In smokers and non-smokers with PTSD, no significant differences in the ROCF delayed recall test scores between carriers of BDNF rs56164 genotypes (H = 2.124; df = 2; p = 0.346 for smokers and H = 2.806; df = 2; p = 0.246 for non-smokers), T vs. CC genotype carriers (U = 123.5; p = 0.167 for smokers and U = 43.0; p = 0.766 for non-smokers), and alleles (U = 321.0; p = 0.199 for smokers and U = 118.0; p = 0.721 for non-smokers) was detected. This evidence concerns the gene BDNF and post-traumatic stress disorder.