This article is more than 5 years old. Information may no longer be current.

Oropharyngeal microbiome differs between healthy individuals, those with schizophrenia

Individuals with schizophrenia exhibited increased lactic acid levels in throat samples compared with healthy controls, suggesting utility of the oropharyngeal microbiome in distinguishing schizophrenia.

“The role of the human microbiome in schizophrenia remains largely unexplored. The microbiome has been shown to alter brain development and modulate behavior and cognition in animals through gut-brain connections, and research in humans suggests that it may be a modulating factor in many disorders,” Eduardo Castro-Nallar, a PhD student at George Washington University, and colleagues wrote.

Eduardo Castro-Nallar

Researchers conducted a metagenomic analysis of the oropharyngeal microbiome of 16 individuals with schizophrenia and 16 controls.

At the phylum and genus level, Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria were prominent in both individuals with schizophrenia and controls, while Ascomycota was more abundant among individuals with schizophrenia.

Lactic acid was more prominent among individuals with schizophrenia, including Lactobacilli and Bifidobacterium. Eubacterium halii were also found in individuals with schizophrenia.

Microbiomes of individuals with schizophrenia were characterized by an increased amount of metabolic pathways related to metabolite transport systems including siderophores, glutamate and vitamin B12, while healthy controls had an abundance of carbohydrate and lipid pathways and energy metabolism.

“We have shown that it is possible to distinguish schizophrenia patients from controls by profiling the oropharyngeal microbiome based on the diversity and composition of microbes. Additionally, microbiomes from schizophrenics and controls differ in the functions they potentially encode suggesting it may be important to further characterize other body sites such as the intestines. These differences could be exploited for the development of biomarkers and ultimately for therapeutic interventions,” the researchers concluded. – by Amanda Oldt

Disclosure: Castro-Nallar reports no relevant financial disclosures. Please see the full study for a list of all other authors’ relevant financial disclosures.