A Better Understanding of GLP-1s: In Conversation With Roger S. McIntyre, MD, FRCPC

BRAIN TRUST: CONVERSATIONS IN PSYCHOPHARMACOLOGY

-Series Editor Joseph F. Goldberg, MD

Joseph F. Goldberg, MD, in this installment of "Brain Trust: Conversations in Psychopharmacology," sits down with Roger S. McIntyre, MD, FRCPC, to discuss glucagon-like peptide-1 (GLP-1) agonists and their role in psychiatry.

McIntyre highlights the transformative impact of GLP-1 agonists on weight and glucose management. GLP-1s are "truly transformative," McIntyre says, as they affect the brain in a way that suggests they are psychiatric drugs. There are currently 5 indications approved by the US Food and Drug Administration for obesity, diabetes, sleep apnea, cardiovascular disease, and kidney disease.¹ While their use in psychiatry is off-label—for example, managing weight gain from antipsychotics—effects on brain plasticity, reward systems, and inflammation, suggest they have a broad range of uses in the space and mental health prescribers should be familiar with these drugs.²

"There is in fact a relationship or association between obesity and type II diabetes, or impaired glucose tolerance, and its effect on the brain," said McIntyre. "When the brain is exposed to the milieu created by obesity or impaired glucose tolerance, that jeopardizes brain health that manifests in different types of neurologic and psychiatric disorders."

Goldberg and McIntyre also discuss the importance of collaboration with specialists for managing complex metabolic conditions, in order "to help the patient as part of the circle of care

"The future is very exciting. I'd encourage colleagues to stay tuned. We have many difficult to treat conditions in psychiatry, not just weight gain from drugs, but also cognitive impairment in schizophrenia, bipolar depression, treating anhedonia, and treating aspects of the medical problems we talked about. GLP-1s have moved into late phase development in the prevention of cognitive impairment in Alzheimer disease, the prevention of episodes in bipolar depression and schizophrenia, and other things like alcohol use disorder, smoking, and the list keeps going. These are well along in terms of development," said McIntyre.

You can read more on GLP-1s and their potential as game-changers in psychiatric treatment from McIntyre in the 2025 July cover story of Psychiatric Times. Read it here.

Dr Goldberg is a clinical professor of psychiatry at The Icahn School of Medicine at Mount Sinai in New York, NY and the immediate-past president of the American Society of Clinical Psychopharmacology.

Dr McIntyre is a professor of psychiatry and pharmacology at the University of

Toronto and head of the Mood Disorders Psychopharmacology Unit at the University Health Network in Toronto, Canada. He is also the executive director of the Brain and Cognition Discovery Foundation and director and cochair of the scientific advisory board of the Depression and Bipolar Support Alliance. He is a professor and Nanshan Scholar at Guangzhou Medical University in China, an adjunct professor at Korea University College of Medicine in Seoul, a clinical professor at the State University of New York Upstate Medical University in Syracuse, and a clinical professor in the Department of Psychiatry and Neurosciences at the University of California Riverside School of Medicine. He is the founder of the Canadian Rapid Treatment Centre of Excellence and CEO of Braxia Scientific Corp.

References

1. FDA approves first generic of once-daily GLP-1 injection to lower blood sugar in patients with type 2 diabetes. FDA. News release. December 23, 2024. Accessed September 15, 2025. https://www.fda.gov/news-events/press-announcements/fda-approves-first-generic-once-daily-glp-1-injection-lower-blood-sugar-patients-type-2-diabetes

2. Gunturu S. The potential role of GLP-1 agonists in psychiatric disorders: a paradigm shift in mental health treatment. Indian J Psychol Med. 2024;46(3):193-195.