Tryptophan hydroxylase 1 gene (TPH1) moderates the influence of social support on depressive symptoms in adults

Background phan hydroxylases (TPHs) are involved in the biosynthesis of serotonin and are therefore candidate genes for psychiatric disorders, including depression. We examined whether the common 218 A > C and 779 A > C polymorphisms in the tryptophan hydroxylase 1 gene (TPH1) moderated the association between perceived social support and sub-clinical depressive symptoms in adults. s bjects were a randomly selected subsample (n = 341) of individuals participating in the Cardiovascular Risk in Young Finns study, who had data on social support on one assessment time and depressive symptoms on two assessment times. Social support was assessed on the Perceived Social Support Scale Revised (PSSS-R) and depressive symptoms on a modified version of the Beckʹs Depression Inventory (BDI). s nd that low social support predicted depressive symptoms more strongly in individuals carrying A alleles of the TPH1 than in others. The interaction effect was observed in a cross-sectional analysis and when predicting depressive symptoms over a four-year period. tions not have data on TPH2, which has recently been identified as the primary TPH isomorphism affecting serotonin synthesis in the brain. sions ene may be involved in the development of depressive symptoms by moderating the impact of depressogenic social influences.