human 44 female 38 male 37 Humans 34 Article 31 attention deficit disorder 28 Attention Deficit Disorder with Hyperactivity 25 Male 25 Female 24 child 22 adolescent 21 major clinical study 21 adult 20 controlled study 20 Child 19 ADHD 17 attention deficit hyperactivity disorder 16 Adolescent 14 psychology 13 Adult 12 physiology 11 attention 8 attention-deficit/hyperactivity disorder 8 Attention-deficit/hyperactivity disorder 7 anxiety disorder 7 nuclear magnetic resonance imaging 7 school child 7 Attention 6 United States 6 executive function 6