Alterations in short-chain fatty acid-associated gut microbiota and tight junction integrity in adolescent major depressive disorder https://www.nature.com/articles/s41398-025-03743-3 How gut bacteria could help to diagnose teen depression https://medicalxpress.com/news/2025-12-gut-bacteria-teen-depression.html The microbiome in MDD patients (MDD = Major depressive disorder) exhibited a lower Firmicutes-to-Bacteroidetes ratio. At the genus level, Intestinimonas and Barnesiella were significantly enriched, while Dialister and Collinsella were considerably reduced