In men, PTSD symptom severity at hospitalization but not follow-up trended significantly different with genotype at rs806371. Interestingly, individuals with at least one G at rs806371 and at least one A at rs323320 in FAAH had a significantly higher mean PTSD total score at follow-up (28.6 ± 22.4; n = 28) compared to those homozygous for the common alleles at both loci (14.2 ± 17.7; n = 57) (p = 0.002). This evidence concerns the gene FAAH and post-traumatic stress disorder.