Is ADHD hereditary — if I have it, will my kid definitely have it too?

Both my kids ended up getting diagnosed after I did, which apparently isn't uncommon, parent gets diagnosed as an adult and it opens the door to actually recognizing it in the kids sooner than it would've been caught otherwise. Not guaranteed, but definitely wasn't random in my family.

ADHD is considered one of the more heritable neurodevelopmental conditions, research consistently shows a strong genetic component, but 'heritable' doesn't mean 'guaranteed' or even predictable in a simple, direct way like some single-gene traits. It's polygenic, meaning many different genes each contribute a small amount of risk, rather than one specific 'ADHD gene' being passed down in a clean pattern. Having a parent with ADHD does meaningfully increase a child's likelihood of also having it compared to the general population, but it's a probability shift, not a guarantee either way. Plenty of people with ADHD have kids without it, and plenty of people without any diagnosed ADHD have kids who do. Environmental and other factors also play some role alongside genetics, though genetics is considered the larger contributor overall based on twin and family studies specifically. Practically, what this might mean for you: it could be worth being a bit more attentive to early signs in your kid down the line, not out of anxiety, but because knowing there's elevated familial likelihood means earlier recognition and assessment is more realistic if signs do show up, rather than symptoms getting dismissed the way a lot of parents' own childhood symptoms were.