The association between neuroticism and the serotonin transporter polymorphism depends on structural differences between personality measures

Over the last decade the relationship between the serotonin transporter polymorphism (5-HTTLPR) and anxiety related personality traits has been intensely investigated. Although there are some meta-analytic approaches, the question remains open why the results of these studies are inconsistent. One suggestion is, that structural differences between personality measures lead to this heterogeneity. Based on this assumption we investigated the relationship between the 5-HTTLPR and neuroticism (N) as measured by the EPQ-R and NEO-FFI as well as harm avoidance (HA) as measured by the TCI in a sample of N = 410 healthy Caucasians. There were significant main effects of the s-allele for the EPQ-R-N (F = 6.98; df = 1; p = 0.009) as well as for the NEO-FFI-N (F = 4.08; df = 1; p = 0.044), but not for HA. In order to detect which aspects of negative emotionality are essential for the association with the 5-HTTLPR, all items of the three scales were tested with respect to their relation to the 5-HTTLPR. The 12 items which were significantly associated with the 5-HTTLPR form a new scale with a high internal consistency (α = .84). With respect to the item contents it can be summarized that especially the components of depression and stress sensitivity relate to the transporter polymorphism.