Chronic liraglutide treatment reversed depression-like behavior and cognitive deficits in obese rats by enhancing BDNF, activating the PI3K/Akt/mTOR pathway, and reducing excessive autophagy and neuroinflammation in the hippocampus.
Depression and cognition reversed28 days of liraglutide treatment improved depressive behavior and cognitive deficits in obese rats while increasing hippocampal BDNF and reducing neuroinflammation
What the researchers found
Chronic liraglutide treatment (300 μg/kg/day subcutaneous for 28 days) in high-fat diet obese rats produced multiple neuropsychiatric improvements:
- Reversed depressive-like behavior in sucrose preference test and forced swimming test
- Improved cognitive deficits in Morris water maze test
- Increased hippocampal BDNF, PI3K, Akt, phospho-Akt, and phospho-mTOR expression
- Downregulated autophagy markers (Beclin-1, LC3)
- Reduced inflammatory markers (TNF-α, IL-6)
- Ameliorated HFD-induced hippocampal neurodegeneration
The benefits were mediated through restoration of PI3K/Akt/mTOR signaling and reduction of excessive autophagy-mediated neurodegeneration.
Why it matters
Depression and cognitive impairment are common but often overlooked complications of obesity. The finding that a GLP-1 drug improves these psychiatric symptoms — through specific brain mechanisms — suggests that GLP-1 drugs may offer mental health benefits beyond weight management. This is particularly relevant as millions of patients report improved mood and cognition on these medications, and clinical trials are exploring GLP-1 drugs for neurodegenerative diseases.
How the study worked
Rats were fed a high-fat diet to induce obesity, then received chronic liraglutide (300 μg/kg/day subcutaneous) for 28 days. Behavioral assessments included the sucrose preference test and forced swimming test (depression), and Morris water maze (cognition). Hippocampal tissue was analyzed for BDNF expression, PI3K/Akt/mTOR pathway markers, autophagy markers (Beclin-1, LC3), inflammatory markers (TNF-α, IL-6), and histopathological changes.
What this study cannot tell us
This was an animal study using a high-fat diet model, and rat brain responses may not fully reflect human neuropsychiatric conditions. The 28-day treatment period is relatively short. The behavioral tests used are standard but cannot fully capture the complexity of human depression and cognition. The study did not assess whether benefits persisted after liraglutide was stopped, and the specific dose may not correspond to human therapeutic levels.
How to read the evidence
This is a preclinical rat study providing mechanistic insights into GLP-1 effects on brain function. While it identifies specific molecular pathways, no human data is presented and the behavioral models are simplified representations of human psychiatric conditions.
When this study was published
Published in 2025, this is very recent research contributing to the rapidly growing evidence base for GLP-1 drugs' effects on brain health and mental function.
The bigger picture
Anecdotal reports and observational data increasingly suggest that GLP-1 drugs improve mood and cognitive function in patients. This study provides molecular mechanisms that could explain these observations, linking GLP-1 receptor activation to hippocampal neuroprotection through autophagy regulation. As clinical trials of GLP-1 drugs in depression and Alzheimer's disease progress, preclinical data like this helps identify the relevant pathways.
Questions still open
- Do human patients taking liraglutide or semaglutide for obesity show measurable improvements in depression and cognitive function?
- Is the antidepressant effect of GLP-1 drugs a direct brain effect or secondary to weight loss and metabolic improvement?
- Could GLP-1 drugs be developed specifically for treating obesity-associated psychiatric disorders?
Common questions
Can GLP-1 drugs help with depression?
How does liraglutide affect the brain?
Read the original research
Liraglutide improves depressive and cognitive deficits in a high-fat diet rat model of obesity: the role of hippocampal autophagy and the PI3K/Akt/mTOR pathway.
Psychopharmacology, 242(12), 2801-2816
Citation
Magdy, Yosra M; Kamar, Sherif A; Habib, Mohamed Z; Rady, Hagar Yousry; Rabei, Mohammed R; Khedr, Sara. (2025). Liraglutide improves depressive and cognitive deficits in a high-fat diet rat model of obesity: the role of hippocampal autophagy and the PI3K/Akt/mTOR pathway.. Psychopharmacology, 242(12), 2801-2816. https://doi.org/10.1007/s00213-025-06834-7