There was a significant COMT × BDNF interaction effect on scores of active coping style (F = 4.43, P = 0.04) in all participants, irrespective of PTSD diagnosis, which was driven by the lower score in the COMT Met-BDNF Val/Val subgroup than the COMT Met-BDNF Met subgroup (P = 0.05), whereas no significant difference was found between COMT Val/Val-BDNF Val/Val and COMT Val/Val-BDNF Met subgroups (P = 0.20). The gene discussed is BDNF; the disease is post-traumatic stress disorder.