Association between a serotonin transporter promoter polymorphism (5HTTLPR) and personality disorder traits in a community sample

Background: The serotonin transporter (SERT) polymorphism (5HTTLPR) has been reported to be associated with several psychiatric conditions. Specific personality disorders could be intermediate factors in the known relationship between 5HTTLPR and psychiatric disorders. This is the first study to test the association between this polymorphism and dimensions of all DSM-IV personality disorders in a community sample. Methods: 374 white participants were assessed by clinical psychologists using the International Personality Disorder Examination (IPDE). Associations between dimensions of each DSM-IV personality disorder and the long (l) and short (s) alleles of the 5HTTLPR were evaluated using non-parametric tests and regression models. Results: The s allele of the 5HTTLPR polymorphism was significantly associated with higher avoidant personality trait scores in the whole sample. Males with the s allele had a significantly lower likelihood of higher obsessive-compulsive personality disorder (OCPD) trait scores, whereas females with the s allele were likely to have higher OCPD personality trait scores. Conclusion: This paper provides preliminary data on the relationship between personality disorders and the 5HTTLPR polymorphism. The relationship of the s allele and avoidant PD is consistent with findings of a nonspecific relationship of this polymorphism to anxiety and depressive disorders. Concerning the unusual sexual dimorphic result with OCPD, several hypotheses are presented. These findings need further replication, including a more detailed study of additional variants in SERT.