GLP-1 Drugs Like Ozempic May Sharply Cut Depression and Anxiety

The blockbuster weight-loss drug semaglutide — sold as Ozempic and Wegovy — may do far more than shrink waistlines. A major new study published in The Lancet Psychiatry in March 2026 has found that patients taking GLP-1 receptor agonists experienced dramatically lower rates of depression, anxiety, and substance use disorders, raising the tantalizing prospect that these medications could become tools in psychiatric care.

The Swedish Study

Researchers at Karolinska Institutet in Sweden, the University of Eastern Finland, and Griffith University in Australia analyzed Swedish national health registry data covering more than 95,000 people diagnosed with depression or anxiety who were prescribed various antidiabetic medications between 2009 and 2022. Of these, 22,480 had used GLP-1 drugs.

The results were striking. During periods when patients took semaglutide, the need for psychiatric care dropped by 42 percent compared to periods when they were not using GLP-1 medications. The risk of hospitalization or sick leave due to depression fell by 44 percent, anxiety disorders by 38 percent, and substance use disorders by 47 percent.

Notably, not all GLP-1 drugs performed equally. Liraglutide showed an 18 percent reduction in psychiatric care needs, while older drugs like exenatide and dulaglutide showed no significant benefit — suggesting something specific about semaglutide's pharmacological profile may be driving the mental health improvements.

Corroborating Evidence

The Swedish findings align with earlier data from the STEP clinical trials. A post hoc analysis of four phase 3 trials published in JAMA Internal Medicine in November 2024, covering 3,377 participants, found that semaglutide did not increase the risk of depression or suicidal ideation and was associated with a small but statistically significant reduction in depressive symptoms compared to placebo.

Meanwhile, preclinical research has begun to illuminate the biological mechanisms at play. GLP-1 receptors are expressed throughout brain regions critical for mood regulation, including the prefrontal cortex, amygdala, hippocampus, and the mesolimbic reward system. Activation of these receptors modulates the release of dopamine, serotonin, and glutamate — neurotransmitters central to mood, motivation, and stress response. Animal studies have also shown that GLP-1 signaling promotes the growth of new neurons in the hippocampus and enhances synaptic plasticity.

A Nuanced Picture

Despite the encouraging signals, experts urge caution. The Lancet Psychiatry study was observational, meaning it cannot prove that semaglutide directly caused the mental health improvements. Confounding factors — such as weight loss itself improving mood, or healthier patients being more likely to stay on medication — could play a role.

There are also contradictory findings. A study published in Scientific Reports found an association between GLP-1 receptor agonist use and increased risk of psychiatric disorders in some populations. Individual case reports have documented worsened depression in certain patients on semaglutide, and people with genetic predispositions toward low dopamine function may respond differently.

Importantly, patients with major depression were excluded from the original phase 3 clinical trials of semaglutide, leaving a significant gap in knowledge about how these drugs affect those with severe pre-existing psychiatric conditions.

What Comes Next

Randomized controlled trials specifically designed to test semaglutide's psychiatric effects are now underway, including a trial at the University of Toronto investigating semaglutide for cognitive dysfunction in major depressive disorder. As GLP-1 drugs become the fastest-growing pharmaceutical category globally — with sales projected to exceed $100 billion by 2030 — understanding their full impact on the brain has become one of medicine's most urgent questions.

For the millions already taking these medications, the emerging evidence offers a compelling secondary benefit. But as researchers at the Science Media Centre noted, "controlled clinical trials are needed to confirm the results" before GLP-1 drugs can be considered a psychiatric treatment.