Both excitatory (Figure 3C) and inhibitory neurons (Figure 3D) in PD exhibited similar patterns of higher average expression levels of the NAV3, DLGAP2, KAZN, MTRNR2L12, CCNH and XIST genes compared to MDD excitatory and inhibitory neurons, which both display higher average expression of the MEG3, LRP4, LINGO1 and PDE5A genes. Here, PDE5A is linked to major depressive disorder.