ADHD in children and adults

This page is reference information compiled from the cited sources. It is not medical advice. For any decision about health, diagnosis or care, consult a qualified professional.

What it is

Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterised by symptoms of inattention, hyperactivity, impulsivity, and emotional dysregulation that are excessive and pervasive, impairing in multiple contexts, and developmentally inappropriate. ADHD symptoms arise from executive dysfunction. The disorder is divided into three primary presentations: predominantly inattentive, predominantly hyperactive-impulsive, and combined presentation. ADHD represents the extreme lower end of the continuous dimensional trait of executive functioning and self-regulation. As it is a neurodevelopmental disorder, there is no biologically distinct adult-onset ADHD except for when ADHD occurs after traumatic brain injury.

Key facts

ADHD is characterised by symptoms of inattention, hyperactivity, impulsivity, and emotional dysregulation that are impairing and developmentally inappropriate. The precise causes of ADHD are unknown in most individual cases, but the disorder is primarily genetic with a heritability rate of 70–80%. Symptoms must be present for six months or more to a degree much greater than others of the same age and must be present in at least two settings, directly interfering with functioning. Several symptoms must have been present before age 12 according to DSM-5 criteria. Girls and women with ADHD tend to display fewer hyperactivity and impulsivity symptoms but more symptoms of inattention and distractibility. Symptoms are expressed differently and more subtly as the individual ages, with hyperactivity turning into inner restlessness in teens and adults. People with ADHD of all ages are more likely to have problems with social skills, and about half of children and adolescents with ADHD experience social rejection by their peers.

When to seek professional help

A diagnosis can be hard to ascertain, as it is hard to distinguish between normal levels of symptoms and levels that cause significant impairment in major life activities. Professional help is associated with symptoms that are excessive, pervasive, and developmentally inappropriate, impairing in multiple contexts. It is associated with symptoms that directly interfere with or reduce quality of functioning in settings such as social, school, work, or home. Professional evaluation is indicated when symptoms include academic difficulties and problems with relationships. Professional assessment is relevant when difficulties such as poor professional performance, relationship difficulties, and numerous health risks are present, as these impairments predispose to a diminished quality of life.

Source: Attention deficit hyperactivity disorder (CC BY-SA 4.0 (Wikipedia)), retrieved 2026-08-27.