CRH and post-traumatic stress disorder: In addition, we explored whether methylation levels of two other genes within the stress hormone system (NR3C1 and FKBP5), previously shown to predict and correlate with PTSD symptom improvement after psychotherapy [22], would also be associated with pharmacological treatment response in our study, again with specific focus on patients with probable CRF system hyperactivity (rs110402 GG-carriers and exposure to child abuse).