Harvard scientists link gut bacteria to depression through hidden inflammation trigger (opens in new tab)

A gut bacterium may be quietly fueling depression through an unexpected chemical twist. Researchers found that when Morganella morganii interacts with a common pollutant, it produces a molecule that triggers inflammation—something strongly linked to depression. This finding helps explain how gut microbes can influence brain health at a molecular level. It also raises the possibility of new treatments that target the immune system rather than just the brain.