Is ADHD Genetic? What We Know About Genes & ADHD

What Is ADHD and How Does It Affect the Brain?

ADHD (Attention-Deficit Hyperactivity Disorder) is a neurodevelopmental condition that causes difficulty with attention and/or hyperactivity and impulsivity. ADHD is split into three different presentations: predominantly inattentive, predominantly hyperactive‑impulsive, and combined. This means it can look quite different for different people.

When it comes to ADHD brains, it’s hard to see clear, individual differences on a brain scan. However, larger datasets reveal that people with ADHD display differences in certain brain functions, especially those involved in attention, impulse control, and motivation. 

According to research, in ADHD:

• The brain’s attention and executive‑function networks may be underactive during tasks that require sustained focus.
• The brain’s reward system often responds differently, needing stronger or more immediate stimulation to stay engaged.
• Dopamine and norepinephrine (chemicals that help regulate attention and motivation) tend to work differently.
• The prefrontal cortex (involved in planning and self‑control) may develop or activate differently compared to people without ADHD.

As you can see, many parts of the brain are thought to contribute to ADHD, and there isn’t a single, defining marker that confirms it.

Is ADHD Genetic or Environmental?

There’s a lot of debate around whether ADHD is genetic or environmental; however, most experts agree that ADHD stems from a mix of the two. 

The Impact of Genetics

Research shows ADHD is highly genetic, with a heritability of around 80%. This means genes play a big role in how likely someone is to develop it. But that doesn’t mean every case is directly inherited. While a large majority of people inherit ADHD‑related traits from their parents, in some cases, genetic differences may arise on their own during development.

The Impact of Environment

A person’s environment is also thought to play a part in ADHD, but less so than genetics. When we use the word “environment”, we’re referring to any external factor that affects how the brain develops, not just the environment in which a person was raised. Environmental factors tend to be categorised into two areas:

1. Biological factors: These are things that happen during pregnancy or early infancy, such as premature birth, low birth weight, or exposure to environmental toxins like lead. These can physically impact the brain’s development.
2. Social & lifestyle factors: While there’s no clear evidence that factors like home life, school structure, or too much screen time cause ADHD, some researchers suggest poor habits may influence ADHD symptoms and how well a person is able to manage them.

While the exact causes of ADHD can be tricky to pin down, research is always moving forward, helping us move away from old myths and towards a clearer picture of how different brains work.

Why ADHD Can Run in Families

To understand why it is ADHD often runs in families, it’s important to recognise that ADHD is “polygenic”. This means it’s influenced by multiple gene types, rather than just one. If a parent or both parents carry a combination of these genes, there is a strong likelihood that a child will have ADHD too. According to research:

• Twins are more likely to share ADHD: If one identical twin has ADHD, the other often does too (much more than fraternal twins).
• If your sibling has it, you might too: Children are nine times more likely to have ADHD if they have a sibling with the condition compared to those without an affected sibling.
• ADHD can be inherited from either parent: Mothers and fathers pass on the risk equally.

When to Seek Support for ADHD

It’s not easy reaching out for help when you’re battling ADHD challenges. But if ADHD is making life a struggle, finding the right support can make a world of difference. You might want to seek support if:

• ADHD is affecting your daily life, e.g. at home or work
• Your ADHD traits are becoming more pronounced or challenging over time
• You’re exhausted or burnt out from ADHD masking
• You have a parent with an ADHD diagnosis or who has similar traits

Support can look like many different things. It can mean working with an ADHD professional or coach to get help with certain behaviours or traits. It can mean speaking to your employer about ADHD accommodations. Or, if you don’t have a formal diagnosis, it might mean undergoing an assessment for ADHD, either privately or via your GP and Right to Choose. 

Not everyone with ADHD traits chooses to go down the diagnosis route, and that’s okay, too. What’s most important is that you find ways to manage daily challenges and live a life that’s happy and fulfilling.

FAQs

Is ADHD genetically proven to be a biological condition?

Yes. While ADHD is diagnosed based on behavioural symptoms, the underlying cause is deeply rooted in biology and genetics. It’s officially classified as a neurodevelopmental disorder, meaning it stems from how the brain grows and wires itself.

Is ADHD inherited from a mother or father?

ADHD can be inherited from either parent. There’s no single “ADHD gene” that lives exclusively on the mother’s or father’s side. Because ADHD is polygenic (meaning it’s caused by lots of tiny genetic variations added together), a child usually inherits a unique mix of these variations from both parents.

If I have children, will they get ADHD too?

If you have ADHD, your children have a significantly higher chance of having it than the general population, but it’s not a guarantee. Genetics determine the likelihood, but the final outcome is based on a complex mix of DNA and individual development.