TPH1 and Borderline personality disorder: No associations between BPD traits and three serotonergic polymorphisms, two common polymorphisms of the serotonin transporter gene (SCL6A4), the promotor insertion/deletion (5-HTTLPR) and the intron 2 VNTR, or the rs1800532 polymorphism of the tryptophan hydroxylase 1 gene (TPH1) were found.