Bacteria living in people’s guts have been linked with depression in a significant investigation into the controversial connection between microbes and mental health.
Scientists found two varieties of bacteria were consistently present at low levels in people with depression.
After first making the discovery in a group of more than 1,000 Belgian patients, the team then confirmed their findings in a separate group of a similar size.
The researchers also investigated substances produced by microbes in the gut that may have the ability to tamper with brain chemistry.
While the findings will need to be confirmed with further experiments, the team say their work should allow scientists to zoom in on the links between human gut health and mental illness.
“The notion that microbial metabolites can interact with our brain – and thus behaviour and feelings – is intriguing, but gut microbiome-brain communication has mostly been explored in animal models, with human research lagging behind,” said Professor Jeroen Raes, a scientist at KU Leuven who led the study.