Gut microbiome and schizophrenia: insights from two-sample Mendelian randomization

Growing evidence suggests a potential link between the gut microbiome and schizophrenia. However, it is unclear whether the gut microbiome is causally associated with schizophrenia. We performed two-sample bidirectional Mendelian randomization to detect bidirectional causal relationships between gut microbiome and schizophrenia. Summary genome-wide association study (GWAS) datasets of the gut microbiome from the MiBioGen consortium (n = 18,340) and schizophrenia (n = 130,644) were utilized in our study. Then a cohort of sensitive analyses was followed to validate the robustness of MR results. We identified nine taxa that exerted positive causal effects on schizophrenia (OR: 1.08-1.16) and six taxa that conferred negative causal effects on schizophrenia (OR: 0.88-0.94). On the other hand, the reverse MR analysis showed that schizophrenia may increase the abundance of nine taxa (OR: 1.03-1.08) and reduce the abundance of two taxa (OR: 0.94). Our study unveiled mutual causal relationships between gut microbiome and schizophrenia. The findings may provide evidence for the treatment potential of gut microbiomes in schizophrenia.