GJA1 and major depressive disorder: Depression has been linked to Cx43 deficits through previous research as decreased Cx43 was found in the post-mortem brains of people diagnosed with major depressive disorder and suicide completers56 as well as in animal models of depression such as chronic unpredictable stress in rats where reduced Cx43 protein levels and GJ coupling were found57,58; notably, the cortex and caudate nucleus in particular are the brain regions where Cx43 deficiency has been described56, which is consistent with the present findings.