Both are heavily regulated in much of the world, the latter prescribed to people who carry a diagnosis of attention-deficit-hyperactivity disorder, or ADHD. Modafinil is sometimes prescribed off-label for the same reason, but its FDA-approved use is to maintain alertness (pro-vigilance) in people with narcolepsy, shift-work disorder, and sleep apnea. (Modafinil is never to be given to children, the FDA warns, lest it cause “increased suicidal thoughts,” “hostile behavior,” and/or “sudden loss of muscle tone.” The listed side effects in adults include depression, anxiety, aggression, and “other mental problems.”)

But where there is the potential for improvement, risks will and are being taken. Taking Ritalin or Provigil for purposes of hyper-performance currently constitutes illegal drug abuse, but President Donald Trump’s vision for the Food and Drug Administration includes making the marketing of drugs for “off-label” uses much easier for pharmaceutical companies. This would put onus on patients and doctors to weigh known risks and benefits against outsized marketing campaigns.

In that light, Lieb and colleagues have been questioning the role of such drugs and their use as neuro-enhancers—and whether adults who already were performing at high levels cognitively could actually go higher. For the current study, the team turned to chess pros, among the highest of high-functioning thinkers. Thirty-nine players came into the lab on sequential days and took a pill that contained a substance of a nature unknown to the them—an aforementioned drug or a placebo. They then squared off in a total of 3,059 games in various mental states against computer programs.

The results both confirmed and called to question some important emerging ideas about cognitive enhancement.

“We primarily thought that it is not possible to enhance high cognitive tasks and were astonished to find such results,” Lieb told readers of World Chess. The authors estimate that the effect was enough to propel a player up the rankings from around 5,000th in the world to closer to 3,500th. I believe when one plays chess competitively, that’s a big deal. Modafinil users saw an 8 to 15 percent increase in victories, and methylphenidate users saw 6 to 13 percent.

The researchers tested caffeine, too, and it had a strong effect—not far below that of the prescription medications. (The caffeine dose was big, though: 400 milligrams, or around four average cups of home-brewed coffee. Or one of Starbucks’ enormous venti cups.)

But how could these drugs actually make a person better at chess?

The novel finding was that the medications didn’t seem to actually make people think more quickly, exactly. Possibly even the opposite. Because while the overall result was that these drugs were associated with more winning, the users also lost more games because they ran out of time. That’s right. Time. Our old nemesis. The emptiness that consumes us all. Time.