The study investigates the relationship between gut microbiota and depression, focusing on the impact of gut microbiota on brain function and behavior. The researchers found that depression is associated with reduced gut microbiota richness and diversity. They conducted a fecal microbiota transplantation (FMT) from depressed patients to a microbiota-depleted rat model, which induced depressive-like behaviors in the rats, including anhedonia and anxiety-like behaviors, as well as altered tryptophan metabolism. The results suggest that gut microbiota may play a causal role in the development of depressive symptoms and could be a potential target for the treatment and prevention of depression. The study also highlights the importance of targeting the gut microbiota in novel antidepressant development and depression prevention strategies.The study investigates the relationship between gut microbiota and depression, focusing on the impact of gut microbiota on brain function and behavior. The researchers found that depression is associated with reduced gut microbiota richness and diversity. They conducted a fecal microbiota transplantation (FMT) from depressed patients to a microbiota-depleted rat model, which induced depressive-like behaviors in the rats, including anhedonia and anxiety-like behaviors, as well as altered tryptophan metabolism. The results suggest that gut microbiota may play a causal role in the development of depressive symptoms and could be a potential target for the treatment and prevention of depression. The study also highlights the importance of targeting the gut microbiota in novel antidepressant development and depression prevention strategies.