How Stimulants Really Work

Neuroscientists find that drugs like Ritalin operate by the brain doing a cost-benefit analysis.

THE COMMON ASSUMPTION has long been that Ritalin, Adderall, and other drugs for the treatment of attention deficit hyperactivity disorder (ADHD) work by helping people focus. It turns out there’s more to it.

A study from researchers at Brown marked the first time scientists examined precisely how stimulants such as Ritalin alter cognitive function. They discovered something new: The drugs actually work by directing the brain to fix its attention on the benefits, rather than the costs, of completing difficult tasks.

Study author Michael Frank, a professor of cognitive, linguistic, and psychological sciences and director of the Carney Institute’s new Center for Computational Brain Science, said the study shows the drugs “increase your cognitive motivation: Your perceived benefits of performing a demanding task are elevated, while the perceived costs are reduced. This effect is separate from any changes in actual ability.”

Brown postdoctoral researcher Andrew Westbrook, the study’s lead author, added, “Our brains have been honed to orient us toward the tasks that will have the greatest payoff and the least cost over time.”

Westbrook and Frank hope their study will help future researchers and medical professionals better understand cognitive mechanisms, allowing them to identify connections between levels of the neurotransmitter dopamine and disorders such as anxiety, depression, and ADHD.

“Our research is focused on disentangling neural and cognitive functions to understand people’s different thought processes and evaluate what’s best for their needs,” Frank said.

The study, published in the journal Science, was done in collaboration with Radboud University in the Netherlands and funded by the National Institutes of Health and the Netherlands Organization for Scientific Research. —Jill Kimball