Getting to Long-Term Effectiveness and Safety of Attention-deficit Hyperactivity Disorder Medications.

Attention-deficit hyperactivity disorder (ADHD) medication use has dramatically increased in youth worldwide. Recent prevalence data in some European countries show expanded use with one country now matching US usage. Still, substantial geographic differences by country remain regarding the extent to which children receive ADHD medications. These geographic differences by country raise research questions about which country's prevalence data represents appropriate medication use. We urgently need country level studies to contribute to our understanding of an appropriate prevalence of ADHD medication use.