Methods of preparing and using neural cells derived from human induced pluripotent stem cell (hiPSCs), particularly hiPSCs derived from subjects with schizophrenia are provided. The hiPSC-derived neural cells can be used to screen test compounds and to identify schizophrenia marker functions. The hiPSC-derived neural cells can be used to diagnose and/or assess the severity of schizophrenia in a subject. Further, may the hiPSC-derived neural cells from a subject be used as an in vitro system to identify the most effective candidate among existing drugs for that specific subject (i.e. personalized medicine).