December 11, 2023

A new study may have bad news for those who take so-called “smart drugs,” which are often prescribed to treat symptoms of attention deficit hyperactivity disorder (ADHD), in the belief that they will increase productivity at work or school.

Methylphenidate (Ritalin) and dextroamphetamine (dextroamphetamine), commonly used to treat ADHD, target the brain chemicals dopamine and norepinephrine to help focus and focus. Although not FDA-approved for the treatment of ADHD, modafinil also increases dopamine in the brain and is sometimes used off-label in the United States to treat symptoms of ADHD in adults. This medicine is available by prescription in Australia.

These drugs are increasingly available without a prescription and used by people without ADHD to enhance work or academic productivity. Considered cognitive enhancers or “smart drugs,” the effectiveness of these drugs on real-world function has not been established. Now, researchers at the Universities of Melbourne and Cambridge have investigated whether they offer any cognitive advantages.

The researchers gave 40 healthy participants, aged 18 to 35, either standard adult doses of one of the three drugs or a placebo. Participants were then asked to perform the knapsack optimization problem, a proxy for task difficulty encountered in everyday life, four times, at least one week apart.

In the knapsack problem, one is asked to pack a set of items of given value and weight into a container. The goal is to choose which items to pack into the container without exceeding the weight limit.

The researchers found that, in general, participants who took one of the drugs experienced a slight decrease in accuracy and efficiency, taking longer and more effort to complete the questions than those who took the placebo.

Those who took a placebo and performed better on the knapsack problem showed worse performance and productivity declines when they were given the drug. In contrast, those who performed worse on the placebo showed only occasional slight improvements after taking the drug.

“We found that taking the drug did not improve participants’ ability to solve the test correctly, and it lowered the scores they received compared to when they did the task without the drug,” said Elizabeth Bowman, lead author of the study . “We also found that participants took longer to complete tasks, not more efficiently.”

The researchers said the results were surprising.

“We expected that we would see increased motivation due to the drug-induced increase in dopamine, while an increase in the chemical norepinephrine would lead to increased effort, which in turn would lead to higher performance,” said Peter Bossaerts. Corresponding Author. “Performance didn’t generally improve, so questions remain about how the drug affects people’s thinking and decision-making.”

While the results of this study are suggestive, more research is needed to determine what physiological effects these drugs have on people without ADHD. But most importantly, they don’t offer much in terms of improving cognition.

“Our study suggests that drugs that promise to improve cognitive performance may actually cause healthy users to work harder for a longer period of time while producing lower-quality work,” Bowman said.

The study was published in the journal scientific progress.

source: University of Melbourne