In line with this, in non-smokers with PTSD, ROCF copy test scores did not differ significantly between BDNF rs56164415 genotype carriers (H = 0.410; df = 2; p = 0.815), T vs. CC genotype carriers (U = 42.0; p = 0.522) or T and C allele carriers (U = 116.0; p = 0.464). Here, BDNF is linked to post-traumatic stress disorder.