Childhood neurocognitive markers may be able to help identify siblings of people with attention-deficit/hyperactivity disorder (ADHD) who will develop late-onset ADHD, researchers found in a study published in The Journal of Child Psychology and Psychiatry.
“There is an increased interest in ‘late‐onset’ attention‐deficit/hyperactivity disorder (ADHD), referring to the onset of clinically significant ADHD symptoms after the age of 12 years,” wrote Shahrzed Ilbegi, PhD, of Radboud University Medical Center, Nijmegen, The Netherlands, and colleagues. “This study aimed to examine whether unaffected siblings with late‐onset ADHD could be differentiated from stable unaffected siblings by their neurocognitive functioning in childhood.”
The 6‐year prospective, longitudinal study used the Dutch part of the International Multicenter ADHD Genetics (IMAGE) study. It included 193 people with childhood‐onset persistent ADHD, 34 of their siblings with late‐onset ADHD, 111 of their stable unaffected siblings, and 186 healthy controls. Participants had a mean age of 11.3 years when entering the study and 17.01 years at follow-up.
At baseline and 6 years later, the study team assessed several neurocognitive functions, including time reproduction, reaction time variability, time production variability, reaction time speed, motor control, and working memory.
Researchers found that siblings with late‐onset ADHD, like participants with childhood‐onset ADHD, showed longer reaction times and/or higher error rates on all neurocognitive measures at baseline and follow‐up, when compared with healthy controls. They also had greater reaction time variability and timing production variability, compared with stable unaffected siblings, at baseline.
“For unaffected siblings of individuals with ADHD, reaction time variability and timing production variability may serve as neurocognitive marker[s] for late‐onset ADHD,” researchers wrote.