To test whether genotype of the serotonin transporter-linked polymorphic region (5HTTLPR
) and atypical attachment interact to predict externalizing
psychopathology prospectively in a sample of children with a history of early institutional care.
Caregiver report of externalizing
behavior at 54 months was examined in 105 children initially reared in institutional care and enrolled in the Bucharest Early Intervention Project, a randomized controlled trial of high quality foster care. 5HTTLPR
genotype, attachment status at 42 months of age (typical [secure, avoidant, or ambivalent] or atypical [disorganized-controlling, insecure-other]), and their interaction were examined as predictors of externalizing
behavior at age 54 months.
genotype and atypical attachment at age 42 months interacted to predict externalizing
behavior at age 54 months. Specifically, children with the s/s
genotype with an atypical attachment had the highest externalizing
scores. However, s/s
children with a typical attachment demonstrated the lowest externalizing
scores, even after controlling for intervention group status. There was no association between attachment status and externalizing
behavior among children carrying at least 1 copy of the l
These findings indicate that genetic variation in the serotonergic system moderates the association between atypical attachment status and externalizing
in young children. Our findings suggest that children, as a result of genetic variability in the serotonergic system, demonstrate differential sensitivity
to the attachment relationship.