VGF and Alzheimer disease: VGF levels are consistently decreased in brain tissue and CSF samples of patients with AD (Ruetschi et al., 2005; Zhao et al., 2008; Bartolomucci et al., 2010; Cocco et al., 2010; Asano et al., 2011; Jahn et al., 2011; Wijte et al., 2012; Hendrickson et al., 2015; Holtta et al., 2015; Spellman et al., 2015) and postmortem brain tissue samples from depressed male and female subjects (Jiang et al., 2018, 2019a) as compared with controls.