Yes, ADHD is strongly hereditary: the NHS says it often runs in families, and twin studies put its heritability at around 74%, but genes alone do not decide it; environment also plays a part.
What “hereditary” actually means here
ADHD is one of the most heritable mental-health conditions, but there is no single “ADHD gene” a doctor can test for. It is polygenic, which means many small genetic differences act together, and a child inherits a tendency rather than a certainty. The NHS lists genetics as a cause and notes that ADHD may be caused by genetic differences and often runs in families.
How strong the family link is
Twin studies put the heritability of ADHD at roughly 74%, which is high. In practice, a child who has a parent or sibling with ADHD is several times more likely to have it too. The UK charity ADHD Aware notes that close relatives may be up to nine times more likely to have it.
Genes load the dice, but they are not destiny
A strong family link does not mean your child will definitely have ADHD. Other factors shape whether and how it shows up, including being born premature, having epilepsy, and a brain injury, all of which the NHS lists alongside genetics. Environment and development can influence how strongly symptoms appear, even though they do not cause the underlying condition. The NHS is also clear that the cause of ADHD is not always known, so a child can have it with no obvious family history at all.
It is worth being clear about what does not cause ADHD. It is not the result of parenting style, diet, screen time, or “bad behaviour”. ADHD is a neurodevelopmental condition, and seeing it as inherited rather than chosen takes the blame off both you and your child.
Why parents often see it in themselves
Many adults recognise ADHD traits in themselves only after their child is assessed. Because it runs in families and was under-diagnosed in earlier generations, especially in girls and women, a child's referral is often the first time a parent connects the dots about their own childhood. That is common, and it does not change anything about your child's assessment.
Where the law comes from
This page is general information, not clinical or legal advice.