Using overnight metyrapone and combined dexamethasone/metyrapone tests, hypothalamic-pituitary-adrenocortical (HPA) axis feedback regulation was characterised in 10 patients with post-traumatic stress disorder (PTSD) and 10 matched healthy comparison subjects. Significant treatment effects of both metyrapone and the combination of dexamethasone and metyrapone were observed for adrenocorticotropic hormone (ACTH), 11-deoxycortisol (11-DOC) and cortisol, but no differences between patients and comparison subjects emerged. Dose-response studies using metyrapone and glucocorticoid agonists are needed to further investigate HPA axis regulation in PTSD.