Demographic data.

Abbreviations: ADHD, Attention-Deficit/Hyperactivity Disorder (I = inattentive type, HI = hyperactive/impulsive type, C = combined type); AM, Above Median; BM, Below Median; ODD, Oppositional Defiant Disorder; DISC-IV, Diagnostic Interview Schedule for Children-Fourth Edition; CBCL, Child Behavior Checklist; TRF, Teacher Report Form; SES, Socio-Economic Status.aFour children that met DISC-IV criteria for ODD also met criteria for CD;bCBCL unavailable for 2 ControlBelow-median IQ, 2 ControlAbove-median IQ, 11 ADHDBelow-median IQ, 2 ADHDAbove-median IQ in structural MRI sample, for 1 Control and 3 ADHD in DTI sample; TRF unavailable for 5 ControlBelow-median IQ, 8 ControlAbove-median IQ, 12 ADHDBelow-median IQ, 5 ADHDAbove-median IQ in structural MRI sample, for 1 control and 9 ADHD in DTI sample.cMedication histories were available for 87% of ADHDBelow-median IQ and 79% of the ADHDAbove-median IQ children in the structural MRI sample and 87% of ADHD children in the DTI sample. Reported is the percentage of established use in the entire (sub)sample. Corrected duration is calculated as: duration of use in months/((age in months) – 60).