This article is more than 5 years old. Information may no longer be current.

Study suggests ADHD causes delay, degeneration of brain volume

Results from an international cross-sectional mega-analysis indicated differences in subcortical brain volume between individuals with ADHD and those without, as well as between children and adults with ADHD.

“Identification of structural brain differences in people with ADHD is important to further insights into the neural substrates of ADHD. So far, analyses of brain structures in ADHD have been small in size and statistical power,” Martine Hoogman, PhD, of Radboud University Medical Center, Nijmegen, Netherlands, and colleagues wrote.

To assess structural differences in children and adults with ADHD compared with those without the disorder, researchers analyzed data from the international ENIGMA Working Group collaboration for 1,713 participants with ADHD and 1,529 controls. Study participants had a median age of 14 years.

Volume of the accumbens, amygdala, caudate, hippocampus, putamen and intracranial volume were smaller among participants with ADHD.

Volume in the pallidum and thalamus did not differ between participants with ADHD and controls.

Exploratory lifespan modelling indicated delayed maturation and degeneration, as effect sizes were highest in children compared with adults in the accumbens, amygdala, caudate, hippocampus, putamen and intracranial volume.

Volume in the pallidum and thalamus did not differ between children and adults with ADHD.

Psychostimulant use, symptom scores, and comorbid psychiatric disorders did not alter these associations.

“This study represents an important contribution to the field by providing robust evidence to support the notion of ADHD as a brain disorder with substantial effects on the volumes of subcortical nuclei,” Claudia Lugo-Candelas, PhD, and Jonathan Posner, MD, of New York State Psychiatric Institute, wrote in an accompanying editorial. “Future meta-analyses and mega-analyses will need to investigate medication effects as well as the developmental course of volumetric differences in this disorder.” – by Amanda Oldt

Disclosure: Hoogman reports no relevant financial disclosures. Posner reports receiving research support from Shire Pharmaceuticals and Aevi Genonic Medicine. Please see the study for a full list of relevant financial disclosures.