Abstract
Variation at the DRD4 locus has been postulated to be associated with a wide range of personality traits and psychopathologies. Most notably, the association between the 7-repeat allele of the exon-3 VNTR and ADHD is one of the most replicated findings in psychiatric genetics. Whilst considerable work has been done on DRD4 in small clinical samples, the relationship between alleles of this gene and quantitative measures of behaviour in a large population-based sample have never been studied. We have genotyped participants in the Dunedin Multidisciplinary Health and Development Study, a 26-year longitudinal study of a phenotypically well-characterised birth cohort (N=1037) for the 48 bp VNTR in exon 3 of DRD4. Our findings play down the role of DRD4 in hyperactivity, but support an association with quantitative and categorical measures of alcoholism as well as negative emotionality personality traits. We are currently replicating these findings in another large population-based sample comprising of 3000 twin pairs.