Background: Evidence has indicated that BDNF (brain-derived neurotrophic factor) Val66Met genetic variant could be linked to the development of posttraumatic stress disorder (PTSD). However, clinical observations studying the BDNF polymorphism and the risk of PTSD yielded contradictory results. In this meta-analysis we evaluated the association between BDNF Val66Met and PTSD risk. Method: Systematic searches in online databases retrieved 6 relevant publications. Different inherited models were utilized to perform the pooled analysis. Subgroup analyses and sensitive analyses based on Hardy-Weinberg equilibrium (HWE) test results were also carried out. Results: Our study did not found a significant overall effect of BDNF Val66Met on the susceptibility to PTSD under various genetic models. In contrast, subgroup analyses suggested that the stress status of the control group, but not ethnicity, may influence the relationship of BDNF Val66Met with PTSD risk. After the exclusion of a study that was not in HWE, our conclusions remained unchanged during the influence analyses. Conclusions: This meta-analysis suggested no genetic association of BDNF Val66Met with vulnerability to PTSD. Further research studies are warranted to clarify the impact of BDNF variants on the occurrence of PTSD.

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