SST and major depressive disorder: Reduced SST gene expression, mRNA, or protein levels were found in the CSF, SgACC, dlPFC, and amygdala of MDD subjects, and in the medial PFC (mPFC) and hippocampus of animals exposed to CUS (Rubinow et al., 1985; Rajkowska et al., 2007; Sibille et al., 2011; Tripp et al., 2011; Guilloux et al., 2012; Banasr et al., 2017).