Attention deficit hyperactivity disorder (ADHD, similar to hyperkinetic disorder in the ICD-10) is a psychiatric disorder of the neurodevelopmental type in which there are significant problems of attention and/or hyperactivity and acting impulsively that are not appropriate for a person's age. These symptoms must begin by age six to twelve and be present for more than six months for a diagnosis to be made. In school-aged individuals the lack of focus may result in poor school performance.
Despite being the most commonly studied and diagnosed psychiatric disorder in children and adolescents, the cause in the majority of cases is unknown. It affects about 6 to 7 percent of children when diagnosed via the DSM-IV criteria and 1 to 2 percent when diagnosed via the ICD-10 criteria. Rates are similar between countries and depend mostly on how it is diagnosed. ADHD is diagnosed approximately three times more frequent in boys than in girls. About 30 to 50 percent of people diagnosed in childhood continue to have symptoms into adulthood and between 2 and 5 percent of adults have the condition. The condition can be difficult to tell apart from other disorders as well as that of high normal activity.
A dopamine agonist is a compound that activates dopamine receptors in the absence of dopamine. Dopamine agonists activate signaling pathways through the dopamine receptor and trimeric G-proteins, ultimately leading to changes in gene transcription.