Psychological vulnerability differences in students--carriers or not of the serotonin transporter promoter allele S: effect of adverse experiences.

AIM

To study the effect of the serotonin transporting gene L/S polymorphism on several psychological characteristics in a group of Greek University students.

METHODS

One hundred eighty-one students were genotyped and classified into two groups: carriers or noncarriers of an S allele. Students were evaluated with a battery of psychological tests (Zung depression rating scale, symptoms check-list-90-R, Eysenck personality inventory); they also answered questionnaires regarding serious past adverse experiences as well as nicotine and alcohol use. Multivariate analysis of variance (MANOVA) was used to check the main effect of genotype and its interaction with both adverse life experiences and scores of psychological tests.

RESULTS

No significant differences were detected between the two groups of students regarding scores of the psychological tests. Yet, analysis with MANOVA indicated an interaction between genotype and adversities (lambda = 0.838, F(17,158) = 1.802, P = 0.032). Students who both carry at least one S allele and have faced serious past adverse life experiences have scored higher than carriers of the S allele who have not faced adversities on the following: global severity index (F(1174) = 5.973, P = 0.016), positive symptoms distress index (F(1174) = 4.518, P = 0.035), somatization (F(1174) = 4.074, P = 0.045), depression (F(1174) = 4.971, P = 0.027), anxiety (F(1174) = 8.112, P = 0.005), phobic anxiety (F(1174) = 16.421, P < 0.000), and paranoid ideation (F(1174) = 5.143, P = 0.025). Among students without adversities, those with the LL genotype have scored higher than S allele carriers on the following: depression (t = 2.680, df = 75, P = 0.009), anxiety (t = 2.629, df = 75, P = 0.010), phobic anxiety (t = 3.350, df = 75, P = 0.001), and paranoid ideation (t = 2.668, df = 75, P = 0.009).

CONCLUSION

The S and L alleles seem to interact differently with serious past life adversities in influencing psychological vulnerability. Adversities seem to have a stronger effect on S carriers. LL genotype might be related to the expression of certain more endogenous psychopathological tendencies.