4.4 million children and adolescents in the United States have been diagnosed with attention deficit hyperactivity disorder (ADHD) and more than half are treated with medication. Most ADHD medications are stimulants, which activate the sympathetic nervous system (SNS). SNS activation is closely associated with vascular functional and mechanical abnormalities. Therefore, ADHD medications, via instigating SNS activation and altering the hemodynamic profile, may have untoward effects on the vasculature and increase risk of developing cardiovascular disease in children and adolescents who use them.