Background: We tested the hypothesis that a functional biallelic repetitive element in the 5' regulatory region of the human serotonin transporter gene (SLC6A4) confers susceptibility to serotonin-related personality traits underlying alcohol dependence with dissocial behavior.
Methods: The association study was focused on 64 alcohol-dependent subjects with a dissocial personality disorder (according to ICD-10) who were derived from 315 German alcohol-dependent subjects. The Tridimensional Personality Questionnaire (TPQ) was applied to assess personality dimensions in 101 alcohol-dependent men, including 39 dissocial alcoholics.
Results: Our association analyses revealed a trend towards a higher frequency of the short (S) allele of the SLC6A4 polymorphism in dissocial alcoholics compared to 216 German controls (chi 2 = 2.81, df = 1, p = 0.094). Dissocial alcoholics carrying the S/S genotype exhibited significant lower scores of harm avoidance compared to those lacking it (U-test, p = 0.015). Significantly higher novelty seeking scores were obtained in dissocial alcoholics carrying the S allele relative to those lacking it (U-test, p = 0.021).
Conclusions: Our tentative association findings in dissocial alcoholics suggest that the S allele of the 5' regulatory SLC6A4 polymorphism confers susceptibility to a temperamental profile of high novelty seeking and low harm avoidance that has been postulated to underlie dissocial (type-2) alcoholism according to Cloninger's neurogenetic theory of personality.