PSYCHIATRY, MEDICINE AND THE BEHAVIOURAL SCIENCES: Edited by Mohan Isaac and Igor FilipcicGut microbiota and microbiome in schizophreniaSamochowiec, Jerzya; Misiak, Błażejb Author Information aDepartment of Psychiatry, Pomeranian Medical University, Szczecin bDepartment of Psychiatry, Division of Consultation Psychiatry and Neuroscience, Wroclaw Medical University, Wroclaw, Poland Correspondence to Błażej Misiak, MD, PhD, Department of Psychiatry, Division of Consultation Psychiatry and Neuroscience, Wroclaw Medical University, 50-367 Wroclaw, Poland. Tel: +48 71 784 16 30; fax: +48 71 784 16 02; e-mail: [email protected] Current Opinion in Psychiatry: September 2021 - Volume 34 - Issue 5 - p 503-507 doi: 10.1097/YCO.0000000000000733 Buy Metrics Abstract Purpose of review Accumulating evidence indicates that there are bidirectional interactions between the gut microbiota and functioning of the central nervous system. Consequently, it has been proposed that gut microbiota alterations might play an important role in the pathophysiology of schizophrenia. Therefore, in this article, we aimed to perform a narrative review of studies addressing gut microbiota alterations in patients with schizophrenia that were published in the years 2019–2020. Recent findings Several studies have shown a number of gut microbiota alterations at various stages of schizophrenia. Some of them can be associated with neurostructural abnormalities, psychopathological symptoms, subclinical inflammation and cardiovascular risk. Experimental studies clearly show that transplantation of gut microbiota from unmedicated patients with schizophrenia to germ-free mice results in a number of behavioural impairments accompanied by altered neurotransmission. However, findings from clinical trials do not support the use of probiotics as add-on treatments in schizophrenia. Summary Gut microbiota alterations are widely observed in patients with schizophrenia and might account for various biological alterations involved in the cause of psychosis. However, longitudinal studies are still needed to conclude regarding causal associations. Well designed clinical trials are needed to investigate safety and efficacy of probiotics and prebiotics in schizophrenia. Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.