GFAP and major depressive disorder: The possible involvement of astrocyte processes at NRs in WM functional and structural changes is consistent with reduced GFAP immunoreactive area fraction of processes and levels that we found in relatively young MDD subjects [53,90] Since repeated stress is a risk factor for MDD [91] structural and molecular alterations associated with astrocyte processes at NRs may occur in prefrontal brain regions of MDD patients.