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Stimulant medications like methylphenidate (Ritalin) and lisdexamfetamine (Vyvanse) are dispensed at a rate of 6.1 prescriptions per 100 Americans annually, rising to 24.6 per 100 among boys aged 10-19 years, making them among the most commonly prescribed controlled substances in the country.
These medications work by blocking the reuptake of dopamine and norepinephrine, increasing levels of these neurotransmitters at synapses. The long-time prevailing assumption has been that this mechanism treats attention deficit hyperactivity disorder (ADHD) by activating prefrontal attention circuits.
But what if that assumption has been wrong all along?
A new analysis published in Cell of brain imaging data from nearly 12,000 children shows that stimulants act primarily on arousal and reward systems, changing connectivity in brain regions governing wakefulness and reward anticipation. They have no significant effect on attention networks in the brain.
“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,” study co-author Benjamin Kay, MD, PhD, a pediatric neurologist and assistant professor of neurology at Washington University School of Medicine in St. Louis told Medscape Medical News. “But we’ve shown that’s not the case.”
The findings could change the way researchers and clinicians look at ADHD and suggest stimulants are treating a condition many clinicians aren’t even fully screening for — chronic exhaustion.
The study emerged from paradoxes in the standard explanations for how stimulants work. Stimulants calm hyperactivity in children with ADHD yet tend to make those without ADHD more active.
“Prior explanations couldn’t properly account for that,” Nico U. Dosenbach, MD, PhD, pediatric neurologist and professor of neurology at Washington University School of Medicine, told Medscape Medical News. Dosenbach is senior author of the study.
But interpreting brain scans in ADHD research is notoriously difficult. Children with ADHD move more during scans than neurotypical children, and this head motion creates spurious patterns in connectivity data that have led earlier studies astray.
A separate methodological study by the same team confirmed the stimulant findings weren’t artifacts of motion differences between medicated and unmedicated children.
“Once it was clear that the results weren’t affected by artifacts, the inconsistencies in the previously standard stories about stimulants and ADHD made me very open to the notion that the previous explanations might be incorrect,” added Dosenbach.
The other motivation was the issue of hyperfocus. Stimulants are supposed to correct attention deficits, but kids with ADHD often hyperfocus on things they find fun, interesting, or engaging.
“Do kids with ADHD even have an attention deficit? If they don’t have an attention deficit, then what are the stimulants doing?” Dosenbach said.
For the current study, researchers drew on data from the largest longitudinal study of child brain development and health, the Adolescent Brain Cognitive Development (ABCD) Study.
They examined resting-state functional MRI (fMRI) data from 11,875 children aged 8-11 years, including 337 who took stimulants on the morning of their scans to compare brain connectivity patterns between children on and off medication.
Despite 95% statistical power to detect changes in the dorsal attention network, ventral attention network, and frontoparietal network, the researchers found no significant differences in any of these systems.
“If you rank all the places in the brain where changes occur, the attention areas are ranked last,” said Dosenbach.
The imaging results revealed that the drugs were bypassing the brain’s attention centers entirely, acting instead on sensorimotor and salience networks, which are responsible for keeping individuals awake and helping them decide what is worth doing.
This pattern tracked precisely with norepinephrine transporter maps, suggesting a mechanism of pure arousal. When the team replicated the experiment in a rigorous precision trial of healthy adults, the same patterns emerged.
The conclusion was stark: The drugs were not enhancing the brain’s ability to attend, but rather its willingness to participate.
For Dosenbach, the findings reframe what ADHD is, and why the medical community decided to arrive at that name for a condition that seems to not primarily involve attention.
“ADHD is a terrible name because I think there’s no attention deficit,” he said. “It never made sense to me that you’re supposed to have an attention deficit, but then if you’re doing something you find interesting, you can hyperfocus and ‘lock in’ completely.”
He recalled a father who insisted his son must be faking ADHD because the boy couldn’t sit still during math class but remained motionless for hours in a hunting stand, waiting for prey. “He wasn’t faking it,” Dosenbach said. “The differences in attention can be day and night depending on whether you really want to do something.”
The study suggests we have fundamentally misunderstood the wiggles and fidgets of ADHD. Rather than a motor error, hyperactivity in the brain compels the body to constantly switch tasks in pursuit of a dopamine payoff that never comes. The researchers found that stimulants act on the networks that govern anticipated and perceived reward, effectively elevating the value of mundane work.
By making boring tasks feel meaningful, the drug boosts the brain’s ability to persist.
“Essentially, we found that stimulants prereward our brains and allow us to keep working at things that wouldn’t normally hold our interest,” Dosenbach explained. “It’s a persistence drug to help us keep working on boring things. It gives you nothing if you already like what you’re doing.”
The most startling revelation may be that stimulants are treating a condition many clinicians aren’t even fully screening for — chronic exhaustion.
In the ABCD cohort, less than half of the children (48%) achieved the recommended 9 hours of sleep per night. Remarkably, the functional connectivity pattern produced by stimulants mirrored that of adequate sleep substantially, suggesting the drugs effectively restore what’s lost when children don’t get enough sleep, furthering the evidence that any kind of “attention enhancement” is a minor component of how these drugs work, investigators said.
Stimulants even appeared to restore the cognitive deficits that accompany it. Sleep-deprived children who took stimulants had school grades equivalent to well-rested children who did not take medication.
“Not getting enough sleep is always bad for you, and it’s especially bad for kids,” Kay said.
He noted that overtired children often exhibit symptoms similar to children with ADHD, where they’re fidgety, impulsive, and unfocused. In these cases, the stimulant appears to help by negating the effects of sleep deprivation, restoring school grades, cognitive test scores, and effectively rescuing the child’s performance in the short term.
But this is a deceptive fix; the drugs merely mask chronic exhaustion, leaving the developing brain vulnerable to cellular stress and neuronal damage.
The findings prompted Kay to change his clinical approach.
“I’m more judicious now,” he said. “The guidelines already say you should screen for sleep disturbances. I used to think, ‘yeah, sure, no big deal.’ But now I’m like, ‘wow, those probably really do contribute.’ If someone’s getting 6 hours of sleep, let’s address that first.”
He also described a pattern where 18-year-olds who excelled in school suddenly present with ADHD symptoms after starting night shift work.
“People should not underestimate how much lifestyle can affect cognitive performance,” he said, while emphasizing that careful clinical history-taking is needed to distinguish lifestyle factors from a condition that was always present but masked by circumstances.
Neuroscientist Amy Arnsten, PhD, Albert E. Kent Professor of Neuroscience and professor of psychology at Yale School of Medicine in New Haven, Connecticut, who was not part of the study, offered a more cautious interpretation, noting that the study’s reliance on resting-state fMRI may limit what it can reveal about attention circuits.
“Neurons in dorsolateral prefrontal cortex are not activated during rest and so changes in the neurochemical state due to a drug have little effect on functional connectivity measurements under these conditions,” Arnsten told Medscape Medical News. “In contrast, they can have large effects when the circuits are activated during a task requiring working memory, attention regulation, or impulse control.”
Dosenbach disagreed with Arnsten’s assertion that a drug has little effect under resting conditions. “That’s unlikely to be true given that we found clear and strong effects of stimulants during the resting state, just not in the attention networks,” he said.
Kay added that the brain spends 95% of its metabolic energy at rest, so prefrontal neurons are certainly active. He also noted that in supplemental analyses, the team examined functional connectivity during an attention-demanding n-back task.
They found patterns in children who performed these tasks mirrored those at rest, with no dramatic stimulant-related changes in canonical attention networks.
Task-based fMRI studies have shown stimulants normalize prefrontal and striatal activity in patients with ADHD during cognitive tasks, which the Cell study authors acknowledge in their paper. However, they argued that task-fMRI findings are confounded by drug-induced improvements in task performance.
“The so-called performance confound is an insurmountable problem,” Dosenbach said. “If you give someone with ADHD a stimulant and they do better on the task, you can’t tell if the difference in the brain is due to the drug or the changed performance.”
“The whole point of this field is trying to learn how stimulants improve symptoms,” Arnsten countered. “Thus, we need to see how they alter brain activity when they are improving performance of tasks linked to symptoms.”
She added that the performance confound argument assumes molecular mechanisms have the same effect on circuits at rest as when those circuits are active. “At the cellular level, I know this is not true.”
The disagreement reflects a deeper tension in the field: researchers studying drug mechanisms want to isolate what a medication does to the brain independent of behavior, while researchers studying clinical efficacy want to understand how brain changes accompany symptom improvement even if the two cannot be cleanly separated.
Arnsten also questioned the clinical relevance of resting-state findings. “We are not trying to learn how stimulants help people at rest,” she said. “ADHD patients are fine at watching TV.”
However, Kay countered that the brain’s resting network configuration persists during tasks: “It’s the baseline state from which all tasks are performed.”
Monica Rosenberg, PhD, an associate professor of psychology at The University of Chicago, Chicago, who studies attention and brain connectivity, raised a different concern. The study shows stimulants change arousal and reward connectivity, and separately shows behavioral improvements, but doesn’t directly link those two findings.
“If the claim is that these medications work by enhancing arousal and motivation, do we see physiological effects on arousal, and do those mediate subsequent behavior improvements?” she said. “That would give perhaps stronger support for the claim.”
The findings are “an interesting hypothesis generator” but “not the end of the story,” Rosenberg said.
Despite the scientists’ differing interpretations, there is agreement on one critical point: Stimulants restore patients to normal function rather than conferring superhuman abilities.
“Some people have the misconception that these medications can make people into super-humans, rather than allowing them to be their own better selves,” Arnsten said, a sentiment shared across all camps.
Kay, Dosenbach, and outside experts agree that stimulants work. The clinical efficacy data are robust.
“We’re not saying don’t give these drugs, the clinical data show they work great,” Dosenbach emphasized. “We’re saying the mechanism of action is different than we thought.”
The findings raise questions about how clinicians should think about patients who may benefit from stimulants. If stimulants work primarily by boosting the perceived reward of uninteresting tasks, children who can hyperfocus on activities they enjoy but struggle with tedious schoolwork may be ideal candidates.
Rather than fixing a “broken” brain, stimulants bridge the gap between what children need to do and what their reward systems naturally motivate them to do.
For clinicians, other practice implications involve taking sleep screening more seriously before initiating stimulants and potentially reframing conversations with patients and families around motivation and reward rather than a broken attention system.
“It can’t be helpful to just stigmatize it or make kids feel bad about themselves,” Dosenbach said. “If you understand that it’s really about predicted rewards, then you can start to work with it rather than against it.”
Dosenbach reported being co-founder of Turing Medical and may have received royalties from FIRMM motion-monitoring software licensed to the company. Roseberg, Kay, and Arnsten reported having no relevant disclosures.
What If We’ve Been Wrong About How ADHD Drugs Work?
David Brzostowicki - February 19, 2026Stimulant medications like methylphenidate (Ritalin) and lisdexamfetamine (Vyvanse) are dispensed at a rate of 6.1 prescriptions per 100 Americans annually, rising to 24.6 per 100 among boys aged 10-19 years, making them among the most commonly prescribed controlled substances in the country.
These medications work by blocking the reuptake of dopamine and norepinephrine, increasing levels of these neurotransmitters at synapses. The long-time prevailing assumption has been that this mechanism treats attention deficit hyperactivity disorder (ADHD) by activating prefrontal attention circuits.
But what if that assumption has been wrong all along?
A new analysis published in Cell of brain imaging data from nearly 12,000 children shows that stimulants act primarily on arousal and reward systems, changing connectivity in brain regions governing wakefulness and reward anticipation. They have no significant effect on attention networks in the brain.
“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,” study co-author Benjamin Kay, MD, PhD, a pediatric neurologist and assistant professor of neurology at Washington University School of Medicine in St. Louis told Medscape Medical News. “But we’ve shown that’s not the case.”
The findings could change the way researchers and clinicians look at ADHD and suggest stimulants are treating a condition many clinicians aren’t even fully screening for — chronic exhaustion.
Attention Networks Rank Last
The study emerged from paradoxes in the standard explanations for how stimulants work. Stimulants calm hyperactivity in children with ADHD yet tend to make those without ADHD more active.
“Prior explanations couldn’t properly account for that,” Nico U. Dosenbach, MD, PhD, pediatric neurologist and professor of neurology at Washington University School of Medicine, told Medscape Medical News. Dosenbach is senior author of the study.
But interpreting brain scans in ADHD research is notoriously difficult. Children with ADHD move more during scans than neurotypical children, and this head motion creates spurious patterns in connectivity data that have led earlier studies astray.
A separate methodological study by the same team confirmed the stimulant findings weren’t artifacts of motion differences between medicated and unmedicated children.
“Once it was clear that the results weren’t affected by artifacts, the inconsistencies in the previously standard stories about stimulants and ADHD made me very open to the notion that the previous explanations might be incorrect,” added Dosenbach.
The other motivation was the issue of hyperfocus. Stimulants are supposed to correct attention deficits, but kids with ADHD often hyperfocus on things they find fun, interesting, or engaging.
“Do kids with ADHD even have an attention deficit? If they don’t have an attention deficit, then what are the stimulants doing?” Dosenbach said.
For the current study, researchers drew on data from the largest longitudinal study of child brain development and health, the Adolescent Brain Cognitive Development (ABCD) Study.
They examined resting-state functional MRI (fMRI) data from 11,875 children aged 8-11 years, including 337 who took stimulants on the morning of their scans to compare brain connectivity patterns between children on and off medication.
Despite 95% statistical power to detect changes in the dorsal attention network, ventral attention network, and frontoparietal network, the researchers found no significant differences in any of these systems.
“If you rank all the places in the brain where changes occur, the attention areas are ranked last,” said Dosenbach.
The imaging results revealed that the drugs were bypassing the brain’s attention centers entirely, acting instead on sensorimotor and salience networks, which are responsible for keeping individuals awake and helping them decide what is worth doing.
This pattern tracked precisely with norepinephrine transporter maps, suggesting a mechanism of pure arousal. When the team replicated the experiment in a rigorous precision trial of healthy adults, the same patterns emerged.
The conclusion was stark: The drugs were not enhancing the brain’s ability to attend, but rather its willingness to participate.
‘A Persistence Drug for Boring Things’
For Dosenbach, the findings reframe what ADHD is, and why the medical community decided to arrive at that name for a condition that seems to not primarily involve attention.
“ADHD is a terrible name because I think there’s no attention deficit,” he said. “It never made sense to me that you’re supposed to have an attention deficit, but then if you’re doing something you find interesting, you can hyperfocus and ‘lock in’ completely.”
He recalled a father who insisted his son must be faking ADHD because the boy couldn’t sit still during math class but remained motionless for hours in a hunting stand, waiting for prey. “He wasn’t faking it,” Dosenbach said. “The differences in attention can be day and night depending on whether you really want to do something.”
The study suggests we have fundamentally misunderstood the wiggles and fidgets of ADHD. Rather than a motor error, hyperactivity in the brain compels the body to constantly switch tasks in pursuit of a dopamine payoff that never comes. The researchers found that stimulants act on the networks that govern anticipated and perceived reward, effectively elevating the value of mundane work.
By making boring tasks feel meaningful, the drug boosts the brain’s ability to persist.
“Essentially, we found that stimulants prereward our brains and allow us to keep working at things that wouldn’t normally hold our interest,” Dosenbach explained. “It’s a persistence drug to help us keep working on boring things. It gives you nothing if you already like what you’re doing.”
Erasing the Sleep Deprivation Brain Signature
The most startling revelation may be that stimulants are treating a condition many clinicians aren’t even fully screening for — chronic exhaustion.
In the ABCD cohort, less than half of the children (48%) achieved the recommended 9 hours of sleep per night. Remarkably, the functional connectivity pattern produced by stimulants mirrored that of adequate sleep substantially, suggesting the drugs effectively restore what’s lost when children don’t get enough sleep, furthering the evidence that any kind of “attention enhancement” is a minor component of how these drugs work, investigators said.
Stimulants even appeared to restore the cognitive deficits that accompany it. Sleep-deprived children who took stimulants had school grades equivalent to well-rested children who did not take medication.
“Not getting enough sleep is always bad for you, and it’s especially bad for kids,” Kay said.
He noted that overtired children often exhibit symptoms similar to children with ADHD, where they’re fidgety, impulsive, and unfocused. In these cases, the stimulant appears to help by negating the effects of sleep deprivation, restoring school grades, cognitive test scores, and effectively rescuing the child’s performance in the short term.
But this is a deceptive fix; the drugs merely mask chronic exhaustion, leaving the developing brain vulnerable to cellular stress and neuronal damage.
The findings prompted Kay to change his clinical approach.
“I’m more judicious now,” he said. “The guidelines already say you should screen for sleep disturbances. I used to think, ‘yeah, sure, no big deal.’ But now I’m like, ‘wow, those probably really do contribute.’ If someone’s getting 6 hours of sleep, let’s address that first.”
He also described a pattern where 18-year-olds who excelled in school suddenly present with ADHD symptoms after starting night shift work.
“People should not underestimate how much lifestyle can affect cognitive performance,” he said, while emphasizing that careful clinical history-taking is needed to distinguish lifestyle factors from a condition that was always present but masked by circumstances.
An Alternative Interpretation
Neuroscientist Amy Arnsten, PhD, Albert E. Kent Professor of Neuroscience and professor of psychology at Yale School of Medicine in New Haven, Connecticut, who was not part of the study, offered a more cautious interpretation, noting that the study’s reliance on resting-state fMRI may limit what it can reveal about attention circuits.
“Neurons in dorsolateral prefrontal cortex are not activated during rest and so changes in the neurochemical state due to a drug have little effect on functional connectivity measurements under these conditions,” Arnsten told Medscape Medical News. “In contrast, they can have large effects when the circuits are activated during a task requiring working memory, attention regulation, or impulse control.”
Dosenbach disagreed with Arnsten’s assertion that a drug has little effect under resting conditions. “That’s unlikely to be true given that we found clear and strong effects of stimulants during the resting state, just not in the attention networks,” he said.
Kay added that the brain spends 95% of its metabolic energy at rest, so prefrontal neurons are certainly active. He also noted that in supplemental analyses, the team examined functional connectivity during an attention-demanding n-back task.
They found patterns in children who performed these tasks mirrored those at rest, with no dramatic stimulant-related changes in canonical attention networks.
Task-based fMRI studies have shown stimulants normalize prefrontal and striatal activity in patients with ADHD during cognitive tasks, which the Cell study authors acknowledge in their paper. However, they argued that task-fMRI findings are confounded by drug-induced improvements in task performance.
“The so-called performance confound is an insurmountable problem,” Dosenbach said. “If you give someone with ADHD a stimulant and they do better on the task, you can’t tell if the difference in the brain is due to the drug or the changed performance.”
“The whole point of this field is trying to learn how stimulants improve symptoms,” Arnsten countered. “Thus, we need to see how they alter brain activity when they are improving performance of tasks linked to symptoms.”
She added that the performance confound argument assumes molecular mechanisms have the same effect on circuits at rest as when those circuits are active. “At the cellular level, I know this is not true.”
The disagreement reflects a deeper tension in the field: researchers studying drug mechanisms want to isolate what a medication does to the brain independent of behavior, while researchers studying clinical efficacy want to understand how brain changes accompany symptom improvement even if the two cannot be cleanly separated.
Arnsten also questioned the clinical relevance of resting-state findings. “We are not trying to learn how stimulants help people at rest,” she said. “ADHD patients are fine at watching TV.”
However, Kay countered that the brain’s resting network configuration persists during tasks: “It’s the baseline state from which all tasks are performed.”
Monica Rosenberg, PhD, an associate professor of psychology at The University of Chicago, Chicago, who studies attention and brain connectivity, raised a different concern. The study shows stimulants change arousal and reward connectivity, and separately shows behavioral improvements, but doesn’t directly link those two findings.
“If the claim is that these medications work by enhancing arousal and motivation, do we see physiological effects on arousal, and do those mediate subsequent behavior improvements?” she said. “That would give perhaps stronger support for the claim.”
The findings are “an interesting hypothesis generator” but “not the end of the story,” Rosenberg said.
Despite the scientists’ differing interpretations, there is agreement on one critical point: Stimulants restore patients to normal function rather than conferring superhuman abilities.
“Some people have the misconception that these medications can make people into super-humans, rather than allowing them to be their own better selves,” Arnsten said, a sentiment shared across all camps.
Clinical Takeaways
Kay, Dosenbach, and outside experts agree that stimulants work. The clinical efficacy data are robust.
“We’re not saying don’t give these drugs, the clinical data show they work great,” Dosenbach emphasized. “We’re saying the mechanism of action is different than we thought.”
The findings raise questions about how clinicians should think about patients who may benefit from stimulants. If stimulants work primarily by boosting the perceived reward of uninteresting tasks, children who can hyperfocus on activities they enjoy but struggle with tedious schoolwork may be ideal candidates.
Rather than fixing a “broken” brain, stimulants bridge the gap between what children need to do and what their reward systems naturally motivate them to do.
For clinicians, other practice implications involve taking sleep screening more seriously before initiating stimulants and potentially reframing conversations with patients and families around motivation and reward rather than a broken attention system.
“It can’t be helpful to just stigmatize it or make kids feel bad about themselves,” Dosenbach said. “If you understand that it’s really about predicted rewards, then you can start to work with it rather than against it.”
Dosenbach reported being co-founder of Turing Medical and may have received royalties from FIRMM motion-monitoring software licensed to the company. Roseberg, Kay, and Arnsten reported having no relevant disclosures.
