MAOA and post-traumatic stress disorder: The present observation of non-response to CBT to be accompanied by a further decrease in MAOA methylation underlines some reports of temporary symptom exacerbation during exposure therapy, for example, in a minority of patients with post-traumatic stress disorder particularly when only considering the very early-treatment stages, for example refs. 34 and 35, and suggests MAOA methylation dynamics as a potential epigenetic correlate.