DRD2 and schizophrenia: TRS = treatment-resistant schizophrenia; SCZ = schizophrenia, responsive to treatment; PRL = prolactin; APS = antipsychotics; D2R = Dopamine receptor 2; Glu = glutamate; Glx = glutamate and glutamine concentration; ACC = anterior cingulate cortex; E/I = excitatory/inhibitory; GSH = glutathione; UTRS = ultra-treatment-resistant schizophrenia; PRS = polygenic risk score; CNVs = copy number variants.