LEP and mood disorder: Of the genes commonly regulated by both medications, we focused on the leptin receptor gene (Lepr), as leptin signaling has been implicated in several studies of mood disorders and in the role of neurogenesis in these disorders.27, 28, 29, 30, 31 We asked whether upregulation of Lepr by chronic treatment with Li and VPA involved DNAm changes in the promoter and potential regulatory regions.