What Could Be the Cause of Attention Deficit Hyperactivity Disorder (ADHD)?

After falling down a rabbit hole full of various information, I compiled a list of bullet points from the information I have found. The links to the papers I have delved into are at the bottom if you want to dive in yourself.

One thing is very clear across the board, and that is ADHD is a neurodevelopmental disorder, which refers to the development of the nervous system, but the overall cause seems to be a mystery.

As it turns out, there isn’t definitive evidence to pinpoint the exact reason for ADHD as of yet, but there are some factors which contribute towards who is more likely to develop this neurological condition.

Some are born with ADHD, and some people can develop this later in life. Some of the factors I’ve come across include genetics, trauma, diet, how the baby is affected in utero during pregnancy, brain trauma, and how the brain chemicals can affect individuals.


Genetics appear to be the highest likelihood of having ADHD, passing down from generation to generation. However, it appears to be complicated on how it is passed down, and scientists are still unable to identify which specific biological markers are responsible for ADHD.

Studies on twins with ADHD show that there is a 60-80% chance of inheriting ADHD, and siblings of those with ADHD have a 26-45.2% chance of also having ADHD.


Trauma could be caused by being born prematurely, witnessing or experiencing abuse, loss, neglect, there are many different experiences that contribute to trauma. In one study, domestic violence was named as one of the main causes.

Childhood trauma or ACEs (Adverse Childhood Trauma) can go hand in hand with ADHD– one can cause the other, a bit like the chicken and the egg question; which came first?


Even though currently there’s no direct link to prove ADHD is caused by diet, but a study has shown that lower levels of iron, zinc, copper and Omega-3 were found in children with ADHD.

Additionally, a “Westernised” diet consisting of fatty foods, refined sugars, higher sodium, and lower fibre content may also be contributing factors- including food additives.


Smoking during pregnancy leads to a 60% higher risk of giving birth to a child with ADHD symptoms in comparison with non-smoking mothers. For heavy smokers, it raises to a 75% chance.

Binge drinking alcohol during pregnancy, or even consuming alcohol in low or moderate amounts, makes it five times more likely of ADHD symptoms occurring. A combination of bingeing and low/medium consumption increases the likelihood to 19%.

Some studies have linked ADHD with prenatal exposure to antidepressants, illicit drugs, caffeine, hypertension medication, and even Paracetamol.

Exposure to stress for pregnant women can lead to higher chance of children with ADHD to have elevated levels of symptoms- this could be caused by the effects of pregnancy complications such as preeclampsia, bleeding, or high blood pressure which of course affect the baby in utero.

The Brain- Trauma and Chemicals

Those with ADHD have different pathways in their brain, which means their wiring will be different to those with a neurotypical brain. It affects people in different ways, such as how they interact socially, how well their memory works, and their ability to focus.
Another factor to consider is that those with ADHD have lower levels of the neurotransmitter dopamine, compared to those without.

Neurotransmitters are the body’s “chemical messengers”, taking chemicals from the nervous system to neurons, and from neurons to the muscle, and in this instance, someone with ADHD will have lower levels of the chemical messages being sent where they are needed.

Dopamine is responsible for motivation and reward. When levels are low, the drive to get things done feels like a massive chore- the thing that feels hard to do we tend to do because there’s normally a reward for getting it done, even if it’s a feeling of accomplishment.

With lower levels of dopamine, that reward part feels lower, or non-existent, which is why a lot of people with ADHD suffer from executive dysfunction. How do you force yourself to do something if there feels as though there is no payoff at the end?

Finally, it’s worth mentioning brain trauma as a contributing factor, but there’s been some contradictions and confusion on this, from what I’ve found.

Severe brain injuries in children can cause ADHD to develop, either in utero or later in life. However, it just could be a similarity in symptoms caused by trauma to the brain in the areas which affect memory issues, shifts in mood, impulsivity, and struggling to focus.

However, it could also be argued that perhaps the child already had ADHD, as further studies on adults with ADHD who also suffered brain trauma didn’t show any significant differences compared to those without ADHD who also suffered from brain trauma.

Final Thoughts

The studies on children with ADHD help us to identify different factors, but no one can say for certain what exactly is going on, however, due to the high number of statistical evidence, it’s most likely to be the genetic factor.

We know that medication helps with ADHD, and this is because they target the affected neurotransmitters- but what works for some may not work for others. Hopefully in the future there will be more studies on adults to help shine a light on other aspects that may not have been discovered primarily in children’s studies.

Thanks for taking the time to read this article, I hope you found it useful! If there’s anything I’ve missed, or if you just want to say hi, drop me a message.

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Other Links on the Topic:

Causes (NHS)

Attention Deficit Hyperactivity Disorder: Causes of ADHD (Web MD)

Causes of and Risk Factors for ADHD (Healthline)

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