As demonstrated in Fig. 2, within the context of PTSD, glucocorticoid signalling is dysregulated and the HPA axis negative feedback loop is inhibited, resulting in increased corticotropin-releasing hormone (CRH) release but blunted adrenocorticotropic hormone (ACTH), resulting in diminished secretion of cortisol [31]. This evidence concerns the gene POMC and post-traumatic stress disorder.