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New research suggests that liraglutide, a weight loss drug in the same class as Ozempic, may improve activity in the area of the brain linked with associative learning. FreshSplash/Getty Images
  • Research has found that people with obesity have impaired metabolic sensing associated with decreased insulin sensitivity, which has been shown to affect behavioral choices (also called associative learning).
  • However, the anti-obesity drug liraglutide appeared to restore this ability to natural levels.
  • Experts say this could be due to the drug’s influence on dopamine levels.
  • If this link holds, this could represent yet another advantage of using GLP-1 drugs in obesity treatment.
  • GLP-1 drugs might also have potential uses in treating other medical conditions that involve low dopamine.

A new study published in the journal Nature Metabolism found that people with obesity (defined by the U.S. Centers for Disease Control and Prevention as having a BMI of 30 or greater) had reduced associative learning ability.

However, people who took the medication liraglutide (sold under the brand names Saxenda and Victoza) appeared to return to normal functioning.

Liraglutide belongs to a class of medications called “GLP-1 agonists,” which activate the GLP-1 receptor causing the pancreas to produce more insulin when blood sugar is high. This drug is used to treat type 2 diabetes. It also has applications in obesity treatment due to the fact that it induces a feeling of satiety, causing people to consume less food.

The study authors explained that associative learning occurs when an external stimulus becomes associated by the brain with some sort of consequence — either positive or negative — which then causes a change in our behavior whenever we are exposed to that stimulus again.

The region of the brain that controls associative learning —the dopaminergic midbrain — is plentiful in receptors for insulin so the research team wanted to learn how this learning process works in both people with obesity and those without.

They also wanted to look at how the weight loss drug liraglutide might affect associative learning.

The study involved 24 individuals with reduced insulin sensitivity and 30 with normal insulin sensitivity.

Each evening, the participants received an injection containing either the medication liraglutide or an inactive placebo.

The following morning, each volunteer was asked to perform a task in order to gauge their associative learning ability.

The researchers found that individuals with obesity did not do as well on the task as those who had a normal BMI.

Additionally, activity in the area of the brain linked with associative learning was reduced in subjects with obesity.

However, after taking a single dose of liraglutide, participants with obesity no longer showed any impairment in associative learning ability compared to those without obesity. Nor did they exhibit any difference in brain activity.

According to Dr. Daniel Atkinson, Clinical Lead at Treated, who was not involved in the study, these findings could indicate that treatment with liraglutide is helping to restore this function in the brains of people with obesity.

So, just how might liraglutide be helping with associative learning?

“The part of the brain that regulates our response to outside stimuli is driven partly by a chemical called dopamine,” explained Atkinson, “and it’s theorized that low levels of a gut hormone called GLP-1 can reduce dopamine activity.”

Atkinson further noted that levels of dopamine tend to be lower in people with obesity.

“Liraglutide helps our guts to produce more GLP-1, which could in turn increase dopamine activity,” he said, “so this might be why the study recorded an upswing in associative learning responses.”

Dr. Dina Peralta-Reich, who is the director of New York Weight Wellness Medicine and a double board-certified MD specializing in Obesity Medicine and Pediatrics, said that when it comes to obesity treatment we know that GLP-1 agonists are very effective aids for weight loss.

“However,” she said, “if we uncover their potential to enhance associative learning among individuals struggling with obesity, it presents yet another substantial advantage in managing obesity through GLP-1s.”

Peralta-Reich further noted that this study looked only at liraglutide, which is a short-acting GLP-1 analog.

“[Y]et it is possible that similar effects could emerge when examining long-acting GLP-1s, she said.

Atkinson added that it is also possible that liraglutide could have utility in other medical conditions that involve lower dopamine activity due to metabolic impairment, such as Parkinson’s disease, depression, psychosis, and cardiovascular disease.

“So it’s possible that in the future, treatments that work in a similar way to liraglutide might not just be used for diabetes and weight loss,” he explained.

“But as is often the case,” Atkinson concluded, “more specific research will be needed to determine how effective these treatments would be if used in this way.”

New research has found evidence that obesity is linked with reduced associative learning ability, which affects behavioral choices.

However, the anti-obesity drug liraglutide seems to be capable of restoring this ability to normal, perhaps due to its effects on dopamine levels.

While we already know that GLP-1 agonists like liraglutide, Ozempic, and Wegovy are effective in treating obesity, this study provides evidence for why they are so helpful.

It also may be possible in the future that these drugs will be used in the treatment of other low-dopamine conditions beyond diabetes and obesity.