Some people try to get a mental boost by taking medications designed to treat ADHD or counteract sleep disorders, even though they don’t have these conditions. But that may not be such a smart move, since the drugs worsened the performance of people without these conditions on a complex problem-solving task.
The drugs involved include two stimulants: methylphenidate, often sold under the brand name Ritalin, and dextroamphetamine. Both are often prescribed to improve concentration and attention in people with ADHD. They are thought to work by raising levels of dopamine, a brain chemical, as dopamine signaling systems may be less functioning in people with ADHD.
Another drug, called modafinil, is used to help people with excessive fatigue caused by narcolepsy. Modafinil also increases dopamine signaling.
The use of these drugs by people without these conditions has been increasing in universities and workplaces, when preparing for an exam or when a deadline is approaching. People can buy them as “smart drugs” online or from those who have been legitimately prescribed them. “It’s really rampant among students at American universities,” he says. Peter Bossaerts at Cambridge University.
Previous studies have shown that when people without ADHD take stimulants like these, they perform as well on simple memory and concentration tasks as people taking placebo pills. This suggests that any benefit felt by study participants could come from the placebo effect.
Bossaerts and his colleagues wanted to test the drugs in a way that was closer to solving real-world problems. They used an online test called the backpack problem, in which people have to choose among several items of different weights and values to fill a bag, making the total contents as valuable as possible without violating a weight limit. They can try different combinations before submitting their answer.
The researchers asked 40 people to do various versions of the task after taking one of the three drugs or a placebo tablet. Participants visited the laboratory four times, at weekly intervals, for testing after each drug and placebo.
When taking either drug, people put more effort into the task, in terms of the number of different options they tried before submitting their responses and how much time they spent on the task. But they fared worse, as measured by the total value of the items in the bag, compared to taking a placebo.
People would probably think the drugs are helping them, but they’re not, Bossaerts says. “They spend more time [on the task]they move the items a lot more, so they look busier,” he says.
raquel fargason from the University of Alabama at Birmingham says it makes sense that stimulants might be helpful for people with ADHD, but not for those without the condition. “You can have too much dopamine, there is an optimal dose,” she says. “This study really demonstrates that beautifully.”
esteban pharaoh at SUNY Upstate Medical University in upstate New York says that people who take stimulants may not realize that the drugs reduce their performance because they feel like they are working harder. “The drugs will keep people awake and increase motivation,” she says. “They can mistake motivation for something that works.”
Ritalin’s maker, Novartis, had not responded to requests for comment at the time of publication. All three drugs are manufactured by various companies.
