Association between anxiety traits and 5HTTLPR, negative results

The purpose of this study was to investigate a previously reported relationship between the serotonin transporter (5HTT) Linked Polymorphic Region (5HTTLPR) and anxiety as a personality trait (Lesch et al., 1996; Ricketts et al., 1998; Frazer et al., 1999). Two different personality inventories were used; one was the Eysenck Personality Questionnaire and the other, Cloninger's Temperament and Character Inventory. Neuroticism and Harm Avoidance were respectively chosen as anxiety phenotypic markers. Personality trait variability was matched to the polymorphisms of the 5HTTLPR. This study comprised 335 subjects, who were Argentinean University students, mean age 23 of both sexes. In spite of this large sample size, the previously reported association of anxiety related traits was not found. This raises questions about the significance of previous studies. However, this study differed in that the subjects were considerably younger than those of a previous study (Ricketts et al., 1998). Indeed, in a smaller study of elderly subjects, a significant influence of the 5-HTTLPR genotype on Harm Avoidance behavior was found (Ricketts et al., 1998). In that study it was proposed that the influence of this functional gene variant was greater in later life. The current study indirectly supports this hypothesis.