SST and major depressive disorder: Somatostatin has anti-depressant properties [52, 53]; antidepressants alter somatostatin pharmacology within the brain [54, 55], somatostatin mRNA is decreased in the hypothalamic PeV in a rats subjected to chronic mild stress (a model of depression) [56], and repeated electroconvulsive therapy increases somatostatin expression in the hippocampus [57].