Background: Personality traits have shown considerable heritable components. Association between alleles of a polymorphism in the third exon of the dopamine D4 receptor gene (DRD4) and the personality trait Novelty Seeking has been reported. Recently, in a sample of Swedish non-psychiatric subjects we could not detect any significant relationships between the same polymorphism and Novelty Seeking related scales in the Karolinska Scales of Personality (KSP). However, there was a tendency in the direction of the proposed association. There were also tentative associations between an exon I 13 bp deletion polymorphism and the personality traits Socialization and Guilt.
Methods: We investigated a new Swedish population-based sample (N = 167) investigated with the KSP for three DRD4 polymorphisms.
Results: Neither of the previous results were replicated. Combining the previous and the present samples did not give rise to any significant association between DRD4 polymorphisms and personality scales.
Conclusions: The dopamine D4 receptor gene is probably not of importance to the different personality dimensions as measured by the Karolinska Scales of Personality.