A new study may be bad news for people who take so-called ‘smart drugs,’ usually prescribed to treat the symptoms of attention deficit hyperactivity disorder (ADHD), thinking they will increase workplace or academic productivity.
Methylphenidate (Ritalin) and dextroamphetamine (Dexedrine) are regularly prescribed for ADHD, targeting the brain chemicals dopamine and norepinephrine to help with attention and focus. While it’s not FDA-approved as a treatment for ADHD, modafinil, which also increases dopamine in the brain, is sometimes used off-label in the US to treat the symptoms of ADHD in adults. The drug is available on prescription in Australia.
Increasingly, these drugs are being obtained without a prescription and used by people without ADHD to enhance workplace or academic productivity. Thought of as cognitive enhancers or ‘smart drugs’, the effectiveness of these drugs on real-world functioning hasn’t been established. Now, researchers from the University of Melbourne and the University of Cambridge have examined whether they provide any cognitive advantage.
The researchers gave 40 healthy participants aged between 18 and 35 standard adult doses of one of the three drugs or a placebo. Participants were then asked to perform the knapsack optimization problem, a representation of the difficulty of tasks encountered in everyday life, four times, at least one week apart.
In the knapsack problem, people are asked to pack a set of items with given values and weights into a container. The purpose is to select which items to fit into the container without exceeding a weight limit.
The researchers found that, in general, participants who had taken one of the drugs showed small decreases in accuracy and efficiency, and it took them longer and more effort to complete the problem compared to those who were given a placebo.
Those who’d been given a placebo and performed at a higher level on the knapsack problem showed a stronger decrease in performance and productivity when given a drug. Conversely, those on the placebo who had lower performance only occasionally showed slight improvement after taking a drug.
“We found that taking the drugs did not increase a participant’s ability to solve the test correctly, and it decreased the score they obtained compared to when they completed the task without drugs,” said Elizabeth Bowman, lead author of the study. “We also found that participants took longer to complete the task, rather than being more efficient.”
The researchers say the results were a surprise.
“It was expected, because of the increased dopamine the drugs induce, we would see increased motivation, and a concurrent increase in the chemical norepinephrine, would cause an increase in effort, which in turn would lead to higher performance,” said Peter Bossaerts, corresponding author of the study. “Performance did not generally increase, so questions remain about how the drugs are affecting people’s minds and decision-making.”
While the study’s findings were instructive, more research is needed to determine what physiological effects the drugs are having on people without ADHD. But the bottom line would appear to be that they don’t offer a great deal in terms of improving cognitive performance.
“Our research shows drugs that are expected to improve cognitive performance may actually be leading to healthy users working harder while producing a lower quality of work in a longer amount of time,” Bowman said.
The study was published in the journal Science Advances.
Source: University of Melbourne
