Short polymorphism of the serotonin transporter (5-HTTLPR) gene and its association with the cortisol stress response: a meta-analysis

Several studies have been conducted to analyze the role of short polymorphism of serotonin transporter (5-HTTLPR) in response to psychosocial stress mediated by cortisol, having found inconsistent results. In order to synthesize and analyze available information about the role of short polymorphisms of 5-HTTLPR gen in the stress response, this meta-analysis has been carried out. A meta-analysis of studies published until November 2011 without language restrictions, which analyzed the effect of the short polymorphisms of 5-HTTLPR in the cortisol response during a stress-inducing protocol was conducted. Published F or p genotype values were collected as estimators of the difference between groups as well as the sign of this difference for analysis. The global meta-analysis showed no significant association between the presence of the short allele and a different response to psychosocial stress. After comparing the subgroups of studies where participants underwent an emotionally neutral intervention versus an emotionally negative intervention, significant differences were found. The subgroup of studies where patients underwent an emotionally negative intervention showed a significantly greater cortisol release by those individuals carrying the short allele. This association was not seen in the neutral subgroup.