Sex-Based Brain Differences in Kids With ADHD

Boys and girls with ADHD show differences in brain structure that are consistent with differences in presentation of symptoms. Photo © kali9

Research shows the influence of gender on the brain structure of children with ADHD and explores how sex-based differences may affect learning.

Attention deficit hyperactivity disorder (ADHD) is among the most common childhood disorders. It is estimated that nearly 9% of children in the United States have ADHD. Historically, boys are more frequently diagnosed with ADHD, however, the rate of diagnosis among girls is rapidly increasing.

Research examining gender differences in boys and girls with ADHD in comparison to each other and to same sex peers is also growing.

Boys and girls with ADHD often differ in their presentation of symptoms - with boys commonly displaying more of the overt hyperactive/impulsive symptoms and girls more of the subtle inattentive symptoms. In addition, research has found that boys and girls with ADHD also show differences in brain structure and function and that these differences are consistent with differing symptom presentations.

The Study

Researchers at the Kennedy Krieger Institute in Baltimore, Maryland, used advanced brain imaging to take an in-depth look at gender differences in the neuroanatomy of children with ADHD. Specifically, they examined differences in frontal lobe structure and function in 8 – 12-year-old boys and girls with ADHD in comparison to same-sex typically developing peers.

Key Findings

In line with previous research, investigators found that both boys and girls with ADHD showed reductions in cortical surface area compared to peers without ADHD. Boys with ADHD showed posterior premotor cortex (an area associated with motor control) decreases in surface area, while girls with ADHD showed more anterior prefrontal cortex (an area associated with organizational skills) decreases in surface area.

Additionally, researchers found that a decrease in surface area was associated with greater symptom severity.

Discussion of Findings

These anatomical differences appear to be relevant to functional differences between boys and girls with ADHD with findings suggesting that boys in this age group show more impairment in brain areas responsible for motor function and inhibition, while girls show more deficits in circuits responsible for a higher level of organization and planning - findings that mirror differing symptom presentation often seen in boys with ADHD compared to girls with ADHD.

Results may also be reflective of the different neurodevelopmental trajectories typically seen in boys and girls and in children with ADHD compared to those without. "We know it's well established that girls mature earlier than boys, and that pattern also includes early maturation of brain structure and associated functions," said Stewart Mostofsky, MD, Director of the Center for Neurodevelopmental and Imaging Research at Kennedy Krieger Institute and co-author of the study.

"It's also known that motor function matures earlier than prefrontal structure, so given that, it could be possible that if we had looked, for instance, at the girls earlier, we may have seen similar motor problems that the boys showed later," he added.

Future research is needed to clarify whether boys and girls with ADHD follow the same developmental trajectory in surface area, but with girls somewhat ahead of boys, or if these differences in brain characteristics persist despite developmental stage.

“A greater understanding of sex differences in ADHD and trajectories of brain development and functional outcomes has important implications for possible remediation or therapies tailored differentially to boys and girls with ADHD,” note study authors.

The study, Distinct frontal lobe morphology in girls and boys with ADHD, is published in the January issue of NeuroImage: Clinical.


Benjamin Dirlikov, Keri Shiels Rosch, Deana Crocetti,  Martha B. Denckla, E. Mark Mahone, Stewart H. Mostofsky. “Distinct frontal lobe morphology in girls and boys with ADHD” - NeuroImage: Clinical. Volume 7, 2015, Pages 222–229.

Froehlich TE, Lanphear BP, Epstein JN, Barbaresi WJ, Katusic SK, Kahn RS. “Prevalence and Treatment of ADHD in a National Sample of U.S. Children” -  Archives of Pediatrics and Adolescent Medicine. 2007;161(9):  857-864.

Nancy A. Melville. “Sex-Based Brain Differences Visible in Kids With ADHD” - Medscape. Jan 08, 2015.

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