ADHD gene may be the link to daydreaming

Attention deficit-hyperactive disorder includes difficulty with mental focus. People describe it as daydreaming or mind-wandering instead of concentrating on the task at hand. Now researchers think they have identified a gene that is responsible for this specific characteristic of the disorder.

People who inherit two copies of a particular form of the gene called DAT1 10 are thought to be at greater risk for developing ADHD than people who inherit another form, called DAT1 9. Researchers found that among people with two copies of DAT1 10 (which the scientists term 10/10 carriers), the brain produces excess amounts of dopamine transporters, which results in less dopamine being available to reach brain cells and pass on a signal. Dopamine is important for acting as a gatekeeper in the transfer of information between regions of the brain.

Functional MRI scans of 38 people found that among the DAT 10/10 carriers, the mind-wandering areas of the brain tended to communicate with regions performing memory tasks more strongly compared with the brain activity seen among the participants who carry one DAT1 9 gene allele and one DAT1 10 allele.

“Dopamine from the 10/10 carriers was not doing a good enough job in preventing the mind wandering regions from interfering with memory performance regions, resulting in less efficient cognition,” the lead author of the study, Evan Gordon, of Georgetown University Medical Center, said in a news release.

Being a DAT 10/10 carrier doesn’t mean a person has ADHD, Gordon said. But it contributes to one characteristic of the disorder. It’s most likely that a number of genes variants cause ADHD.

The study was presented Tuesday at the annual meeting of the Society for Neuroscience.

Related: New research fuels skepticism (and questions) about those ADHD diagnoses.

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