Prescription stimulants like Ritalin and Adderall are commonly used to treat Attention Deficit Hyperactivity Disorder (ADHD), especially among children. In the United States, approximately 3.5 million children aged 3 to 17 are prescribed these medications. Recent research from the Washington University School of Medicine in St. Louis challenges long-held beliefs about how these drugs function in the brain.
A study led by Dr. Benjamin Kay and Dr. Nico U. Dosenbach found that stimulant medications primarily affect the brain’s reward and wakefulness centers, rather than directly enhancing attention. Their findings, published on December 24, 2025, in the journal Cell, suggest that these medications improve performance by increasing alertness and engagement in tasks, rather than by directly improving focus.
Revisiting ADHD Treatment Strategies
Dr. Kay, a child neurologist at St. Louis Children’s Hospital, noted, “I prescribe a lot of stimulants… But we’ve shown that’s not the case. The improvement we observe in attention is a secondary effect of a child being more alert and finding a task more rewarding.” This insight emphasizes the need for clinicians to consider factors like sleep deprivation when evaluating children for ADHD.
To investigate the impact of stimulant medications on brain function, the research team analyzed resting-state functional MRI (fMRI) data from 5,795 children aged 8 to 11 participating in the Adolescent Brain Cognitive Development (ABCD) Study. The study focuses on tracking the neurodevelopment of over 11,000 children across the U.S. Researchers compared brain connectivity patterns between children taking stimulants and those who were not.
The results demonstrated that children who took stimulant medications exhibited increased brain activity in regions associated with arousal and reward, while the activity in attention-related areas was not significantly elevated. This pattern was further validated through experiments involving five healthy adults who were scanned before and after taking a dose of a stimulant.
Understanding Motivation and Cognitive Performance
Dr. Dosenbach explained that stimulants effectively enhance motivation for tasks that typically do not capture interest, such as less preferred school subjects. “Essentially, we found that stimulants pre-reward our brains and allow us to keep working at things that wouldn’t normally hold our interest,” he said. This newfound understanding suggests that stimulants assist in managing hyperactivity by making previously unappealing tasks feel more rewarding, enabling children to engage with them more effectively.
The research also indicated that children with ADHD who took stimulant medications generally performed better academically and on cognitive tests than those who did not. Notably, children with more severe ADHD symptoms experienced the most significant cognitive improvements. However, stimulant medications did not uniformly enhance cognitive performance across all children.
Interestingly, among participants who received less than the recommended nine hours of sleep per night, stimulant use resulted in better academic performance compared to those who did not take stimulants. This effect was not observed in neurotypical children who had adequate sleep. “If a participant didn’t sleep enough, but they took a stimulant, the brain signature of insufficient sleep was erased,” Dr. Dosenbach noted.
Despite the apparent benefits, both researchers caution about the potential long-term impacts of stimulant use, especially regarding children with sleep deficits. Dr. Kay highlighted the risk of misdiagnosis, where children showing ADHD symptoms due to insufficient sleep may be incorrectly treated with stimulants, masking the real issue.
The findings prompt a call for further studies to explore the long-term effects of stimulant medications on brain health. Researchers suggest that while stimulants may activate the brain’s waste-clearing system during wakefulness, there is also a risk of potential harm if used to compensate for chronic sleep deprivation.
This research underscores the significance of addressing sleep issues alongside consideration of stimulant medications in children diagnosed with ADHD. As the understanding of ADHD treatment evolves, clinicians are encouraged to evaluate each child’s unique circumstances, including their sleep patterns, to optimize care.
