CLDN5 mRNA was increased in the occipital cortex (P = 0.0505) and cerebellum (*P = 0.0284) in bipolar brains (Fig. 6B, C), while OCLN was significantly increased in the occipital cortex (*P = 0.0397) of depression brains (Fig. 6B). Here, CLDN5 is linked to major depressive disorder.