Highlights
- Genetics plays a significant role in the development of attention deficit hyperactivity disorder (ADHD), but environmental factors also have an influence.
- The inheritance pattern of ADHD is complex and involves multiple genes.
- Having a biological parent or sibling with ADHD increases the chances of a child having ADHD.
- There are currently no genetic tests available for ADHD, and it is still diagnosed on symptoms by a healthcare professional.
You might be reading this post because you have a parent with ADHD, think you might have similar symptoms, and wonder if ADHD is hereditary. Or, perhaps your child has just been diagnosed with ADHD, and you recognize their behavior in yourself. If this sounds like you, you can also consider taking this free online ADHD screening test.
Another possibility is that you already have an ADHD diagnosis, are thinking of starting a family, and want to know the implications.
Whatever the reason, we’ll answer all your questions about the genetic aspect of ADHD and whether it runs in families.
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What Is the Cause of ADHD? Is It Hereditary?
Attention deficit hyperactivity disorder (ADHD) is a complex disorder that doesn’t have an exact cause. Instead, it is a mixed result of a person’s genes and specific circumstances (environmental factors) that they might have experienced.
The Role of Genetics in ADHD
Evidence suggests ADHD is largely a genetic disease with a well-established
Basically, genetics predispose someone to ADHD, but the person’s environment also has an influence.
Think of ADHD like a chocolate cake:
- Imagine the hereditary aspect and genes being the strict recipe steps that have about an 80% effect on the product outcome.
- But, 20% is influenced by external circumstances: how the batter is mixed, the quality of the ingredients, and whether the oven is working properly.
Every cake made from the same recipe might look or taste slightly different, but they are still chocolate cakes because the basic recipe has the biggest influence on the result.
In the same way, every person with ADHD is different, mostly influenced by genetics but also by circumstances and environmental factors.
How has this been worked out?
Family Studies
Family studies have shown that:
- The child of a parent with ADHD has
about a 57% [2*] chance of also having ADHD. - Siblings of children with ADHD ages 5 to 7 years are 9 times more likely to have ADHD than siblings of their non-ADHD equals.
Identical Twin Studies
Because identical twins have exactly the same genes, any behavioral differences between them can be assumed to have
Adoption Studies
An adopted child shares no DNA with their parents, so this eliminates the genetic side of things. This allows the effect of the shared environment to be assessed on ADHD in adopted and biological children. Adoption studies suggest that genetics outweigh the environment in the risk of developing ADHD.
Interestingly, family and twin studies also show a specific genetic overlap between ADHD and other mental health disorders, such as conduct disorder, oppositional defiant disorder, substance abuse problems, and autism spectrum disorder.
The way ADHD is passed through generations is complex and the result of more than one genetic mutation. It might surprise you that
- 7300 small differences in DNA associated with a slight increase in the risk of ADHD. The more there are in a person, the higher the risk.
- 76 risk genes for ADHD; these specific genes carry a much higher risk for ADHD if inherited.
Most of these DNA differences influence areas in the brain that are important for attention, memory, movement, and reward. In fact, ADHD is classified as a neurodevelopmental, or in simple terms, brain development disorder.
The ADHD Brain
ADHD brains function differently from non-ADHD brains. This is because of how ADHD brains are built and how their nerve cells communicate, changing the way a person with ADHD thinks and behaves.
- Brain Chemistry. Chemical differences in the ADHD brain are related mainly to the neurotransmitter dopamine. Dopamine is a brain chemical that helps someone feel rewarded; it’s a feel-good nerve cell messenger that helps people stay motivated and on track.
Certain areas of ADHD brains have
- Brain Structure. Many brain regions (including the frontal lobes and basal ganglia, although this is not important to know) in ADHD brains
are smaller [8*] than in non-ADHD brains, affecting brain function.
Basal ganglia are important for controlling movement, behavior, and decision-making.
The frontal lobe is important for intelligence and creativity. It is home toworking memory [9*] , which has temporary storage (short-term memory) and an area that can interpret information (executive function). People with ADHD are known to havepoor executive working memory [10*] , which makes it difficult to focus, prioritize, and make logical decisions.
We’ve mentioned that
Other Possible Causes and Risk Factors of ADHD
Some of the other factors that might affect brain development are:
1. Before birth in the womb, if a mother:
- Experiences regular stress and trauma
- Is exposed to pesticides
- Smokes
- Is not eating the correct food to stay healthy
- Has severe infections
2.
- Premature birth
- Low birth weight
- Childhood stroke
- Brain injury
- Lead expose
- Immune response to bacterial infection (streptococcal) affects the basal ganglia
- Childhood abuse or neglect
Some of these, like brain injury, have
Common Misconceptions About the ADHD Causes
We’ve chatted about some of the likely environmental triggers, causes, and risk factors of ADHD that affect brain biology. Now let’s discuss other things that are often thought to be causes but are not.
Lack of Nutrients and Microelements
We’ll first look at nutritional factors as a cause of ADHD because they are controversial. There have been
Obviously, a healthy diet is essential for a healthy brain. Importantly, though, a healthy diet in childhood can have a significant effect on lowering the risk of ADHD diagnosis compared to those who are not. This is particularly true for a
Parenting Practices
A parent’s influence ends with the genetic factors of ADHD. Although poor parenting practices, such as excessive punishment, high control and unrealistic rules, poor boundaries, and low emotional support, may make the ADHD symptoms worse, they do not cause the disorder.
Video Games and TV Watching
Excess time spent on screens is not a cause of attention deficit hyperactivity disorder but, rather, might worsen ADHD symptoms; games and TV act as distractions that make focusing more difficult.
A High Sugar Diet
There has always been a theory that eating too much sugar causes ADHD, but this is not proven. In fact, some studies think that craving for and eating sugar might be a result of the disorder and not a cause of it.
What to Do When You Have a Family History of ADHD
Now that you know genes play a role, and if you have a family history of ADHD, monitor yourself for the symptoms, as
Even though there is a strong genetic link,
Importantly, getting a diagnosis sooner rather than later is critical, as untreated ADHD in adults can have negative effects. So, if you suspect you may have attention deficit hyperactivity disorder, book an appointment today.
FAQs about ADHD and Heredity
Is ADHD inherited from the mother or father?
The genetic component of attention deficit hyperactivity disorder can be
Should people with ADHD have children?
Who is most likely to inherit ADHD?
Remember that although genetics play the biggest role in having ADHD, so does the environment the person is exposed to.
What ethnicity is most likely to have ADHD?
According to a
