 Attention deficit hyperactivity disorder is a psychiatric condition involving problems with attention , hyperactivity , and impulsiveness . It is most commonly treated using stimulant drugs such as methylphenidate ( Ritalin ) , whose primary effect is to increase dopamine levels in the brain , but drugs in this group also generally increase brain levels of norepinephrine , and it has been difficult to determine whether these actions are involved in their clinical value . Also there is substantial evidence that many people with ADHD show " biomarkers " involving altered norepinephrine processing . Several drugs whose primary effects are on norepinephrine , including guanfacine , clonidine , and atomoxetine , have been tried as treatments for ADHD , and found to have effects comparable to those of stimulants . 
