ADHD News & Research

Genes (Not Parenting Or Environment) Are Likely Cause of ADHD

Genetic patterns found in more than 20 percent of subjects with ADHD point toward a genetic cause for the disorder — and may open up pathways for new treatment strategies, researchers say.

November 9, 2016

Genetic mutations on specific genes — known as glutamate receptor metabotropic (GRM) network genes — may play an important role in ADHD diagnoses, a new study finds.

The study examined more than 1,000 children from across the United States; all were between the ages of 6 and 17, and all had documented ADHD diagnoses or symptoms. The children underwent genotyping using saliva samples. This study of the DNA sequence found GRM mutations in 22 percent of all the children — with the prevalence increasing to 25 percent for children younger than 12.

“Our work shows that ADHD is likely due to genes. It’s not due to parenting, not due to some environmental causes,” said study author Josephine Elia, MD. “We are very excited about the results. We found these variations in over 20 percent of the sample, and this supports that these are very important pathways for the disorder.”

Elia has conducted similar work in the past, finding GRM mutations in at least 10 percent of previous studies’ samples. The increase in this more recent sample is encouraging, she says. “Our current study replicates the first study and shows the actual prevalence of these variants in the general ADHD population.”

Medications that specifically target these genes are currently in development, Elia said — providing new options for children who haven’t found success with the current field of stimulants and non-stimulants. One drug, a glutamatergic agonist, has tested as safe and effective in a preliminary trial with 30 kids.

“This new drug differs because it basically targets the glutamatergic pathways that we are finding are dysfunctional in ADHD,” Elia said. “The kids in our phase 1 study who had the mutations responded very well, and the side effect profile is much better than with the current drugs.”

“The goal is rather than using medicines that target everything in the brain, like Ritalin and Adderall, that cause a lot of side effects, to use medicines that are more targeted in hopes of decreasing the risk of these side effects,” she said.

The findings were presented at the 63rd Annual Meeting of the American Academy of Child and Adolescent Psychiatry (AACAP).