New research finds the drugs can also mask the effects of sleep deprivation, prompting calls for clinicians to consider sleep health in ADHD evaluations.
Key takeaways:
- A study finds ADHD stimulants primarily activate brain regions for arousal and reward, not attention circuits as traditionally believed.
- The medications produce brain activity patterns that mimic the effects of sufficient sleep, negating the cognitive effects of sleep deprivation.
- The findings suggest improved focus is a secondary effect of increased alertness and motivation.
- Researchers urge clinicians to evaluate for sleep deprivation in children with ADHD-like symptoms, as stimulants may mask an underlying sleep issue.
Stimulant medications for attention deficit hyperactivity disorder (ADHD) act on the brain’s reward and wakefulness centers rather than its attention circuitry, according to a new study from Washington University School of Medicine in St Louis. The findings, published in Cell, also show the drugs can produce brain activity patterns that mimic good sleep, potentially masking the effects of sleep deprivation in some children.
The research suggests that stimulants improve performance by making individuals more alert and interested in tasks, not by directly enhancing their ability to focus.
“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,” says Benjamin Kay, MD, PhD, an assistant professor of neurology at Washington University School of Medicine, in a release. “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.”
To understand the medications’ effects, the research team analyzed resting-state functional MRI (fMRI) data from 5,795 children aged 8 to 11 from the Adolescent Brain Cognitive Development (ABCD) Study. They compared brain connectivity between children who took stimulants on the day of their scan and those who did not. Children taking stimulants showed increased activity in brain regions related to arousal and reward, with no significant increase in activity in classic attention networks. These results were validated in a separate experiment with five healthy adults.
A key finding for sleep medicine professionals is the drugs’ interaction with sleep status. Stimulants were linked to improved cognitive performance only for participants with ADHD or those who were sleep-deprived. In children who got less than the recommended nine hours of sleep, taking a stimulant was associated with better grades compared to sleep-deprived children not taking a stimulant.
“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,” says co-author Nico U. Dosenbach, MD, PhD, the David M & Tracy S. Holtzman professor of neurology, in a release.
The authors warn this effect could lead to misdiagnosis and potential long-term harm. Children who are overtired can exhibit symptoms that mimic ADHD, such as inattention and poor academic performance. 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 the 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.
“Not getting enough sleep is always bad for you, and it’s especially bad for kids,” says Kay. He urges clinicians to explore treatments to improve children’s sleep. The researchers noted the need for future studies on the long-term effects of using stimulants to cover chronic sleep deficits.
Photo: WashU Medicine pediatric neurologist Benjamin Kay, MD, PhD, treats children with ADHD. A new study by Kay and colleagues found that stimulant medications commonly prescribed for the condition might mask sleep deprivation by mimicking the effect of good sleep. Credit: Matt Miller/WashU Medicine
