ADHD Brains Develop Connections More Slowly

The brains of young people with attention deficit hyperactivity disorder (ADHD) develop more slowly than those of young people without ADHD, according to a new study from the University of Michigan Medical School’s Department of Psychiatry. The researchers found differences in the brain architecture between young people with and without ADHD. Young people with ADHD had limited connections between major brain networks. The results could help scientists establish a biological basis for diagnosing ADHD.

The research team based their work on a large set of detailed brain scans that were publically shared for the benefit of the scientific community. They analyzed functional MRI (fMRI) scans from 275 children and teenagers with ADHD and 481 children and teenagers without ADHD. The fMRI images depicted the brains at rest, which allowed the researchers to evaluate how brain networks communicate with each other. Using “connectomic” methods, the researchers mapped the interconnectivity between brain networks.

Young people with ADHD, compared to their peers, lagged in connective development. The researchers analyzed the connectivity between two major networks: the Default Mode Network (DMN), an internally-focused network, and the Task-Positive Network (TPN), an externally-focused network that processes tasks. Young people with ADHD lag in their development of connections between the DMN and the TPN.

“It is particularly noteworthy that the networks we found to have lagging maturation in ADHD are linked to the very behaviors that are the symptoms of ADHD … This study provides a coarse-grained understanding, and now we want to examine this phenomenon in a more fine-grained way that might lead us to a true biological marker, or neuromarker, for ADHD,” stated lead author Chandra Spirada, Ph.D., assistant professor and psychiatrist with the University of Michigan.

This study builds on other research demonstrating that the DMN and the TPN are affected in people with ADHD. This research refines the scientific community’s understand of how those large-scale networks affect the ADHD brain. These findings could help explain why some people “grow out” of ADHD, while others do not.

This research is published in the Proceedings of the National Academy of Sciences.