Depression, bipolar disorder, and anxiety share a common gut bacteria

Common factors within the gut-associated with depression and bipolar disorder.


Many previous studies have highlighted the role of gut microbiota in the development of mental illness.

A new study suggests that people with mental illnesses like depression, anxiety, bipolar disorder, and psychosis tend to have lower faecalibacterium and coprococcus. The faecalibacterium and coprococcus are two types of bacteria that have an anti-inflammatory effect within the gut.

This review and meta-analysis of 59 case-control studies observed changes in the gut microbiome of people with mental illnesses.

It found a common, overlapping environment in the gut bacteria of people living with mental illnesses. People with these illnesses had higher levels of Eggerthella, a bacterium with proinflammatory effects.

People with such illnesses are more likely to have gut biomes characterized by a lack of anti-inflammatory-producing bacteria and a higher amount of proinflammatory bacteria.

The study highlights the need for greater awareness of gut health should be considered in treating psychiatric disorders.

Viktoriya Nikolova, the study’s first author from King’s IoPPN, said, “While we haven’t managed to establish biomarkers for specific illnesses, we have found that there is a significant overlap between gut health and the prevalence of mental illness, specifically to the predominance of certain proinflammatory bacteria compared to anti-inflammatory bacteria.”

Professor Allan Young, the study’s lead researcher from King’s IoPPN, said, “To our knowledge, this is the first review to assess changes in the gut microbiota to a range of psychiatric disorders and evaluate their potential as biomarkers.”

“Our findings demonstrate that changes in the composition of the microbiota are widespread and, even though it is likely to be a lot more complicated than that, we see some indication of how they may be linked to other known underlying mechanisms of mental illness, such as the regulation of inflammatory processes. It is becoming more and more clear that the health of the gut microbiota is vitally important to the wider mental health of individuals.”

Journal Reference:
  1. Viktoriya L. Nikolova et al. Perturbations in Gut Microbiota Composition in Psychiatric Disorders. DOI: 10.1001/jamapsychiatry.2021.2573
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