BDNF and post-traumatic stress disorder: In conclusion, this study shows that PTSD is a complex phenomenon for which, according to the final regression model proposed, risk factors include the presence of the Val66Met allele of the BDNF gene, S’S’ alleles of the 5-HTTLPR gene, the female sex, a family history of DEs, and experience of one or more forms of childhood maltreatment; OR = 1.87, 95% (CI: 1.57–2.24, p < 0.001).