Background: Several recent studies have reported an association between the serotonin transporter 5HTTLPR (s-allele) and aggression; however, nonreplications have also been reported. Inconsistencies may be explained by gene–environment interactions. Using a large general population sample, we sought to test for an association between 5HTTLPR and conduct problems, and to explore for a possible 5HTTLPR by maltreatment interaction.
Methods: Using Caucasian adolescents from the genetic-pairs sample of the National Longitudinal Study of Adolescent Health (n=1736), we tested for an association between 5HTTLPR and both a categorical and, separately, a continuous measure of conduct problems using regression analyses while controlling for sex, family effects, and age. We then tested for an association between 5HTTLPR and conduct problems using the within-family test Quantitative Transmission Disequilibrium Test. Analyses were repeated for a measure of adolescence-limited delinquency.
Results: Results did not support an association between 5HTTLPR and conduct problems or delinquency. The Quantitative Transmission Disequilibrium Test analyses, which account for population stratification, were nonsignificant (F=0.17; P=0.68); introducing maltreatment as a covariate into the model did not affect this association (F=0.17; P=0.68). No association was seen between 5HTTLPR and a measure of adolescence-limited delinquency (F=0.54; P=0.46).
Discussion: Using two methods in a large general population sample we did not find a significant association between 5HTTLPR and conduct problems. A gene by maltreatment interaction was not supported.