New Study Highlights Role of Genetics in ADHD

Genetics can influence the time that attention-deficit hyperactivity disorder (ADHD) is first diagnosed as well as its persistence into adulthood among affected children, according to a study appearing in this week's Nature Genetics. ADHD is primarily a neurodevelopmental disorder affecting children, although about two-thirds of those affected will continue to have the condition into adulthood and a small number of people are diagnosed as adults. To better understand the condition, a team led by scientists from Aarhus University performed an in-depth characterization of the polygenic architecture of childhood, persistent, and late-diagnosed ADHD in a large Danish population-based case-cohort sample of ADHD cases and controls. The researchers uncover differences among the groups with respect to common ADHD risk variants and rare protein-truncating variants as well as several significant differences in genetic overlap of ADHD subgroups with other phenotypes. This includes an increased load of autism risk variants in individuals with childhood compared with late-diagnosed ADHD and a larger genetic overlap of persistent and late-diagnosed ADHD with depression compared with childhood ADHD. "Overall, we have identified genetic heterogeneity among ADHD subgroups, and our findings suggest that genetic factors influence the time of first ADHD diagnosis, persistence of ADHD into adulthood and comorbidity patterns," the study's authors write.