Study: Ritalin improves numeric memory but not overall cognition in non-ADHD adults

A new study published in Human Psychopharmacology: Clinical and Experimental has found that a low dose of the commonly prescribed ADHD medication methylphenidate may improve accuracy in certain memory tasks but does not enhance overall cognitive function in healthy adults.

Stimulant medications like methylphenidate (sold under brand names such as Ritalin) are widely used to treat attention-deficit/hyperactivity disorder (ADHD). The drug works by increasing levels of dopamine and noradrenaline—neurotransmitters that play key roles in focus, attention, and impulse control.

However, in recent years, many individuals without ADHD—particularly students—have begun using these medications in hopes of boosting concentration and academic performance.

The growing popularity of these so-called “smart drugs” has raised important questions about whether stimulant medications genuinely enhance cognitive abilities in healthy individuals. While earlier research has shown that such drugs may improve working memory and processing speed, much of that work has focused on higher doses or clinical populations.

The current study aimed to explore whether a lower dose (10 mg) of methylphenidate could provide cognitive benefits while minimizing potential side effects.

Led by Amie C. Hayley, researchers at Swinburne University of Technology in Australia conducted a randomized, placebo-controlled crossover study involving 25 healthy adults (36% female, aged 21 to 45 years). Each participant received either a 10 mg dose of methylphenidate or a placebo in two separate sessions, spaced one week apart.

Participants then completed a series of cognitive tasks designed to assess reaction time, working memory, and visual attention. The study also incorporated eye-tracking technology to evaluate whether the drug affected visual scanning behavior.

The results were mixed. Participants performed better on a numeric working memory task after taking methylphenidate, making fewer errors and demonstrating improved accuracy compared to when they received the placebo.

However, the drug did not improve other aspects of cognitive performance, including reaction time, general working memory, or visual scanning efficiency.

“Consistent with prior research, we observed select, modest improvements in tasks that assess numeric working memory. Considering the absence of improvement across other cognitive domains, these findings suggest that the effects produced by low-dose methylphenidate are more dose-limited and task-specific,” Hayley and colleagues concluded.

One limitation of the study is its small sample size. With only 25 participants, it is possible that subtle cognitive effects of methylphenidate went undetected. Additionally, the sample was relatively homogeneous—most participants were young, healthy adults with a high level of education—which may have influenced their baseline performance and sensitivity to the drug.

Despite these limitations, the study contributes to a growing body of research suggesting that the cognitive benefits of stimulant medications may be overstated, particularly for individuals without ADHD.

The study, “Acute Administration of 10 mg Methylphenidate on Cognitive Performance and Visual Scanning in Healthy Adults: Randomised, Double-Blind, Placebo-Controlled Study,” was authored by Blair Aitken, Luke A. Downey, Serah Rose, Brooke Manning, Thomas R. Arkell, Brook Shiferaw, and Amie C. Hayley.