Microglia-immune cells in the brain-have recently been highlighted to understand the pathophysiology of psychiatric disorders such as schizophrenia, depression, and autism. In this review paper, we introduce the microglia hypothesis for psychiatric disorders. In addition, we introduce our novel translational research approach to psychiatric disorders using microglia-like (iMG) cells directly induced from human blood, these iMG cells can be produced from peripheral monocytes within two weeks using two cytokines: granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-34 (IL-34).