However, it is still unknown which presumptive glial changes are causal for depression, although some post mortem data from patients indicated alterations in astrocytes: GFAP immunoreactivity in cell bodies and fibers was significantly reduced in hippocampal regions CA1 and CA2 of patients with major depression (MD), as well as in patients treated chronically with synthetic glucocorticoids (Muller et al. 2001). This evidence concerns the gene GFAP and major depressive disorder.