Common childhood-onset disorder characterised by inattention, hyperactivity, and/or impulsivity demonstrated across 2 or more settings (such as home and school).
Some impairment must be present by 12 years of age and 60% to 70% of patients have persistent functional impairment into adulthood.
Diagnosed by clinical history, which should include information from multiple sources, including parents, carers, and teachers.
Mainstay of treatment is stimulant medication, which can be effective in 85% of patients; non-stimulants are less often effective, but may have other advantages in terms of duration of action or in special populations.
Stimulant medications have been associated with cardiovascular side effects. These should be monitored in children with heart conditions.
ADHD is a problem of inattention, hyperactivity, and impulsivity according to the American Psychiatric Association.  This disorder is recognised globally and is referred to as hyperkinetic disorder in Europe and other countries that use the WHO classification system.  ADHD is a chronic condition with symptoms that begin in early childhood but often persist into adult life. A key element of the definition is functional impairment across 2 or more domains, most often in school and at home.  As a result, ADHD can limit academic, interpersonal, and occupational success and can also lead to greater risk-taking and accidents.  In addition, patients with ADHD are more likely to have co-existing psychiatric disorders such as oppositional defiant disorder (ODD), conduct disorder, substance abuse, and possibly mood disorders, such as depression and mania.      
Associate Professor of Neurology and Pediatrics
Director, Pediatric Neuropsychiatry Program
Children's Hospital of Philadelphia
LWB declares that he has no competing interests.
College of Health Professions
BPD declares that he has no competing interests.
Academic Specialist Registrar
Academic Department of Paediatrics and Obstetrics and Gynaecology
MMH declares that he has no competing interests.
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