However, several studies measuring the hypothalamic–pituitary–adrenal axis response to psychological stress in schizophrenic patients have demonstrated a blunted adrenocorticotropic hormone (ACTH) and cortisol response to stress (Brenner et al., 2009; Goldman, Gnerlich, & Hussain, 2007; Jansen et al., 1998) indicating an involvement of the hypothalamic–pituitary–adrenal axis in the pathophysiology of schizophrenia. This evidence concerns the gene POMC and schizophrenia.