Summary: A large neuroimaging study reports that children aged 9–10 with attention-deficit/hyperactivity disorder (ADHD) show only small differences in structural brain measurements compared with peers without ADHD.
Source: Duke University
Researchers at Duke University School of Medicine report that MRI scans of children aged 9 to 10 years with ADHD revealed only modest structural brain differences compared to children without the diagnosis.
The study suggests that conventional structural MRI provides limited evidence of clear anatomical markers for ADHD at this age, highlighting a need for more sensitive imaging methods and analytical approaches to better understand the neurobiology of ADHD, which affects an estimated 9 percent of U.S. children.
The findings are published in The Lancet Psychiatry.
“There has long been debate about whether ADHD reflects a distinct biological disorder or is part of the normal range of variation in attention and related behaviors,” said Jonathan Posner, M.D., vice chair for research in Duke’s Department of Psychiatry & Behavioral Sciences and senior author of the study.
“Our results do not settle that debate, but we remain convinced that ADHD has biological underpinnings,” Posner added. “It can be both a biological condition and include substantial variation across individuals.”
The team analyzed baseline data from the Adolescent Brain and Cognitive Development (ABCD) Study, a large U.S. cohort that enrolled 10,736 children. Of these participants, 949 met parent-reported criteria for ADHD. As part of enrollment, all children completed MRI scans along with clinical and behavioral assessments.
Comparing structural brain measures between children with and without ADHD, the investigators examined 79 cortical and subcortical metrics. After adjusting for potential confounders and correcting for multiple comparisons, they identified 11 measures that differed significantly, all indicating slightly smaller values in the group with ADHD. However, the effect sizes were small, with Cohen’s d values ranging roughly from −0.11 to −0.06, suggesting limited clinical or diagnostic utility of these differences.
These results contrast with some earlier, smaller studies that reported larger and more widespread structural differences in children with ADHD. The authors note that differences in sample composition may explain these discrepancies: the ABCD cohort is community-based and representative of the general population, includes older children within the 9–10 range, and contains relatively fewer cases of severe ADHD compared with clinical samples.
“ADHD can be disabling for many children, and effective treatments exist,” Posner emphasized. “The absence of strong structural MRI signatures in this study likely reflects limitations of current structural imaging approaches rather than evidence that ADHD lacks biological foundations.”
About this ADHD research news
Author: Sarah Avery
Source: Duke University
Contact: Sarah Avery – Duke University
Image: The image is in the public domain
Original Research: Closed access.
“Structural brain measures among children with and without ADHD in the Adolescent Brain and Cognitive Development Study cohort: a cross-sectional US population-based study” by Joel Bernanke et al. Lancet Psychiatry
Abstract
Structural brain measures among children with and without ADHD in the Adolescent Brain and Cognitive Development Study cohort: a cross-sectional US population-based study
Background
Previous structural neuroimaging studies have reported a range of cortical and subcortical differences in children with ADHD, but many of these studies used smaller or clinically referred samples and did not consistently control for potential confounders. This study uses the ABCD Study, the largest pediatric brain imaging cohort in the United States, to test whether structural MRI measures differ between children with and without ADHD in a sample representative of the general population.
Methods
This cross-sectional analysis used baseline demographic, clinical, and neuroimaging data from the ABCD Study, which enrolled children aged 9–10 years between Sept 1, 2016, and Aug 31, 2018. ADHD status was determined from parent-reported symptoms. Neuroimaging data passed central quality control and standardized processing by the ABCD team. Researchers applied linear mixed-effects models to estimate Cohen’s d for 79 measures of cortical thickness, cortical surface area, and subcortical volume, and used simulation methods to assess the study’s ability to detect effects under possible diagnostic misclassification.
Findings
The analytic sample included 10,736 children (5,592 boys and 5,139 girls) from diverse racial and ethnic backgrounds, of whom 949 met criteria for ADHD and 9,787 did not. After adjusting for covariates and correcting for multiple testing, 11 of 79 brain measures differed significantly, all reflecting modest reductions among children with ADHD. Effect sizes were small and remained similar when sensitivity analyses used more restrictive comparison groups or alternative diagnostic approaches. Simulations indicated the study had sufficient power to detect effects even with potential diagnostic misclassification.
Interpretation
In this population-representative sample of 9–10-year-old children, structural MRI revealed only modest differences between those with and without ADHD. The findings suggest that future work aiming to discover diagnostic biomarkers for ADHD may need to incorporate alternative MRI modalities (for example, functional or diffusion imaging), advanced statistical methods, or different diagnostic frameworks to better capture relevant neurobiological variation.
Funding
Edwin S Webster Foundation and Duke University, NC, USA.