Attention deficit hyperactivity disorder (ADHD) is a developmental precursor for future conduct and other externalizing problems. Despite its familiarity, research in the past decade suggests that refining the ADHD phenotype will yield dividends for clinical prediction and treatment specification as well as mechanistic discovery and theory. ADHD is a useful category, yet it comprises multiple constitutive traits requiring further specification. The field is now poised to shift to a useful…
