CD4 and schizophrenia: For instance, the increased DRD2mRNA expression levels have also been found by Zvara et al. in PBMCs of drug-naïve or drug-free schizophrenia patients with a varied duration of illness and severe symptoms [39], by Brito-Melo et al. in T cell subsets (CD4 and CD8) of medicated chronic schizophrenia patients with duration of illness >10 years [40], and by Kordi-Tamandani et al. in whole blood samples of schizophrenia patients, not mentioned the medical treatment [41].