Attention-deficit/hyperactivity disorder (ADHD) traits vary continuously across the general population, yet whether the frontal structural correlates established in clinical ADHD extend to trait variation in nonclinical adults is unknown. Based on meta-analytic evidence, we hypothesized that orbitofrontal gray matter volumes would be negatively associated with hyperactivity traits in 2548 nonclinical Japanese adults (1488 males, 1060 females; aged 23-76 years) who underwent structural MRI and…
