The association of monoamine-related gene polymorphisms with behavioural correlates of response inhibition: A meta-analytic review

Response inhibition has been shown to be associated with monoamine-related gene polymorphisms, although evidence is inconclusive. To comprehensively examine these genotype effects on behavioural correlates of response inhibition in non-clinical adult populations, we performed a two-step approach. A systematic review of studies using Go/No-Go and/or Stop-Signal paradigms was first carried out. Thirty-eight eligible research articles were identified, which examined over 15 candidate genes. Remarkably, no firm conclusions could be drawn from these studies. Thus, in a second step, we conducted meta-analyses using random effects models on those polymorphisms that had previously been investigated in at least three studies. Specifically, data from 11 studies was analysed in three meta-analyses for the following polymorphisms: SLC6A3 3′UTR VNTR (k = 6 samples; n = 1463 participants), COMT Val158Met SNP (k = 7 samples; n = 784) and SLC6A4 5-HTTLPR (k = 4 samples, n = 204). None of these polymorphisms showed a reliable association with response inhibition performance. The methodological and theoretical implications of these findings are discussed, along with recommendations for future research.