5HTT genotype moderates the influence of early institutional deprivation on emotional problems in adolescence: evidence from the English and Romanian Adoptee (ERA) study

Background: A common polymorphism in the serotonin transporter gene (SLC6A4, 5HTT) has been repeatedly shown to moderate the influence of childhood adversity and stressful life events on the development of psychopathology. Using data from the English and Romanian Adoptee Study, a prospective-longitudinal study of individuals (n = 125) exposed to severe early institutional deprivation (ID), we tested whether the effect of ID on adolescent emotional problems is moderated by 5HTT genotype and stressful life events in adolescence. Methods: Emotional problems were assessed using questionnaire data (age 11), and on the basis of the CAPA diagnostic interview (age 15). Additionally, the number of stressful life events was measured. Results: There was a significant effect for genotype (p = .003) and a gene x environment interaction (p = .008) that was independent of age at testing. Carriers of the s/l and s/s genotype who experienced severe ID showed the highest emotional problem scores, while l/l homozygotes in the severe ID group showed the lowest overall levels. Furthermore, s/s carriers in the severe ID group who experienced a high number of stressful life events between 11 and 15 years had the largest increases in emotional problem scores, while a low number of stressful life events was associated with the largest decrease (4-way interaction: p = .05). Conclusions: The effects of severe early ID on emotional problems in adolescence are moderated by 5HTT genotype, and influenced by stressful life events in adolescence.