The CRF receptor family includes two G-protein-coupled receptors, corticotropin releasing factor-receptor 1(CRF-R1) and corticotropin releasing factor-receptor 2(CRF-R2), which in terms of mood regulation, bind mainly to CRF-R1, which enhances anxiety-depression-like behaviours, and to CRF-R2, which inhibits anxiety-depression-like behaviours (Jezova et al., 1999). This evidence concerns the gene CRHR1 and major depressive disorder.