HDAC2 and major depressive disorder: Experiments revealed that HDAC2 and HDAC5 expression was significantly increased in MDD patients in the depressive state compared to controls subjects (HDAC2 p < 0.001; HDAC5 p = 0.001), while during remissive state, expression of the same HDACs was comparable to controls subjects (HDAC2 p = 0.975; HDAC5 p = 0.506), suggesting a state-dependent alteration (Figure 2) [78].