Introduction: Several studies have focused on the role of the 5HTTLPR polymorphism of the serotonin transporter gene in the background of affective and anxiety disorders. Results have indicated that the presence of the s allele of this gene is associated with neuroticism, affective and anxiety disorders. Less attention has been paid to the relationship of this polymorphism with a tendency for depression and anxiety within a healthy population.
Methods: We investigated the association of 5HTTLPR and a tendency for depression and anxiety in 102 psychiatrically healthy females. Each subjects completed the Zung Self-rating Depression Scale (ZSDS) and the Spielberger State-Trait Anxiety Inventory (STAI). All subjects were genotyped for 5HTTLPR by PCR. Psychometric scores of the three genotype groups (ss, sl and ll) and the two phenotype groups (subjects carrying the s allele vs. subjects not carrying the s allele) were compared using analysis of variance.
Results: Subjects carrying the s allele scored significantly higher on all three scales than subjects not carrying the s allele. Comparing the three genotype groups, on the ZSDS ss and sl subjects scored significantly higher than ll subjects. On the state anxiety scale subject carrying the sl genotype had a significantly higher score than subjects carrying the ll genotype.
Conclusion: Our results indicate that even in a psychiatrically healthy population there is an association between 5HTTLPR and a tendency for depression and anxiety or subclinical manifestation of depressive and anxiety symptoms. Identifying the genetic correlates of personality traits can lead to the identification of so-called endophenotypes, characteristics which can be associated with disorders and correspond to specific biochemical measures, which could be useful in delineating the genetic background of psychiatric disorders as well.