For decades, the established science has held that prescription stimulants for ADHD (such as methylphenidate) work by recalibrating the patient’s focus, while boosting cognitive control.
But now a sweeping new neuroimaging study threatens to rewrite that narrative.
In research appearing in the journal Cell, investigators report that stimulants don’t really do much in terms of altering the brain’s canonical attention networks. Instead, the paper’s authors argue that they appear to drive performance by fueling arousal, vigilance, and the perceived value of tasks. In short, the drugs essentially make people more awake, more motivated, and more persistent.
“I prescribe a lot of stimulants as a child neurologist, and I’ve always been taught that they facilitate attention systems to give people more voluntary control over what they pay attention to,” lead author and Washington University assistant professor of neurology Benjamin Kay, MD, PhD, explained. “But we’ve shown that’s not the case. Rather, the improvement we observe in attention is a secondary effect of a child being more alert and finding a task more rewarding, which naturally helps them pay more attention to it.”
Methodology
The study draws on resting-state functional MRI data that the researchers pulled from nearly 12,000 children between 8 and 11 who were enrolled in the Adolescent Brain Cognitive Development (ABCD) Study. The researchers focused on children who took prescription stimulants – most for ADHD – on the day of their brain scan.
To validate those observational findings, the team then replicated the analysis in a tightly controlled “precision imaging” trial involving five healthy adults who underwent hours of brain scanning both on and off methylphenidate.
Across both datasets, the result remained surprisingly consistent. Stimulants changed functional connectivity in brain regions tied to arousal and reward. But the drugs left the brain’s attention networks largely untouched.
Not Attention. Arousal and Reward.
More specifically, stimulant use tweaked the connectivity in sensorimotor and action-related regions of the brain. These same patterns closely resembled the brain connectivity seen after longer sleep. This, the authors noted, suggests that stimulants mimic the neural effects of being better rested.
Stimulants also increased connectivity within salience and parietal memory networks, systems closely tied to dopamine signaling, motivation, and reward-based learning.
The stimulants didn’t influence the dorsal or ventral attention networks, nor the frontoparietal control systems we associate with focus and executive function. The researchers boasted enough statistical power to detect such effects. But they failed to find any.
The data suggest that stimulants enhance performance by increasing vigilance and task value rather than by boosting attentional capacity directly.
One of the study’s most provocative findings involved sleep. In children who were sleep-deprived, stimulant use reversed both the brain-connectivity changes and the academic performance deficits associated with a lack of sleep.
In effect, stimulants temporarily “rescued” the brain from the neural consequences of poor sleep. They stabilized connectivity patterns and improved academic performance. Among well-rested children without ADHD, however, stimulants didn’t do much.
The authors caution that this short-term compensation shouldn’t be mistaken for a sleep substitute. Chronic sleep deprivation carries well-documented long-term risks. Still, the findings could help explain why stimulants seem to be so effective in real-world settings, where sleep loss is far more common.
Rethinking How Stimulants Work
The study also addressed a lingering paradox. Stimulants help tamp down hyperactive behavior while – at the same time – boosting athletic performance and tenacity. The answer, the authors argue, lies not in motor suppression or improved attention, but a simple adjustment to motivation.
By amplifying salience and reward processing, stimulants might reduce task-switching and increase willingness to persist with less-rewarding activities. As a result, it can look like attention has improved, even when the underlying attention networks remain the same.
This framing aligns with decades of behavioral research showing that stimulants most reliably improve reaction time, effort, and persistence. And that high performers often see little benefit, or even experience overconfidence without objective gains.
Implications for ADHD. And Beyond.
For patients with ADHD, the findings offer a note of reassurance. Kids with ADHD who took stimulants showed improved academic and cognitive outcomes without giving them an unfair advantage.
More broadly, the results challenge popular narratives around stimulants as “cognitive enhancers.” The drugs don’t appear to make its users smarter or more attentive. Rather, the meds increase drive, particularly in situations that threaten it.
That distinction matters, the authors argue, for educators, clinicians, policymakers (and of course, patients) navigating the expanding use of stimulants. In short, stimulants might not sharpen attention. But they make the brain more awake, motivated, and willing to keep going.
Further Reading
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