Article 21 human 21 major clinical study female 20 male 20 controlled study 16 attention deficit disorder 15 Humans 14 child 14 Attention Deficit Disorder with Hyperactivity 12 adolescent 12 Male 11 Child 10 Female 9 attention deficit hyperactivity disorder 8 ADHD 7 adult 7 psychology 7 school child 7 Adolescent 6 anxiety disorder 6 United States 5 central stimulant agent 5 comparative study 5 attention 4 cohort analysis 4 methylphenidate 4 randomized controlled trial 4 Anxiety Disorders 3 Attention 3