The Influence of Gut Bacteria on Behavior and Mood

Gut bacteria can mitigate the lifelong skittishness in mice, transfer of gut bacteria from overweight or thin twins to mice affects their weight, and gut bacteria from a depressed person can induce depressive-like symptoms in mice. Gut bacteria produce psychoactive compounds, including neurotransmitters, that enable them to communicate with the brain via the vagus nerve, which carries 80% of its traffic from the gut to the brain.