MiRNA Differences Related to Treatment Resistant Schizophrenia

Schizophrenia (SZ) is a serious mental disorder that is typically treated with antipsychotic medication. Treatment-resistant schizophrenia (TRS) is the condition where symptoms remain after pharmacological intervention, resulting in long-lasting functional and social impairments. As the identification and treatment of a TRS patient requires previous failed treatments, early mechanisms of detection are needed in order to quicken the access to effective therapy, as well as improve treatment adherence. In this study, we aim to find a microRNA (miRNA) signature for TRS, as well as to shed some light on the molecular pathways potentially involved in this severe condition. To do this, we compared the blood miRNAs of schizophrenia patients that respond to medication and TRS patients, thus obtaining a 16-miRNA TRS profile. Then, we assessed the ability of this signature to separate responders and TRS patients using hierarchical clustering, observing that most of them are grouped correctly (~70% accuracy). We also conducted a network, pathway analysis, and bibliography search to spot molecular pathways potentially altered in TRS. We found that the response to stress seems to be a key factor in TRS and that proteins p53, SIRT1, MDM2, and TRIM28 could be the potential mediators of such responses. Finally, we suggest a molecular pathway potentially regulated by the miRNAs of the TRS profile. Overall design: We recruited schizophrenia patients with a normal antipsychotic response (MR; n = 19), schizophrenia patients with antipsychotic resistance (MNR; n = 21), patients with a first psychotic episode (P; n = 13), and 43 healthy individuals (C; n = 43). Two blood samples were collected per patient, the first one at the hospital arrival (MRA, MNRA, PA) and the second one at the hospital discharge (MRD, MNRD, PD). To find a miRNA signature of the antipsychotic response, we looked for differences in miRNA expression between the MR and MNR groups.