## Prescription Stimulants Don’t Boost Attention Directly, Study Finds
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 thier 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 growth (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 obs# Stimulant Medications for ADHD May Mask Sleep Deprivation, Study Finds
Matt Miller/WashU medicineWashU 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.
“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 certain specific 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.
The researchers’ results point to the need for future studies on the potential long-term effects of stimulants on brain function. The medications could have a restorative effect by activating the brain’s waste clearing system during wakefulness, but they might also cause lasting damage if used to cover up chronic sleep deficits.