It’s become increasingly clear that the gut microbiome can affect human health, including mental health. Which bacterial species influence the development of disease and how they do so, however, is only just starting to be unraveled.

For instance, some studies have found compelling links between one species of gut bacteria, Morganella morganii, and major depressive disorder. But until now, no one could tell whether this bacterium somehow helps drive the disorder, the disorder alters the microbiome, or something else is at play.

Harvard Medical School researchers have now pinpointed a biologic mechanism that strengthens the evidence that M. morganii influences brain health and provides a plausible explanation for how it does so.

Summary: A study analyzing data from over 2 million veterans found that GLP-1 receptor agonists, popular weight-loss drugs like Ozempic and Wegovy, provide significant neurological and behavioral health benefits, including reduced risks of addiction, Alzheimer’s, and dementia. However, they also pose risks for pancreatitis and kidney conditions, emphasizing the need for careful monitoring.

The drugs mimic hormones that curb appetite and aid weight loss but may act on brain regions tied to impulse control and inflammation, explaining their broad effects. Researchers stress that while the benefits are modest, they may be impactful for conditions with limited treatment options, highlighting both their potential and limitations.