attention-deficit/hyperactivity disorder

Introduction
Symptoms
Treatment
Causes
Controversy—mental disorder or state of mind?

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Labeled anatomical diagram of the human brain in sagittal section, medial view, showing internal structures such as the corpus callosum, cerebellum, ventricles, brainstem, and other key regions.

At a Glance

attention deficit (hyperactivity) disorder summary

Quizzes

Diseases, Disorders, and More: A Medical Quiz

44 Questions from Britannica’s Most Popular Health and Medicine Quizzes

Related Questions

At what age do symptoms of attention-deficit/hyperactivity disorder usually need to be present for diagnosis?
Can attention-deficit/hyperactivity disorder continue into adulthood?
Does having attention-deficit/hyperactivity disorder mean that a person has low intelligence?
How are behavior problems in children evaluated in a developmental context?
How can ADHD affect an adult’s work and social relationships?
How can cognitive behavioral therapy help people with attention-deficit/hyperactivity disorder?
How can standard school and work environments create difficulties for people with ADHD?
How common is ADHD among children and adolescents in the United States?
How common is attention-deficit/hyperactivity disorder among children worldwide?
How do bupropion and atomoxetine affect norepinephrine in the brain?
How do the caudate nuclei differ in some boys with attention-deficit/hyperactivity disorder?
How does the corpus callosum differ in some boys with attention-deficit/hyperactivity disorder?
How is activity in the left anterior frontal lobe different in some adults with ADHD?
How likely is a child with ADHD to have a parent who also has ADHD?
How likely is a child with ADHD to have a sibling who also has the condition?
How long do long-acting ADHD stimulant medicines usually last?
How long do short-acting ADHD stimulant medicines usually last?
How might delayed development of an impulse-inhibition circuit explain ADHD symptoms?
Is sugar considered a proven cause of attention-deficit/hyperactivity disorder?
What changes can occur when an ADHD medication dose begins to wear off?
What differences in blood flow have been observed in the brains of adults with ADHD?
When did the American Psychiatric Association introduce the term attention deficit disorder?
When did the American Psychiatric Association rename attention deficit disorder as ADHD?
Which inherited factors are linked to attention-deficit/hyperactivity disorder?
Which symptoms are commonly associated with attention-deficit/hyperactivity disorder (ADHD)?
Why are theories blaming bad parenting for attention-deficit/hyperactivity disorder not supported by strong evidence?
Why can ADHD make it difficult to finish schoolwork or other tasks?
Why do some researchers think ADHD-related traits may have had an evolutionary advantage?
Why is a child’s age important when professionals assess behavior problems such as hyperactivity?
What is the Oedipus complex?
Does the Oedipus complex apply to girls?
Is the Oedipus complex real?
What causes narcolepsy?
What are common symptoms of depression?
How does depression differ from grief or mourning?
What are some causes of depression?
What are the main treatments for depression?
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How is polio transmitted?

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External Websites

Social Sciences Libretexts - Attention-Deficit/Hyperactivity Disorder
CDC - Attention-Deficit/Hyperactivity Disorder
Patient - ADHD in Children
National Institute of Mental Health - Attention-Deficit/Hyperactivity Disorder
Mayo Clinic - Attention-Deficit/Hyperactivity Disorder (ADHD) in Children
Cleveland Clinic - Attention-Deficit/Hyperactivity Disorder (ADHD)
National Center for Biotechnology Information - Attention Deficit Hyperactivity Disorder
Verywell Health - What is ADHD?

Britannica Websites

Articles from Britannica Encyclopedias for elementary and high school students.

attention-deficit/hyperactivity disorder (ADHD) - Student Encyclopedia (Ages 11 and up)

attention-deficit/hyperactivity disorder

behavioral syndrome

Also known as: ADD, ADHD, attention deficit disorder

Written and fact-checked by

Britannica Editors

Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree....

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Last updated

Nov. 7, 2026 •History

attention-deficit/hyperactivity disorder (ADHD), a behavioral syndrome characterized by inattention and distractibility, restlessness, inability to sit still, and difficulty concentrating on one thing for any period of time. Attention-deficit/hyperactivity disorder (ADHD) most commonly occurs in adolescents and children, though adults may also be diagnosed with the disorder. ADHD is three times more common in males than in females and occurs in approximately 5 to 7 percent of children worldwide. Although behaviours characteristic of the syndrome are...

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