Schizophrenia (SZ) is a heterogeneous neuropsychiatric disorder whose complexity has hampered the identification of biomarkers that are actually useful in the clinical practice. Our study is based on the hypothesis that first-episode psychosis (FEP) patients present altered gene expression in blood that correlates with changes in neurons. We have analyzed the expression of genes (associated with SZ in genomic studies) through real-time PCR in peripheral blood from 63 FEP patients and 83 controls. We observed that TOX gene was significantly altered in male patients when compared to male controls, while SP4 expression was altered in both men and women. Conversely, EIF2D, NRGN, SP4 and TRIO were significantly altered when comparing female controls and patients. In addition, seven genes were altered when comparing male patients at baseline and follow-up visits, suggesting effects of medication or disease progression. Recently, we also started a collection of neuronal cells from our FEP cohort. Considering the necessity to develop cellular models that are closer to the disorder compared to blood, olfactory neuroepithelium (ON) cells are an extremely useful surrogate of the SZ brain, considering the noninvasive isolation and the simplicity of their culture, in a patient-specific background. We are currently testing the effects of antipsychotics in gene expression in control- and patient-derived ON cultures. Overall, we found evidence for alterations of multiple genes in the blood of FEP patients, which were heavily dependent upon the patient’s sex. This information could serve as guide for future investigations aiming for the development of new therapeutic approaches.