Gene-Environment Interplay in a Family and Neighborhood Context

Studies of human molecular genetics and social environment interactions on health have relied heavily on the classic diathesis-stress model that treats genetic variations and environments as being either risky or protective thereby diminishing the interactive space. We attempt to expand this space by 1) combining two polymorphisms (5-HTTLPR and STin2 VNTR) of the serotonin transporter gene (5-HTT) and 2) using a less truncated measure of the environment—socioeconomic status (SES). We find evidence of significant gene-environment interplay between the two 5-HTT polymorphisms and SES on depression in the first year after the birth of the child. More crucially, we find evidence that some people are genetically more or less reactive to the environment, resulting in a crossover of risks of PPD for the most reactive groups.