Depression Treatment in China: Gut-Bacteria Link Found for GLP-1 Drug Antidepressant Effect

For patients and families exploring depression treatment in China, the search often extends beyond traditional antidepressants—especially when depression coexists with obesity or type 2 diabetes. A new study from Southeast University reveals a surprising biological pathway: a diabetes drug may relieve depression not through the brain directly, but by reshaping gut bacteria. This discovery could open the door to more targeted therapies for metabolic-related depression.

Depression Treatment in China: New Gut-Brain Mechanism Identified for Liraglutide

Researchers at Southeast University School of Medicine have published findings in Cell Host & Microbe that decode how the GLP-1 analog liraglutide—a medication widely used for type 2 diabetes and weight loss—exerts antidepressant effects. The study, led by Professor Yao Honghong’s team, demonstrates that the antidepressant action is independent of the classical GLP-1 receptor and instead relies on a gut microbiota–endocannabinoid signaling axis.

The research addresses a long-standing clinical controversy. While GLP-1 receptor agonists like liraglutide are effective for glycemic control and weight reduction, their impact on mental health has been inconsistent—some reports suggest increased anxiety or suicidal ideation, while others hint at mood benefits. Until now, whether these drugs could directly influence central emotional circuits remained unclear.

How the Study Was Conducted

Using a chronic unpredictable stress (CUS) mouse model, the team observed that subcutaneous liraglutide significantly improved depression-like behaviors. Crucially, this effect persisted even when the GLP-1 receptor was blocked, indicating an alternative mechanism. The drug was found to accumulate primarily in the gut. When gut microbiota were depleted with antibiotics or when germ-free mice were used, the antidepressant benefit disappeared—confirming the essential role of intestinal bacteria.

Key Bacteria and Signaling Molecule Identified

Liraglutide treatment markedly increased the abundance of Lactobacillus delbrueckii in fecal samples. Fecal microbiota transplantation from liraglutide-treated mice replicated the antidepressant effects in recipient animals. Metabolomic analysis pinpointed the endocannabinoid 2-arachidonoylglycerol (2-AG) as the critical signaling molecule. Both liraglutide and the microbiota transplant elevated peripheral 2-AG levels.

The mechanism involves a cross-species collaboration: L. delbrueckii uses its own triacylglycerol lipase (TGL) to convert triglycerides into diacylglycerol (DAG). Host intestinal DAGL enzymes then convert DAG into 2-AG. This endocannabinoid crosses the blood-brain barrier and acts on CB1 receptors in the basolateral amygdala and dorsomedial hypothalamus, suppressing neuronal hyperexcitability in these emotion-regulating brain regions. The team validated this pathway through engineered bacterial colonization experiments.

Clinical Implications for Depression with Metabolic Comorbidities

The findings offer a mechanistic explanation for the mixed psychiatric observations associated with GLP-1 analogs. By identifying Lactobacillus delbrueckii and 2-AG as key mediators linking microbial metabolism to mood regulation, the study proposes a multi-target intervention strategy for patients suffering from depression alongside obesity or type 2 diabetes. This gut-brain signaling pathway may represent a new therapeutic avenue that bypasses direct central nervous system drug targeting.

The first authors are doctoral student Bian Liang and Associate Professor Cai Yang from Southeast University School of Medicine, with Professor Yao Honghong serving as the corresponding author. The research was supported by the National Science and Technology Innovation 2030 Major Project on Brain Science and Brain-Inspired Intelligence, and the National Natural Science Foundation Distinguished Young Scientist Fund.

Source: 东南大学医学院

Reviewed by ToChinaMed. Published: 2026-06-11. This article is based on publicly available medical news and is not a substitute for professional medical advice.

ToChinaMed helps international patients find reliable medical treatment in China.

What This Means for Patients

For international patients considering treatment in China, this development reflects the growing depth of expertise available in Chinese medical centers. Discuss your specific condition with a qualified specialist to understand if these advances apply to your situation.