Cohorts

We included data from the Healthy Brain Network (HBN), Adolescent Brain and Cognitive Development (ABCD), Neurobehavioral Clinical Research (NCR), National Consortium on Alcohol and Neurodevelopment in Adolescence (NCANDA), and Human Connectome Project – Developmental (HCP-D) datasets (14–19). The Supplemental Methods summarize each study’s recruitment methods and sampling strategies, protocols and image acquisition parameters. All studies had IRB/ethical approval and acquired informed assent and/or consent using IRB approved procedures. For the questionnaire-based analyses, the main inclusion criteria were ages ≥6 years and ≤18 with an IQ>70, availability of all covariate data, and availability of parent/caregiver completed questionnaire CBCL data. In the primary analyses we consider raw scores of the six empirical scales which are based on factor analyses of the items and include attention problems (11, 12). Raw scores were analyzed in this study because age and sex were included as covariates in the regression models. For the case-control analyses, ADHD was defined using DSM criteria (diagnostic data were available for all cohorts except HCP-D). Unaffected controls were those with no ADHD diagnosis and not on any psychotropic medications. See Supplemental Methods for further details.