The SS genotype of the bi-allelic 5-HTTLPR was associated with neuroticism in men.
When combining the rs25531 (tri-allelic approach), the association became stronger.
Men with the tri-allelic S′S′ genotype also had higher anxiety/depression scores.
Women showed a non-significant pattern across both the 5-HTTLPR classifications.
Our data provide further support for rs25531 strengthening the effects of 5-HTTLPR.