For describing this hypothesis we can refer to the role of hypothalamic pituitary adrenocortical (HPA) system and its modulation by corticotrophin-releasing hormone (CRH); in major depression the function of glucocorticoid receptor is impaired which cause an excessive release of neurohormones like CRH and also corticosteroids; also, in anxiety disorders such as panic attack, CRH and corticosteroids levels are elevated [72]. This evidence concerns the gene CRH and major depressive disorder.