SST and depressive disorder: SST+ interneurons in particular are thought to play an important role in the onset of depression, as somatostatin immunoreactivity is decreased in the dorsolateral prefrontal cortex, amygdala, and anterior cingulate cortex post-mortem tissue from depressed patients (while PV+ interneurons appear to be unaffected) (Rajkowska et al., 2007; Tripp et al., 2011; Douillard-Guilloux et al., 2017; Fee et al., 2017; Anderson et al., 2020).