ADHD Stimulants Work by Boosting Reward and Alertness

Author: Washington University School of Medicine in St. Louis
Published: 24 Dec 2025 - Updated: 15 Sep 2026
Publication Details: Peer-Reviewed | Findings

Table of Contents:
Synopsis - Definition - Overview - FAQs - Insights, Updates - Related Content

Synopsis

This research, published in the peer-reviewed journal Cell, challenges decades of medical understanding about how ADHD stimulants function. Scientists at Washington University examined brain scans from nearly 6,000 children and found that medications like Ritalin and Adderall primarily activate reward and arousal centers rather than attention networks. The findings are significant for patients and families because they suggest stimulants work by making tasks feel more engaging and interesting, which naturally improves focus as a secondary effect. Importantly, the study discovered that stimulants can mask the cognitive effects of sleep deprivation, potentially masking a treatable underlying cause of ADHD symptoms - particularly relevant for children who may be misdiagnosed when sleep deprivation is the actual problem.*

At a Glance

• 1 - The study appeared in the journal Cell on December 24, 2025. It was led by neurologists Benjamin Kay and Nico Dosenbach.
• 2 - Findings were verified in five healthy adults who took a dose before and after resting-state scanning. Their reward and arousal centers activated, not attention regions.
• 3 - Stimulants improved grades and cognitive scores only in children with ADHD or those getting insufficient sleep. Neurotypical kids who slept enough saw no measurable benefit.
• 4 - Data came from 5,795 children ages 8 to 11 in the Adolescent Brain Cognitive Development Study, which tracks more than 11,000 U.S. youth. Researchers compared brain connectivity between kids who did and did not take stimulants on scan day.

Topic Definition

ADHD Stimulant Medication

ADHD stimulant medication refers to prescription drugs such as methylphenidate (Ritalin) and amphetamine formulations (Adderall) that are used to manage attention deficit hyperactivity disorder in children and adults. For decades these medications were understood to sharpen focus by acting directly on the brain's attention networks, but neuroimaging research now indicates that their main effect is on the reward and arousal systems instead. In practical terms, the drugs make otherwise dull or difficult tasks feel more engaging and keep a person more awake and alert, and the improvement in attention follows as a secondary result of that shift. Because they can also mimic the restorative signature of a good night's sleep, they may mask sleep deprivation, which is why clinicians are encouraged to weigh a child's sleep habits alongside any decision about medication.

Overview

Stimulant Medications Affect Arousal and Reward, Not Attention networks

Prescription stimulants, such as Ritalin and Adderall, are widely used to treat attention deficit hyperactivity disorder (ADHD), including in children. In the U.S., about 3.5 million kids ages 3 to 17 take an ADHD medication, a number that has increased as more children have been diagnosed with the neurodevelopmental disorder.

Stimulant medications have long been thought to treat ADHD by acting upon regions of the brain that control attention, but a new study by researchers at Washington University School of Medicine in St. Louis casts doubt on that thinking. Led by Benjamin Kay, MD, PhD, an assistant professor of neurology, and Nico U. Dosenbach, MD, PhD, the David M. & Tracy S. Holtzman Professor of Neurology, it shows for the first time that these drugs act primarily on the brain's reward and wakefulness centers, rather than on its attention circuitry.

The findings, published Dec. 24 in Cell, suggest that prescription stimulants enhance performance by making individuals with ADHD more alert and interested in tasks, rather than directly improving their ability to focus. The researchers also found that stimulant medications produced patterns of brain activity that mimicked the effect of good sleep, negating the effects of sleep deprivation on brain activity.

"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," said Kay, who treats patients at St. Louis Children's Hospital. "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."

Kay said the findings point to the importance of addressing inadequate sleep in addition to considering stimulant medication for children being evaluated for ADHD.

Unexpected brain activity

To understand how stimulant medications affect the brain, the research team examined resting-state functional MRI, or fMRI, data - a type of neuroimaging that indicates a person's brain activity when they are not engaged in any specific task - from 5,795 children ages 8 to 11 who participated in the Adolescent Brain Cognitive Development (ABCD) Study. The ABCD study is a long-term, multisite study that is tracking the neurodevelopment of more than 11,000 children from across the U.S., including a site based at WashU Medicine.

The researchers analyzed fMRI scans and compared brain connectivity patterns between children who took prescription stimulants and children who did not on the day of their scan. Compared with kids not taking stimulants, children who took stimulants the day of the scan showed increased activity in regions of the brain related to arousal or wakefulness and regions predicting how rewarding an activity will be. Their scans did not show significantly increased activity in regions classically associated with attention.

The researchers validated their observation in an experiment on five healthy adults without ADHD who normally did not take stimulant medication. The participants were scanned using resting-state fMRI before and after taking a dose of stimulant medication, allowing for precise measurement of changes in brain connectivity. The researchers again found that arousal and reward centers in the brain, not attention centers, were activated by the medications.

"Essentially, we found that stimulants pre-reward our brains and allow us to keep working at things that wouldn't normally hold our interest - like our least favorite class in school, for example," Dosenbach said.

In other words, the study findings suggest that rather than "lighting up" the attention centers of a child with ADHD, stimulant drugs work by helping make activities that the child normally struggles to focus on feel relatively more rewarding, he noted. That extra motivation helps kids continue challenging activities as well as tedious tasks.

"These results also provide a potential explanation for how stimulants treat hyperactivity, which previously seemed paradoxical," Dosenbach added. "Whatever kids can't focus on - those tasks that make them fidgety - are tasks that they find unrewarding. On a stimulant, they can sit still better because they're not getting up to find something better to do."

Stimulants, ADHD and Sleep

Compared with children with ADHD who did not take a stimulant, children with ADHD who took a stimulant medication had better grades in school (as reported by their parents) and performed better on cognitive tests given as part of the ABCD study. Children with more severe ADHD showed the greatest gains in cognitive outcomes associated with taking prescription stimulants.

Despite their significant effects on brain activity, the researchers found that stimulant medications were not associated with cognitive gains in all children taking them. Children who got less than the recommended nine or more hours of sleep per night and took a stimulant received better grades in school than did kids who got insufficient sleep and did not take a stimulant. However, stimulants did not correspond with improved performance for neurotypical kids who got sufficient sleep. (It is not clear why these kids were taking stimulant medications.) That is, stimulants were linked with improved cognitive performance only for participants with ADHD or those who got insufficient sleep.

"We saw that if a participant didn't sleep enough, but they took a stimulant, the brain signature of insufficient sleep was erased, as were the associated behavioral and cognitive decrements," Dosenbach said.

The authors noted that this boost in performance despite a lack of sleep might carry long-term costs.

"Not getting enough sleep is always bad for you, and it's especially bad for kids," Kay said.

He noted that children who are overtired may exhibit classic symptoms of ADHD, such as difficulty paying attention in class or declining grades, leading to a misdiagnosis in some cases when the real culprit is sleep deprivation. The stimulant medication may then appear to help by mimicking some of the effects of a good night's sleep, while still leaving the child vulnerable to long-term effects of sleep deprivation. Kay urged clinicians to consider sleep deprivation as a factor in ADHD diagnoses and to explore strategies or treatments to boost kids' sleep.

Dosenbach and Kay's results point to the need for future studies on the potential long-term effects of stimulants on brain function. The researchers noted that these medications could have a restorative effect by activating the brain's waste clearing system during wakefulness, but it's equally likely they might cause lasting damage if used to cover up chronic sleep deficits.

Authors

Kay BP, Wheelock MD, Siegel JS, Raut R, Chauvin RJ, Metoki A, Rajesh A, Eck A, Pollaro J, Wang A, Suljic V, Adeyemo B, Baden NJ, Scheidter KM, Monk JS, Whiting FI, Ramirez-Perez N, Krimmel SR, Shinohara RT, Tervo-Clemmens B, Hermosillo RJM, Nelson SM, Hendrickson TJ, Madison T, Moore LA, Miranda-Domínguez O, Randolph A, Feczko E, Roland JL, Nicol GE, Laumann TO, Marek S, Gordon EM, Raichle ME, Barch DM, Fair DA, and Dosenbach NUF. "Stimulant medications affect arousal and reward, not attention networks". Cell. Dec. 24, 2025.

Funding

This work was supported by NIH grants NS140256 (EMG, NUFD), EB029343 (MW), MH121518 (SM), MH129493 (DMB), NS123345 (BPK), NS098482 (BPK), DA041148 (DAF), DA04112 (DAF), MH115357 (DAF), MH096773 (DAF and NUFD), MH122066 (EMG, DAF, and NUFD), MH121276 (EMG, DAF, and NUFD), MH124567 (EMG, DAF, and NUFD), and NS129521 (EMG, DAF, and NUFD); by the National Spasmodic Dysphonia Association (EMG); by Mallinckrodt Institute of Radiology pilot funding (EMG); by the Andrew Mellon Predoctoral Fellowship from the Dietrich School of Arts & Sciences, University of Pittsburgh (BTC); and by the Extreme Science and Engineering Discovery Environment (XSEDE) Bridges at the Pittsburgh Supercomputing Center through allocation TG-IBN200009 (BTC).

Computations were performed using the facilities of the Washington University Research Computing and Informatics Facility (RCIF). The RCIF has received funding from NIH S10 program grants: 1S10OD025200-01A1 and 1S10OD030477-01.

Disclaimer

This article reflects the view of the authors and may not reflect the opinions or views of the NIH or ABCD consortium investigators.

WashU Medicine

WashU Medicine is a global leader in academic medicine, including biomedical research, patient care and educational programs with more than 3,000 faculty. Its National Institutes of Health (NIH) research funding portfolio is the second largest among U.S. medical schools and has grown 83% since 2016. Together with institutional investment, WashU Medicine commits well over $1 billion annually to basic and clinical research innovation and training. Its faculty practice is consistently among the top five in the country, with more than 2,000 faculty physicians practicing at 130 locations. With a storied history in MD/PhD training, WashU Medicine recently dedicated $100 million to scholarships and curriculum renewal for its medical students, and is home to top-notch training programs in every medical subspecialty as well as physical therapy, occupational therapy, and audiology and communications sciences.

Frequently Asked Questions

NOTE: Researched FAQs by Disabled World (DW)

Are ADHD stimulants safe for long term use in children

Current research has not fully mapped the long term effects of stimulants on the developing brain, so clinicians monitor growth, sleep, appetite, and cardiovascular signs during ongoing treatment. Families should review the risks and benefits regularly with a prescribing physician.

How much sleep should a school age child get each night

Most guidelines recommend nine or more hours of sleep per night for school age children. Consistent shortfalls can produce inattention and restlessness that resemble ADHD symptoms.

Can poor sleep be mistaken for ADHD in kids

Yes, an overtired child may struggle to pay attention and show declining grades, which can lead to a misdiagnosis. Evaluating sleep habits before starting medication helps clinicians identify the real cause.

What is the difference between Ritalin and Adderall

Ritalin is based on methylphenidate while Adderall is a mix of amphetamine salts, and the two act on brain chemistry through related but distinct mechanisms. A prescriber selects between them based on how a patient responds and tolerates each option.

Do stimulants help people who do not have ADHD

In this research neurotypical children who already slept enough saw no measurable cognitive benefit from taking a stimulant. Any short term alertness does not translate into lasting performance gains for well rested people without ADHD.

What is resting state fMRI

Resting state functional MRI measures patterns of brain activity while a person is awake but not performing any specific task. It lets researchers study how different brain regions connect and communicate at baseline.

Why do stimulants reduce hyperactivity if they are stimulating

The study suggests that tasks a child cannot focus on feel unrewarding, which drives the urge to move around. By making those tasks feel more rewarding, stimulants help the child stay seated and engaged.

Should sleep problems be treated before starting ADHD medication

Experts in this research urge clinicians to consider sleep deprivation as a factor and to explore strategies that improve sleep first. Addressing the basics may resolve symptoms without masking an underlying and treatable cause.

Insights, Analysis, and Developments

Editorial Note: The implications of this research extend beyond clinical practice into how we approach childhood development more broadly. If stimulants essentially "borrow" the effects of good sleep rather than fixing an attention deficit, the message to families and educators becomes clearer: adequate sleep isn't an afterthought to ADHD management but perhaps the most fundamental intervention. This reframing invites a harder look at modern childhood - the screen time, overscheduling, and cultural normalization of sleep loss - and suggests that some of what we label as attention disorders might be better addressed by addressing the basics first.*

Attribution/Source(s): This peer reviewed publication was selected for publishing by the editors of Disabled World (DW) due to its relevance to the disability community. Originally authored by Washington University School of Medicine in St. Louis and published on 24 Dec 2025, this content may have been edited for style, clarity, or brevity.

* Editorial additions by Ian C. Langtree.