A large U.S. study found semaglutide was not linked to any increased neuropsychiatric risk and was associated with reduced cognitive decline, dementia, and nicotine addiction compared to other diabetes drugs.
48% lower dementia riskSemaglutide users had roughly half the risk of dementia compared to sitagliptin users over 12 months (HR 0.52, 95% CI 0.40–0.68)
What the researchers found
Semaglutide was not associated with increased risk of any of 22 neurological or psychiatric outcomes over 12 months compared to three other diabetes medications. Instead, it was associated with significantly reduced risk of cognitive deficit (HR 0.72, 95% CI 0.64–0.80 vs sitagliptin; HR 0.72, 95% CI 0.63–0.81 vs glipizide), dementia (HR 0.52, 95% CI 0.40–0.68 vs sitagliptin), and nicotine misuse (HR 0.72, 95% CI 0.61–0.85 vs glipizide; HR 0.77, 95% CI 0.65–0.90 vs empagliflozin). No differences were observed in negative control outcomes, strengthening confidence in the findings.
Why it matters
Concerns about suicidality and other neuropsychiatric side effects have dogged GLP-1 receptor agonists. This large-scale study not only found no increased neuropsychiatric risk with semaglutide but discovered potential protective effects on cognition and addiction — findings that could expand semaglutide's therapeutic applications if confirmed in clinical trials.
The numbers in context
n=23,386 matched pairs (vs sitagliptin) · n=22,584 (vs empagliflozin) · n=19,206 (vs glipizide) · cognitive deficit HR 0.72 · dementia HR 0.52 · nicotine misuse HR 0.72–0.82 · 22 outcomes assessed · 12-month follow-up
How the study worked
Retrospective cohort study using TriNetX US Collaborative Network electronic health records covering over 100 million patients. Three propensity-score matched cohorts (1:1) compared semaglutide users with type 2 diabetes to users of sitagliptin, empagliflozin, or glipizide prescribed between December 2017 and May 2021. Cox regression assessed 22 neurological and psychiatric outcomes over 12 months. Negative control outcomes were used to detect unmeasured confounding. Multiple-testing correction was applied.
Who was studied
U.S. adults with type 2 diabetes prescribed semaglutide, propensity-matched to users of sitagliptin, empagliflozin, or glipizide
What this study cannot tell us
Retrospective observational design cannot prove causation. The study relied on electronic health records, which may undercount diagnoses not coded in routine care. The exploratory nature meant no pre-registered protocol. The cohort was U.S.-based and may not generalize globally. Some comparisons lost significance after multiple-testing correction.
How to read the evidence
Large propensity-matched retrospective cohort study with multiple comparator drugs and negative control outcomes to check for bias. While observational and exploratory, the sample size, rigorous matching, and consistency across comparisons provide moderately strong evidence. Causation cannot be established.
When this study was published
Published in 2024 using 2017–2021 data, this study is highly current and directly addresses ongoing safety debates about GLP-1 receptor agonists and mental health.
The bigger picture
This study addresses one of the most debated questions in current medicine: are GLP-1 drugs safe for the brain? The finding that semaglutide may actually protect against cognitive decline aligns with emerging preclinical evidence that GLP-1 receptors in the brain play roles in neuroprotection. Clinical trials are now underway testing semaglutide specifically for Alzheimer's disease and addiction disorders.
Questions still open
- Will the ongoing EVOKE clinical trials confirm semaglutide's potential to prevent or slow Alzheimer's disease?
- What is the mechanism by which GLP-1 receptor agonists might reduce nicotine addiction and other substance use disorders?
- Do these neuroprotective associations hold true for other GLP-1 drugs like liraglutide or tirzepatide?
Common questions
Does semaglutide cause depression or suicidal thoughts?
Could semaglutide really prevent dementia?
Read the original research
12-month neurological and psychiatric outcomes of semaglutide use for type 2 diabetes: a propensity-score matched cohort study.
EClinicalMedicine, 74, 102726
Citation
De Giorgi, Riccardo; Koychev, Ivan; Adler, Amanda I; Cowen, Philip J; Harmer, Catherine J; Harrison, Paul J; Taquet, Maxime. (2024). 12-month neurological and psychiatric outcomes of semaglutide use for type 2 diabetes: a propensity-score matched cohort study.. EClinicalMedicine, 74, 102726. https://doi.org/10.1016/j.eclinm.2024.102726