Prescription stimulants such as Ritalin and Adderall have long been thought to treat ADHD by acting upon regions of the brain that control attention. However, a new study by researchers at Washington University School of Medicine in St. Louis casts doubt on that thinking, showing that these drugs act primarily on the brain’s reward and wakefulness centers rather than on its attention circuitry.
The findings, published in Cell, were based on examination of resting-state functional MRI data from 5,795 children ages 8 to 11 who participated in the Adolescent Brain Cognitive Development Study. Compared with kids not taking stimulants, children who took stimulants 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 observation in an experiment on five healthy adults without ADHD. Participants were scanned using resting-state fMRI before and after taking a dose of stimulant medication. Again, arousal and reward centers in the brain, not attention centers, were activated by the medications. “Essentially, we found that stimulants pre-reward our brains and allow us to keep working at things that wouldn’t normally hold our interest,” said Nico U. Dosenbach, MD, PhD, the David M. & Tracy S. Holtzman Professor of Neurology.
Children with ADHD who took stimulant medication had better grades in school and performed better on cognitive tests. However, stimulants did not correspond with improved performance for neurotypical kids who got sufficient sleep. For those who got less than nine hours of sleep, taking a stimulant provided cognitive gains. The study suggests the importance of addressing inadequate sleep in addition to considering stimulant medication for children being evaluated for ADHD.
This article is an AI-assisted summary. All facts and figures are drawn from the original report: https://www.newswise.com/articles/stimulant-adhd-medications-work-differently-than-thought/?sc=rsmn