Obesity and diabetes are both tied to a higher risk of mental health problems. At the same time, people with psychiatric disorders are more likely to develop metabolic conditions such as obesity and diabetes. Scientists have long been exploring how these conditions overlap and whether treatments for physical health might also influence mental well-being.

To investigate this connection, researchers analyzed data from nearly 100,000 individuals, including more than 20,000 who had used GLP-1 medications. Participants were tracked using Swedish national health registers from 2009 to 2022.

Reduced Depression Anxiety and Psychiatric Care

The findings showed that GLP-1 medications, especially semaglutide, were associated with fewer psychiatric-related hospital visits and reduced sickness absence. During periods when people were taking semaglutide, the need for such care dropped by 42% compared to periods without GLP-1 use. The risk of depression was 44% lower, while anxiety disorders were reduced by 38%.

Lower Risk of Substance Use and Suicidal Behavior

The study also found a notable decrease in substance use disorders among semaglutide users. Hospital care and time off work related to substance use were 47% lower during treatment periods. In addition, GLP-1 receptor agonists were linked to a reduced risk of suicidal behavior.

One of the study’s authors, Professor Mark Taylor from Griffith University, said the findings were not entirely unexpected: “An earlier study examining Swedish registers found the use of GLP-1 medications to be associated with a reduced risk of alcohol use disorder. Alcohol-related problems often have downstream effects on mood and anxiety, so we expected the effect to be positive on these as well.”

Why Might These Drugs Affect the Brain

Even so, the strength of the associations surprised the research team. “Because this is a registry-based study, we cannot determine exactly why or how these medications affect mood symptoms, but the association was quite strong. It is possible that, in addition to factors such as reduced alcohol consumption, weight loss-related improvements in body image, or relief associated with better glycemic control in diabetes, there may also be direct neurobiological mechanisms involved — for example, through changes in the functioning of the brain’s reward system,” said Research Director, Docent Markku Lähteenvuo from the University of Eastern Finland.

Strong Evidence but More Research Needed

The results were published in The Lancet Psychiatry, a leading journal in the field. While earlier studies on GLP-1 medications and mental health have produced mixed findings, many of those studies were smaller. This large registry-based analysis adds stronger evidence, though further research is still needed to fully understand the link.