NR3C1 and post-traumatic stress disorder: Peripheral and central levels of corticotropin-releasing hormone, which represents the initiating step in the activation of the hypothalamic/pituitary/adrenal (HPA) axis, are elevated, and enhanced glucocorticoid negative feedback on the HPA axis is consistently reported; as a result, individuals with PTSD have elevated levels of the glucocorticoid receptor (GR), and enhanced glucocorticoid sensitivity [3].