Bacteria in the throat may be linked to schizophrenia, scientists have found.
A study identified a potential link between certain types of bug living in the oropharynx - the area where the tonsils are situated - and the psychotic illness.
Researcher Eduardo Castro-Naller, from George Washington University (GWU) in the US, said: "The oropharynx of schizophrenics seems to harbour different proportions of oral bacteria than healthy individuals.
"Specifically, our analyses revealed an association between microbes such as lactic-acid bacteria and schizophrenics."
Recent studies have indicated that microbiomes - communities of microbes living within our bodies - can affect the immune system and possibly mental health.
The new research found a significant difference between the microbiomes of healthy individuals and schizophrenia patients.
Co-author Dr Keith Crandall, director of GWU's Computational Biology Institute, said: "Our results suggesting a link between microbiome diversity and schizophrenia require replication and expansion to a broader number of individuals for further validation.
"But the results are quite intriguing and suggest potential applications of biomarkers for diagnosis of schizophrenia and important metabolic pathways associated with the disease."
The findings appear in the journal Peer J.