Lack of association between the serotonin transporter promoter polymorphism (5-HTTLPR) and personality traits in asymptomatic patients with panic disorder

The serotonin transporter promoter polymorphism (5-HTTLPR) has been investigated regarding its association with neuroticism, which, in its turn, is a personality dimension often found in patients with panic disorder (PD). It has been recently evidenced that the long 5-HTTLPR polymorphism has a genetic variation (Lg), which is related to its lower expression. The objective of this study was to assess the association between the 5-HTTLPR polymorphism in the triallelic system and the neurotic personality traits in patients in PD remission. Sixty-seven Caucasian patients with PD diagnosis according to the DSM-IV-TR assessed with the MINI (mini international neuropsychiatric interview) were included. The MMPI (Minnesota multiphasic personality inventory) was used to assess the personality. The remission of PD symptoms was defined as CGI (clinical global impression) ≤2 and absence of panic attacks. The patients' genotypes were grouped according to the level of expression: low expression (SS, SLg and LgLg), intermediate expression (SLa, LgLa) and high expression (LaLa). There was no significant deviation from Hardy-Weinberg equilibrium (χ2 = 0.52, d.f. = 1, p = 0.471). According to the triallelic classification, the distribution of alleles in these patients was as follows: S 58 (43.3%), Lg 17 (12.7%) and La 59 (44.0%). There were no significant differences on the MMPI scales between different genotype classifications and allele analyses. Larger samples are necessary to exclude the less relevant genetic influences on these traits. In addition, other polymorphisms should be considered in the characterization of a heritable phenotype in the PD.