Association between the TPH1 A218C polymorphism and antidepressant response: evidence from an updated ethnicity, antidepressant-specific, and ethnicity-antidepressant interaction meta-analysis.

BACKGROUND: Several studies have investigated the potential association between genetic polymorphisms of tryptophan hydroxylase 1 (TPH1) and antidepressant response. However, the results are inconsistent and inconclusive. Our aim was to assess the association of the TPH1 A218C polymorphism (rs1800532) with antidepressant response using ethnicity, antidepressant-specific, and ethnicity-antidepressant interactions in an updated meta-analysis. PATIENTS AND METHODS: Data were collected from the related literature published before December 2013 from MEDLINE and EMBASE databases. The meta-analysis was stratified by ethnicity, antidepressants, and ethnicity-antidepressant interaction, and was carried out using a random-effects model as appropriate using the Stata Statistical Package (version 11.0). RESULTS: A total of 12 individual studies and the STAR*D study were identified in the current study, among which six studies and the STAR*D study (White part) reported on the TPH1 A218C polymorphism and antidepressant response in a White population, with 2035 cases, and six studies and the STAR*D study (Asian part) were carried out in an Asian population, with 707 cases. In terms of the classes of antidepressants, eight studies and the STAR*D study explored this relationship using selective serotonin reuptake inhibitors (SSRIs) and four studies used other/mixed antidepressants. We found that the TPH1 A218C genotype was not significantly associated with antidepressant response either in all populations or in White and Asian populations. Moreover, the results did not change according to an ethnicity-antidepressant interaction model either in White populations using SSRIs or other/mixed antidepressants or in Asian populations. CONCLUSION: The TPH1 A218C polymorphism may not be associated with antidepressant response either in an ethnicity, antidepressant-specific population or in an ethnicity-antidepressant interaction model.