Researchers find new clues to what drives ADHD

New Australian and Taiwanese research has for the first time pinpointed where in the brain the communication process breaks down for people with chronic attention deficit hyperactivity disorder (ADHD) – a finding that could change the way people with the disorder are treated in the future.

The study findings have been published in the medical journal Molecular Psychiatry.

Lead researcher and head of the Clinical Brain Networks team at QIMR Berghofer Medical Research Institute, Dr Luca Cocchi, said the study found ADHD symptoms are linked to noisy communication between brain regions in individuals with the disorder.

“Our results suggest that elevated noise in the signal between sensory and cognitive regions of the brain are related to people having trouble maintaining their attention and controlling their hyperactivity,” Dr Cocchi said.

“It’s like when a loudspeaker is not working properly and emits a lot of static, making it harder to understand what is being said.”

The research team used neuroimaging to analyse the brains of 80 adults who had been diagnosed with ADHD as children, but who had never used medication and did not have any other psychiatric disorders or illnesses.

That data was compared to brain images from more than 120 healthy controls of similar intelligence.

“We found no major differences in the brain anatomy of people with ADHD, compared to people without the condition, but there was a change in how the anatomical pathways support the communication between visual, somatomotor, and frontoparietal brain regions,” Dr Cocchi said.

Co-author and senior research officer in QIMR Berghofer’s Brain Modelling team, Dr Paula Sanz-Leon, said they used advanced computer simulations to define the likely cause of the abnormal associations in the brain.

“Computer simulations and brain imaging showed that the greatest difference between people with and without ADHD was in the communication or interaction between the peripheral sensory regions of the brain and their processing hubs,” Dr Sanz-Leon said.

“This would explain why the neural pathways in people with ADHD do not work as effectively and result in erratic messaging.”

Dr Cocchi said the study findings provided important new clues for future research into this sometimes debilitating disorder.

“This could also lead to better treatments. That could be with drugs that reduce neuronal noise or by using non-invasive brain stimulation,” Dr Cocchi said.

“The team now hopes to explore if brain stimulation can be tailored to the individual to reduce the amount of neural noise they experience and improve symptoms.”

ADHD is the most common mental disorder in children and adolescents in Australia according the Australian Institute of Health and Welfare.

ADHD Australia estimates one in 20 Australians have the disorder, with symptoms including inattention, distractibility, hyperactivity and impulsivity.

The research was supported by the NHMRC in Australia, and the Ministry of Technology and Science, the National Health Research Institute and National Taiwan University Hospital in Taiwan.

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