Attention deficit hyperactivity disorder (ADHD, similar to hyperkinetic disorder in the ICD-10) is a neurodevelopmental psychiatric disorder in which there are significant problems with executive functions (e.g., attentional control and inhibitory control) that cause attention deficits, hyperactivity, or impulsiveness which is not appropriate for a person's age. These symptoms must begin by age six to twelve and persist for more than six months for a diagnosis to be made. In school-aged individuals inattention symptoms often result in poor school performance. Although it causes impairment, particularly in modern society, many children have a good attention span for tasks they find interesting.
Despite being the most commonly studied and diagnosed psychiatric disorder in children and adolescents, the cause in the majority of cases is unknown. The World Health Organization estimates that it affected about 39 million people as of 2013. It affects about 6–7% of children when diagnosed via the DSM-IV criteria and 1–2% 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 in boys than in girls. About 30–50% of people diagnosed in childhood continue to have symptoms into adulthood and between 2–5% of adults have the condition. The condition can be difficult to tell apart from other disorders as well as that of high normal activity.
ADHD management recommendations vary by country and usually involves some combination of counseling, lifestyle changes, and medications. The British guideline only recommends medications as a first-line treatment in children who have severe symptoms and for them to be considered in those with moderate symptoms who either refuse or fail to improve with counseling. Canadian and American guidelines recommend that medications and behavioral therapy be used together as a first-line therapy, except in preschool-aged children. Stimulant therapy is not recommended as a first-line therapy in preschool-aged children in either guideline. Treatment with stimulants is effective for up to 14 months; however, its long term effectiveness is unclear. Adolescents and adults tend to develop coping skills which make up for some or all of their impairments.
ADHD, its diagnosis, and its treatment have been considered controversial since the 1970s. The controversies have involved clinicians, teachers, policymakers, parents, and the media. Topics include ADHD's causes and the use of stimulant medications in its treatment. Most healthcare providers accept ADHD as a genuine disorder, and the debate in the scientific community mainly centers on how it is diagnosed and treated. Before 1987 the condition was known as attention deficit disorder (ADD).