACTH concentrations, even when subjects were randomly assigned to be adopted or to remain with their biological mother. To the extent that these findings generalize to humans, they suggest that the overall risk for psychopathology in adopted individuals persists even after random assignment to adoption conditions.
Authors: Melanie L Schwandt; Stephen G Lindell; Rickard L Sjöberg; Kelli L Chisholm; J Dee Higley; Stephen J Suomi; Markus Heilig; Christina S Barr Journal: Biol Psychiatry Date: 2009-12-16 Impact factor: 13.382