FKBP5 and post-traumatic stress disorder: Of particular relevance for the current study, changes in DNA methylation at the promoter region of FKBP5 have also been implicated in response to exposure therapy in veterans with post‐traumatic stress disorder (PTSD) (Yehuda et al., 2013), with decreases in region‐specific DNA methylation across the course of therapy associated with better response and increases with poorer response.