SLC39A8 and major depressive disorder: The dysfunction of SLC39A8 had an impact on alterations in glutamate and immune function, for example, a reduction in GluN2A and GluA1/2/3 receptor surface expression, decreased BBB integrity, and increased IL-6/IL-1β protein expression (53), which may indicate that the occurrence of DCC and MDD, and LCU and insomnia is medicated by glutamate signaling and altered immune and inflammatory signals (54, 55).