It’s no secret that there’s a difference between the behaviors of children with attention deficit hyperactivity disorder and the behaviors of kids without the condition. Compared to neurotypical children, ones with ADHD tend to exhibit increased levels of inattention, hyperactivity or both.
While these observable differences may be obvious, what about differences in a child’s brain? Are there any at all?
For parents asking this question, Dr. Daniel Coury, professor of pediatrics at The Ohio State University and a developmental-behavioral pediatrician at Nationwide Children’s Hospital in Columbus, Ohio, says “the short answer is ‘yes.'” ADHD has sometimes been associated with poor parenting, which he says isn’t the case.
“Neuroimaging work has confirmed that there are neuroanatomic differences,” between a child with ADHD and one without ADHD, he says, noting that the “main difference is in the frontal cortex.” That area of the brain, Coury explains, is involved with attention, organization, abstract thinking and keeping track of things. When the frontal cortex isn’t functioning properly, there’s more of a tendency to fidget, act on impulse and do something before considering the consequences, he says.
[See: 8 Things You Didn’t Know About Counseling.]
Changes in Brain Volume — the Amount of Gray and White Matter
Coury notes that there are physical variations involving the thickness of the cortex as well as in the amounts of white and gray matter throughout the brain. Specifically, “there’s decreased cortical thickness and less gray and white matter.”
White matter, Coury explains, pertains to nerves that have a myelin sheath — “think of that as wiring insulation that doesn’t let information that’s carried from one point to the next leak out.” On the other hand, gray matter isn’t as insulated as myelin and has more connections; this relates to memories and facts which are used every day to help a person function optimally.
In a study published in The Lancet Psychiatry in February, over 3,000 people between the ages of 4 and 63 — some with ADHD and some without — received a brain scan. The findings revealed that those with ADHD had smaller brain volume compared to people without ADHD. Interestingly, the differences tended to be most observed in the brains of children with ADHD and not as much in ADHD adult brains.
The study notes that overall brain volume and five of the regional areas pertaining to regulating emotion, motivation and emotional problems — the caudate nucleus, putamen, nucleus accumbens, amygdala and hippocampus — were smaller in people with ADHD. The researchers are therefore inclined to suggest that ADHD is a brain disorder involving developmental delays in various areas of the brain.
[See: 10 Concerns Parents Have About Their Kids’ Health.]
Not About Poor Parenting
“The results from our study confirm that people with ADHD have differences in their brain structure and therefore suggest that ADHD is a disorder of the brain,” says the study’s lead author, Dr. Martine Hoogman of Radboud University Medical Center in Nijmegen, The Netherlands. “We hope that this will help to reduce stigma that ADHD is ‘just a label’ for difficult children or caused by poor parenting. This is definitely not the case, and we hope that this work will contribute to a better understanding of the disorder.”
E. Mark Mahone, a child neuropsychologist, research scientist and the director of the Department of Neuropsychology at the Kennedy Krieger Institute in Maryland, agrees that there have been changes in the way ADHD is explained, saying that it was previously considered a “disruptive behavioral disorder” but that it’s starting to shift towards phraseology that characterizes it as more of a “persistent neurodevelopmental disorder.”
“More of a Delay Than a Deficit”
Of the delays in brain regions linked to ADHD, Mahone explains that gray matter — primarily the number of neurons in the brain — develops in size and volume during the first few years of life, but “prunes off” during puberty so that white matter — mainly cells that “allow for chemical and electrical connections between regions of the brain” — can “take off.”
Abnormal pruning alters the normal trajectory of these connections, he says, which means the brain can’t function well. Delayed pruning can result in a two- to three-year delay in cognitive and behavioral control, which he says can create challenges for kids in elementary and grade school who must interact with other children who may not have this difference. “It’s more of a delay than a deficit,” Mahone says, noting that this isn’t to say that the brain will catch up to that of a neurotypical one. “Even though the brain may start and end in the same place, when the trajectory is altered, the outcome is probably different” in terms of atypical cognitive and behavioral aspects. ” ADHD is a function of atypical brain structure and atypical chemical development.”
Coury says that ADHD brains also have reduced amounts of dopamine, which, according to the American Psychological Association, is a neurotransmitter associated with reward, desire and motivation. A brain deficient in dopamine is linked to a lowered drive and diminished motor control, notes the APA. “It might be that there’s the right amount of dopamine and the right amount of neurons, but not enough for good control,” Coury explains, adding that problems with transporter chemicals or receptors may be at hand.
[See: Hoarding, ADHD, Narcissism: Inside the Minds of History’s Great Personalities.]
Coury explains that the emergence of technology that allows experts to “now physically see differences” and compare ADHD brains and non-ADHD brains is beneficial because it reinforces knowledge about neuroanatomic differences that were known, but not able to be seen, decades ago. “There are physical and functional differences for people with ADHD,” he says, adding that treatment such as medication and behavioral management may be options for a child with ADHD — as well as adults with the disorder — to explore.
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Are Brains Different for Kids Who Have ADHD? originally appeared on usnews.com
