Do amphetamines boost brainpower when used in obesity treatment?

Amphetamines are a category of drugs that are known for their ability to increase dopamine levels in the brain, particularly in areas related to reward and executive function. Executive function is the brain's ability to plan, make decisions, and control impulses to reach goals.

This increased dopamine activity helps improve cognitive functions, such as attention and decision-making. Therefore, amphetamines are a cornerstone in the treatment of ADHD and related disorders. In the case of ADHD, amphetamines are thought to upregulate a system characterized by genetically mediated low dopaminergic levels.

There are emerging findings suggesting substantial neurobiological overlap between ADHD and eating disorders. A previous review found that participants with obesity performed significantly worse when measuring some executive functions, as compared to healthy non-obese controls.

Further amphetamines have a direct effect on the brain mechanisms behind hunger and eating. Hence, amphetamines have more recently been used in the treatment of binge eating disorders. But - there has been very limited examination of the impact of this treatment on cognition.

So what happens with the executive functions of an obese neurotypical person if you treat their obesity with amphetamine? Studies have already shown that they will lose weight - but is there also a measurable change in their brain function? And thereby a risk of addiction?

The study
The study was conducted to investigate the effects of dextroamphetamine, a form of amphetamine, on executive function in obese individuals. They were otherwise healthy and considered neurotypical.

The participants, 52 adults with a body mass index ranging from 25 to 60, were divided into two groups: one group received the drug, and the other a placebo.

Using a double-blind randomized controlled design, the study aimed to assess changes in executive function and response inhibition over a six-week treatment period.

The participants were given tasks to measure their ability to inhibit impulsive behaviors, such as the Stop-Signal Task, which tracks how quickly participants can stop themselves from responding when prompted.

Patients in the treatment group experienced significant weight loss across the trial.

Contrary to expectations, participants in the treatment group did not report enhanced subjective executive function relative to those in the control group. There was also no evidence of improved response inhibition among those in the treatment versus control group.

Implications for Future Research
These findings highlight the complexity of using amphetamines to treat obesity and related conditions.

Although amphetamines have shown promise in treating some eating disorders, the results of this study suggest that the effects on executive function in obese neurotypicals are less clear.

Additionally, the long-term effects of amphetamines on cognitive function and the risk of developing substance use disorders remain an important area for further investigation.

Thus, while the treatment in this study appeared unlikely to render individuals susceptible to substance use disorders, the parallels with ADHD might be overstated.

About the scientific paper:

First author: Antoinette Poulton, Australia
Published in: Brain Science, December 2024
Link to paper: https://www.mdpi.com/2076-3425/14/12/1274