CRHR2 and major depressive disorder: Genes involved in the neuroendocrine cortisol pathway, such as corticotropin‐releasing hormone receptor genes (CRHR1 and CRHR2), adrenocorticotropic hormone receptor or melanocortin receptor genes (MC1R‐MC5R), glucocorticoid receptor genes (GCR), and mineralocorticoid receptor gene (MCR), have been implicated in the comorbidity of diabetes and depression [7, 8, 9].