ADHD stands for attention-deficit/hyperactivity disorder. The name is unhelpful — it sounds like a shortage of attention, which is not quite what people experience. A more useful way to put it: ADHD is a difference in how the brain regulates attention, activity and impulses.
Health agencies classify it as a neurodevelopmental condition. The World Health Organization lists it under neurodevelopmental disorders in the ICD-11, and the CDC calls it "one of the most common neurodevelopmental disorders of childhood", noting that symptoms start in childhood and often last into adulthood.
The three presentations
Clinicians describe ADHD in three forms, depending on which symptoms are strongest when someone is assessed:
- Predominantly inattentive — difficulty holding attention, staying organised, finishing what was started.
- Predominantly hyperactive-impulsive — restlessness, acting before thinking, difficulty waiting.
- Combined — both sets together.
The CDC notes that symptoms can change over time and may look different in adults. The person who could not sit still at eight may, at twenty-eight, be the person who cannot stop taking on new projects.
What it is not
It is not a shortage of effort. This is the most common misunderstanding, and the most expensive one. The World Federation of ADHD International Consensus Statement — a review restricted to meta-analyses and very large studies — opens by stating that misconceptions about ADHD stigmatise affected people and delay treatment.
It is not caused by sugar, screens, or "spoiling" a child. The CDC says the causes are unknown but lists the risk factors research has identified: genetics, which it says play an important role; environmental exposures such as lead; alcohol and tobacco use during pregnancy; child health conditions including head injuries; and parental mental health and family environment. Sugar and screen time are not on that list. Screen time appears on the CDC page only as something worth limiting as part of general healthy habits, not as a cause.
It is not rare, and it is not only a children's thing. The consensus statement puts ADHD at about 5.9% of youth and 2.5% of adults. A separate global meta-analysis estimated persistent adult ADHD — meaning it began in childhood and continued — at 2.58%, and found that prevalence falls as people get older.
It is not an explanation for everything. Trouble concentrating is one of the least specific symptoms in all of medicine. Poor sleep, untreated anxiety, depression, grief, thyroid problems, chronic stress, hunger, and simply being in a job that does not suit you all produce the same surface complaint. This matters more than it sounds: if you decide "it's just my ADHD" and it is actually untreated anxiety, you have talked yourself out of the help that would have worked.
Why a diagnosis has a threshold
NICE, the UK body that writes clinical guidelines, sets out what has to be true before ADHD is diagnosed. The symptoms must meet the diagnostic criteria in DSM-5 or ICD-11, they must cause "at least moderate psychological, social, or educational or occupational impairment", and they must be "happening often, occurring in 2 or more important settings including social, familial, educational or occupational settings".
That last part is the one worth sitting with. One setting is not enough. If you are scattered at a job you hate but sharp everywhere else, the job is the more likely explanation. If the same pattern follows you into school, work, home, friendships and money — that is the pattern a clinician is looking for.
NICE is also explicit that a diagnosis "should not be made solely on the basis of rating scale or observational data". An online quiz cannot diagnose you. Neither can this page.
Why the word "lazy" stuck
In a lot of African homes, including plenty of Nigerian ones, there was no vocabulary for this. There was a bright child who did not finish things, and there was a word for that child, and the word was lazy. Sometimes it was stubborn. Sometimes it was "you just don't want to face your book".
That naming was not cruelty. Most of the adults doing it had never heard the alternative explanation — specialist assessment in Nigeria has been concentrated in cities and teaching hospitals, and the researchers who studied ADHD in rural south-eastern Nigeria said so directly in their conclusions.
But a wrong name has a cost. If the explanation you grew up with was character, then every difficulty became evidence about who you are, rather than information about how you work. That is the part worth putting down.
What actually helps
The honest answer is: it depends on what is going on, which is why the assessment question matters. NIMH describes standard treatment as medication and psychosocial interventions, with cognitive behavioural therapy, parent training and school-based support among the examples.
Meanwhile — and this is true whether or not ADHD turns out to be the explanation — the practical strategies on this site are worth trying. Making a first step smaller, putting reminders outside your head, and asking for help in specific words are useful to anyone whose attention does not behave.