Here, we report evidence from three independent studies demonstrating the a priori hypothesized GxE predicting youths' positive affect, consistent with the DSH's ‘for better and worse' conceptualization. In the first study, parents reported on the degree to which they use positive/supporting parenting. In the second study, parenting behaviors were observed in the laboratory. In the third study, positive parenting was operationalized as the emotional warmth perceived by the youth themselves. Positive affect was assessed using varying self reported questionnaires. Given well-known and publicized lack of replication in GxE research,33, 36 we tested this GxE hypothesis in three independent samples using multiple methods to assess environment input (that is, parenting) and positive affect. This consistent finding across the three studies suggests a robust effect that youth homozygous for the short allele of 5-HTTLPR exhibit differential susceptibility to experience positive affect as a function of parental positivity and support.
