Stimulant medications like Ritalin and Adderall may improve focus in children with ADHD not by targeting attention networks, but by increasing alertness and making tasks feel more rewarding. A new study from Washington University in St. Louis, published in the journal Cell, used brain imaging to show these drugs activate arousal and reward systems, sometimes even reversing patterns linked to sleep deprivation.
For decades, ADHD stimulants were believed to directly sharpen attention. However, brain scans from 5,795 children in the Adolescent Brain Cognitive Development (ABCD) study revealed that children who took stimulants showed stronger activity in brain regions tied to wakefulness and reward prediction not in classical attention areas. A smaller experiment with adults confirmed the same pattern.
“What we’re seeing is that stimulants pre-reward the brain, helping kids stick with tasks they’d normally avoid,” explained co-author Dr. Nico U. Dosenbach. He noted that this mechanism could also explain how stimulants reduce hyperactivity: by making mundane tasks feel more engaging, children are less likely to fidget or seek other activities.
The study also found that stimulants appeared to erase brain signatures of sleep deprivation and improve school performance in children with ADHD, especially those who were sleep-deprived. However, in well-rested neurotypical children, the drugs did not boost performance.
“I’ve always been taught these drugs help attention systems, but that’s not what we found,” said lead author Dr. Benjamin Kay. “Improvement in attention is a secondary effect of being more alert and finding tasks more rewarding.”
Dr. Dosenbach added, “If a participant didn’t sleep enough but took a stimulant, the brain signature of insufficient sleep was erased, along with the related behavioral declines.”
The researchers warned that while stimulants might mask the effects of poor sleep, chronic sleep loss remains harmful for children’s long-term health. Symptoms of sleep deprivation can mimic ADHD, leading to potential misdiagnosis. They urge clinicians to evaluate sleep habits during ADHD assessments and prioritize sleep improvement alongside medication.
This study shifts the understanding of how ADHD medications work and highlights the importance of considering sleep quality in diagnosis and treatment. Future research will explore the long-term impacts of stimulant use on the brain, especially when used to compensate for sleep deficits.