Salivary microbiome profiling reveals a dysbiotic schizophrenia-associated microbiota


Schizophrenia is a debilitating mental disorder and often has a prodromal period, referred to as clinical high risk (CHR) for psychosis, prior to the first episode. The etiology and pathogenesis of schizophrenia remain unclear. Despite the human gut microbiome being associated with schizophrenia, the role of the oral microbiome, which is a vital player in the mouth–body connection, is not well understood. To address this, we performed 16S rRNA gene sequencing to investigate the salivary microbiome in 85 patients with drug-naïve first-episode schizophrenia (FES), 43 individuals at CHR, and 80 healthy controls (HCs). The salivary microbiome of FES patients was characterized by higher α-diversity and lower β-diversity heterogeneity than those of CHR subjects and HCs. Proteobacteria, the predominant phylum, was depleted, while Firmicutes and the Firmicutes/Proteobacteria ratio was enriched, in a stepwise manner from HC to CHR to FES. H2S-producing bacteria exhibited disease-stage-specific enrichment and could be potential diagnostic biomarkers for FES and CHR. Certain salivary microbiota exhibited disease-specific correlation patterns with symptomatic severities, peripheral pro-inflammatory cytokines, thioredoxin, and S100B in FES. Furthermore, the metabolic functions from inferred metagenomes of the salivary microbiome were disrupted in FES, especially amino acid metabolism, carbohydrate metabolism, and xenobiotic degradation. This study has established a link between salivary microbiome alterations and disease initiation and provided the hypothesis of how the oral microbiota could influence schizophrenia.


Interesting stuff.

Does that mean it’s unhealthy to kiss schizos

Nope. Those are not infectious.

Really interesting. Might have something there after another 20 years of study.

This study provides a new interpretative frame for understanding the microbial dysbiosis associated with schizophrenia. We hypothesize that dysbiotic oral microbiota will lead to the disturbance of microbial metabolites, and the abnormal metabolites might reach the brain via possible different routes, such as the olfactory tract and the systemic circulation through the blood–brain barrier, causing a chemical and/or redox imbalance in the brain, and finally promote the initiation of schizophrenia. Therefore, we suggest that alterations in the oral microbiota could be considered as interventional and therapeutic strategies for treating or preventing schizophrenia.