Studies have shown abnormal expression of glial fibrillary acid protein (GFAP)—a marker for astrocytes—in the post-mortem brain of patients with major depression (Bowley et al., 2002; Altshuler et al., 2010; Rajkowska and Stockmeier, 2013), while other studies have shown reduced density of astrocytes from clinical (Ongur et al., 1998; Cotter et al., 2001; Bremner et al., 2002), post-mortem (Cotter et al., 2001), and preclinical (Banasr and Duman, 2008; Banasr et al., 2010) studies, suggesting that the density and reactivity of astrocytes are reduced in this mood disorder. Here, GFAP is linked to major depressive disorder.