Schizophrenia and antipsychotic medications present distinct and shared gut microbial composition: A meta-analysis

There are some conflicting results regarding alterations of gut microbial composition in schizophrenia (SZ), even a few meta-analysis studies have addressed this field. Ignoring of antipsychotic medication effects may cause the large heterogeneity and impact on study results. This study is a meta-analysis to systematically evaluate composition of gut microbiota in patients with SZ, to elucidate the impact of antipsychotic use and reveal distinct and shared gut bacteria in SZ and antipsychotic medications. We re-analyzed the publicly available 16S rRNA-gene amplicon datasets by a standardized pipeline in QIIME2, used the natural log of response ratios as an effect index to directly and quantitatively compare composition of gut microbiota by random-effects meta-analysis with resampling tests in Metawin, ultimately to evaluate distinct abundance of gut bacteria. A total of 19 studies with 1968 participants (1067 patients with SZ and 901 healthy controls (HCs)) were included in this meta-analysis. The alterations of alpha diversity indices occurred in SZ on antipsychotics but not in drug-naïve or -free patients, while variation of beta diversity metrics appeared in SZ regardless of antipsychotic use. After antipsychotic treatment, reversed Simpson index, decreased observed species index and significant difference of Bray-Curtis distance were observed in patients. Especially, risperidone treatment increased the Shannon and Simpson indices. Noteworthy, three differed genera, including Lactobacillus, Roseburia and Dialister, were identified in both states of antipsychotic use. This meta-analysis is to provide a novel insight that SZ and antipsychotic medications present distinct and shared gut microbial composition.