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


METHODS
The subjects 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 Beck's Depression Inventory (BDI).


RESULTS
We found 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.


CONCLUSIONS
We did not have data on TPH2, which has recently been identified as the primary TPH isomorphism affecting serotonin synthesis in the brain.


CONCLUSIONS
TPH1 gene may be involved in the development of depressive symptoms by moderating the impact of depressogenic social influences.
Jokela
Markus
M
Department of Psychology, University of Helsinki, Finland.
Räikkönen
Katri
K
Lehtimäki
Terho
T
Rontu
Riikka
R
Keltikangas-Järvinen
Liisa
L
D000328:Adult; D000483:Alleles; D003863:Depression / Q000235:genetics* / Q000523:psychology*; D004777:Environment; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D007438:Introns / Q000235:genetics; D008297:Male; D011110:Polymorphism, Genetic / Q000235:genetics; D012944:Social Support; D011795:Surveys and Questionnaires; D014365:Tryptophan Hydroxylase / Q000235:genetics*
C497467:TPH1 protein, human; D014365:Tryptophan Hydroxylase