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.
aDivision of Substance Dependence, Department of Psychiatry, University of Colorado School of Medicine, Denver
bInstitute for Behavioral Genetics, University of Colorado at Boulder, Boulder, Colorado
cIrvine College of Health Sciences, University of California, Irvine, California, USA
Correspondence to Joseph Sakai, MD, Division of Substance Dependence, Department of Psychiatry, University of Colorado School of Medicine, 4200 East Ninth Avenue, Box C268-35, Denver CO 80262
Tel: +1 303 315 1516; fax: +1 303 315 0394;
Received 1 February 2006 Accepted 15 December 2006