Do GLP-1 drugs help reduce weight and sugar levels in severe mental illness?
People with severe mental illness (SMI) like schizophrenia often have higher risks of obesity and diabetes, partly due to antipsychotic medications. GLP-1 receptor agonists (such as liraglutide, semaglutide, and exenatide) are diabetes and weight-loss drugs that may help. A 2025 meta-analysis of 10 trials found that these drugs significantly reduce weight and blood sugar levels in people with SMI, and most people tolerate them well 4. However, the benefits may not last long after stopping the medication 9.
What the research says
A 2025 systematic review and meta-analysis pooled data from 10 randomized controlled trials involving 665 people with schizophrenia, schizoaffective disorder, or bipolar disorder. Compared to placebo or usual care, GLP-1 receptor agonists (GLP-1RAs) led to an average weight loss of 6.17 kg (about 13.6 pounds) and a reduction in HbA1c (a measure of blood sugar control) of 0.31% 4. Dropout rates due to side effects were similar between the GLP-1RA and placebo groups, suggesting the drugs are generally well tolerated 4.
A separate one-year follow-up study specifically looked at liraglutide in people with schizophrenia-spectrum disorders who were taking clozapine or olanzapine (antipsychotics known to cause weight gain). After 16 weeks of treatment, liraglutide led to significant weight loss and improved blood sugar. One year after stopping the drug, some weight loss was maintained (about 3.8 kg more than placebo), but blood sugar levels had returned to baseline 9. This suggests that ongoing treatment may be needed to keep blood sugar benefits.
People with schizophrenia already face higher risks for heart problems and diabetes. A meta-analysis found that schizophrenia patients have higher heart rates and increased QT dispersion (a measure of heart electrical activity) compared to healthy controls, which may raise the risk of sudden cardiac death 2. Additionally, diabetes is linked to worse cognitive function in older adults with schizophrenia 8. Therefore, managing weight and blood sugar with GLP-1 drugs could have broader health benefits, though more research is needed on long-term effects.
What to ask your doctor
- Could a GLP-1 drug like liraglutide or semaglutide be an option for me to manage weight or blood sugar while taking antipsychotics?
- How long would I need to stay on the medication to see lasting benefits, and what happens if I stop?
- Are there any interactions between GLP-1 drugs and my current antipsychotic medication?
- What side effects should I watch for, and how do they compare to other weight loss approaches?
This question is drawn from common patient questions about this topic and answered using cited medical research. We do not provide individualized advice.