Harvard researchers have identified how a gut bacterium called Morganella morganii may contribute to depression. When this microbe interacts with diethanolamine, a common industrial pollutant, it produces an altered molecule that activates the immune system and triggers release of interleukin-6, an inflammatory protein strongly linked to major depressive disorder. This discovery provides a concrete molecular mechanism connecting gut bacteria to brain health, moving beyond correlation to causation. It also opens new possibilities for diagnosing depression using DEA as a biomarker and for developing treatments that target inflammation rather than brain chemistry alone. More research is needed to confirm how many depression cases involve this pathway.
