Study Reveals Unique Gene Activity in ADHD Brains
What causes ADHD? New NIH research of ADHD brains shows a unique expression of the genes used to code for neurotransmitters, which power important neural functions like attention and learning, suggesting genetic underpinnings for symptoms.
November 18, 2022
ADHD brains exhibit unique differences in the expression of genes used to code neurotransmitters, the chemical messengers that power attention and communication, among other brain functions. This is the finding of a new study conducted by researchers at the National Institute of Health (NIH) that uncovered a key difference in gene activity in the brains of individuals diagnosed with attention deficit hyperactivity disorder (ADHD).1
The study, led by scientists at the NIH’s National Human Genome Research Institute (NHGRI) and published in Molecular Psychiatry, shed light on the ways in which genomic differences may contribute to ADHD symptoms.
Using postmortem brain tissue for the first time to investigate ADHD, researchers gathered gene-level information to explore the influence of genes on cell function and symptoms. Investigating gene expression through RNA sequencing, the scientists studied the caudate and frontal cortex of the brain, two connected regions that are crucial in attentional control and management. Differences in the activity and structure of these regions of the brain in individuals with ADHD have been established through previous research.
Gustavo Sudre, Ph.D., associate investigator in the Social and Behavioral Research Branch in NHGRI’s Intramural Research Program, who led this study, noted that multiple studies point toward the expression of the same genes in individuals with ADHD and other neurological conditions. “Interestingly, these gene-expression differences were similar to those seen in other conditions,” he said. “Which may reflect differences in how the brain functions, such as in autism.”
The study marks an important advancement in ADHD research. While past studies have successfully identified genes associated with ADHD, they have not previously studied how genomic differences contribute to symptoms. “This allows us to inch closer to understanding how genomic differences alter gene expression in the brain and contribute to ADHD symptoms,” said Philip Shaw, M.D., Ph.D., senior investigator in the Social and Behavioral Research Branch at NHGRI, who supervised the study.
Shaw also pointed out the value of conducting research on postmortem brain tissue, which can be difficult to access due to limited donations. “Such postmortem studies have accelerated our understanding of other mental health challenges,” he said, “but to date no such studies have looked at ADHD until now.”
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1Sudre, G., Gildea, D.E., Shastri, G.G. et al. Mapping the cortico-striatal transcriptome in attention deficit hyperactivity disorder. Mol Psychiatry (2022). 1 https://doi.org/10.1038/s41380-022-01844-9