Guide · Understand International
ADHD: understanding attention, impulsivity and functioning
ADHD attracts more contradictory claims than almost any other subject, including about how common it is. This guide sticks to what is documented: what the condition covers, why the figures vary so widely between studies, and what changes concretely for a child day to day. It makes no diagnosis and discusses no treatment.
Key points
- ADHD is described along three dimensions: inattention, hyperactivity and impulsivity, present to widely varying degrees.
- Diagnosis rests on clinical criteria (DSM, ICD) and belongs to professionals alone.
- Prevalence estimates sit around 5% to 8% in children, but heterogeneity between studies is VERY high.
- Which diagnostic criteria are used changes the resulting figure substantially.
- Inattention is not an absence of attention: it is difficulty DIRECTING and SUSTAINING attention where the situation requires it.
What the three dimensions cover
Inattention shows up as instructions lost along the way, tasks started and not finished, belongings forgotten. It often sits alongside stretches of intense focus on things of interest: not a contradiction, and one of the most common sources of misunderstanding.
Hyperactivity does not always look like a child running. It can be quiet: shifting on a chair, handling everything within reach, talking a great deal.
Impulsivity is acting before weighing things up: answering before the question ends, interrupting, starting without preparing. It connects directly to inhibition, one of the core executive functions.
Why the figures vary so much
A recent meta-analysis puts prevalence at 7.6% among 3 to 12 year olds (95% confidence interval: 6.1 to 9.4%) and 5.6% among 12 to 18 year olds (4.8 to 7%).
But those averages cover considerable heterogeneity between studies, around 98% on the measure used for it. In other words, the studies are not quite measuring the same thing.
The main explanation is the CRITERIA used: in children, prevalence reaches 11.3% under DSM-5 criteria against 7.7% under DSM-IV. Sample size, study year and location also weigh in.
None of this means ADHD is a statistical invention. It means a single figure quoted without its criteria or its interval does not teach you much.
What you can observe
- The times of day when attention gives way, rather than the sheer number of forgotten things.
- The difference between a chosen activity and an imposed task.
- What happens when an instruction has several steps.
- The gap between impulse and action, and what sometimes lengthens it.
- The knock-on effects: tiredness, self-esteem, relationships with other children.
What helps day to day
-
Break instructions up and give them when they are needed, rather than all at once.
-
Make time visible: a timer says more than "hurry up".
-
Reduce what captures attention involuntarily around the task, before asking for more effort.
-
Build in chances to move rather than fighting the movement.
-
Praise precisely what was done, rather than effort in general.
When outside support can help
- If difficulties appear across SEVERAL settings (home, school, activities) and persist.
- If they affect learning, sleep or relationships.
- If the child becomes self-critical or avoids situations where they fail.
- The doctor who follows your child is usually the first person to turn to for direction.
Go further with AtyKids
Official sources
- PubMed Central · The global prevalence of ADHD in children and adolescents: a systematic review and meta-analysis
- Annual Review of Psychology · Diamond, A. (2013). Executive Functions
Information reviewed on August 20, 2026.
Practical AtyKids guidance, distinct from official information. When in doubt, refer to the official source and to the professionals following your child.
AtyKids supports the adult, without ever making a diagnosis or replacing professionals.