HDAC5 and major depressive disorder: Lithium has been found to decrease the expression of HDAC1, 3, 4, 5, 7, 8, and 10.370,371 Olanzapine enhanced the ac of histone H3 at the promoter regions of BDNF in the hippocampal area of rats with MDD, while concurrently inhibiting HDAC5.372 Combined treatment with lithium and valproic acid has been shown to induce BDNF expression and exhibit neuroprotective effects in MDD.373,374