ADHD, or attention-deficit/hyperactivity disorder, is a complex condition that affects how the brain develops and also functions. And while many people think that there is only one cause, it doesn’t have just one source, rather it results from a mix of genetic and environmental factors.
ADHD often runs in families, suggesting a genetic component, while other factors include premature birth, exposure to toxins, and early brain injuries. Let’s explore these and other potential causes of ADHD as we answer the question: what causes ADHD?

Is ADHD Genetic?
Yes, ADHD could be genetic, meaning it can run in families. If a parent or another close relative has ADHD, a child is more likely to inherit it as well. Many researchers believe that this link comes from a specific gene that affects how the brain develops and functions, especially in the areas that are related to attention, impulse control, and emotion regulation.
ADHD affects 1 to 3% of children worldwide. This might seem like a relatively small amount of children, but with a population of around 8 billion people, you can see why it is a cause for concern and why so many researchers dedicate time to understanding the causes of ADHD. [1]
Some studies even show that if one identical twin has ADHD, the other has a 60 to 90% risk of having it, too, which explains why many say that it is hereditary. [2]
It is important to note that having a genetic link to ADHD doesn’t necessarily mean that it is predetermined or unchangeable. Knowing that ADHD has a more biological basis can also help reduce the stigma and is instead about how the brain is wired and not laziness or a lack of effort.
Having said that, genetics isn’t the only factor, and ADHD is a complex condition influenced by a mix of biological and environmental influences like exposure to certain toxins, premature birth weight, and other childhood experiences.
The Environmental Causes of ADHD
Although ADHD does have a strong genetic basis that runs in families, this is not always the case for everyone. Environmental factors can also play a big role. Understanding these environmental causes is important, and it can help someone identify any potential triggers and develop better ways to manage the condition.
One of the more critical environmental factors is the exposure to toxins in pregnancy. Things like lead, pesticides, and air pollution can increase the chances of a child developing ADHD as they disrupt the normal growth and development of a baby’s brain, leading to the attention, impulsivity, and hyperactivity issues we see in ADHD.
Other factors, like complications during pregnancy or birth (like being born prematurely or having a low birth weight) can contribute to ADHD. These issues can cause damage to the developing brain and affect the parts responsible for focus, emotional regulation, and self-control.
Exposure to high stress and trauma can also play a role. Chronic stress can change the brain’s chemistry and structure, making it harder for a child to develop essential skills like organization and impulse control. Abuse, neglect, and other traumatic events can also disrupt normal brain development and contribute to ADHD symptoms.
ADHD is rarely caused by one factor and is usually a combination of genetic predisposition and environmental influences that shape our experiences with the condition. By being aware of the different factors, we can work to minimize the risks and rather provide the best possible support.
The Neurobiological Causes of ADHD
There is a definite science behind the causes of ADHD, and many researchers have found that ADHD is closely linked to a chemical in the brain called dopamine. Dopamine is that all-important chemical that helps us stay focused and motivated. For people with ADHD, however, the brain often doesn’t produce or use dopamine as well as it should.
The brains of people with ADHD are a bit different in their structure and function. The prefrontal cortex – the part of the brain responsible for focus, decision-making, and self-control – is often smaller and less active. This also means that the communication pathways in the ADHD brain may not work as smoothly, making it challenging to switch between tasks and ignore any distractions that may come up.
Brain differences help explain why ADHD can feel like a constant struggle to stay organized and on track with everything that needs to be done. But, it’s important to understand that ADHD isn’t about being “less than,” since it’s just how the brain works for some people. Knowing the proper science behind ADHD is also helpful in guiding treatments like medication and therapy, which aim to balance brain chemicals like dopamine and strengthen brain function.
Prenatal and Early Life Risk Factors of Developing ADHD
There are certain things during pregnancy and early childhood that may increase the chances of someone developing ADHD. And while they don’t directly cause ADHD, they certainly contribute to changes in brain development, raising the risk of ADHD.
During Pregnancy
If a pregnant woman smokes, drinks alcohol, or uses drugs, these can interfere with the baby’s developing brain. High stress, poor nutrition, and exposure to toxins like lead or pesticides can also increase the risk, and so too can premature birth and low birth weight.
Early Childhood
The environment that a young child is exposed to matters, too. Babies and toddlers who experience neglect, abuse, or significant stress may also have disruptions in their brain development. This, coupled with exposure to lead and other toxins, frequent infections, and head injuries during early childhood, can also increase the chances of ADHD.
Other Factors
Here are a few other risk factors for developing ADHD:
- Having a close family member with ADHD. This can be a parent, older sibling, or twin. ADHD often runs in families.
- Experiencing a traumatic brain injury. Damage to the brain can lead to ADHD-like symptoms.
- Being born to an older mother. Maternal age plays a big role in the risk of developing ADHD.
Can Diet and Nutrition Affect the Development of ADHD?
The foods we eat and the nutrients we get (or don’t get) may just play a role in the development of ADHD. Researchers have found that children with ADHD tend to have lower levels of specific vitamins, minerals, and fatty acids in their bodies compared to children without ADHD.
The most essential vitamins and minerals are:
- Omega-3s: Crucial for healthy brain development and communication between brain cells.
- Iron: Needed to produce dopamine and other neurotransmitters that regulate energy and attention levels.
- Zinc: Helps regulate the production of dopamine and norepinephrine, which are involved in attention, focus, and impulse control.
- Vitamin D: Helps regulate the production of neurotransmitters like dopamine and serotonin that help with focus, mood, and behavior control.
This doesn’t mean that diet alone causes ADHD or that it can cure ADHD. It’s a more complex condition with many factors at play. It is also important to remember that everyone’s needs are different and that by getting the right nutrition for our bodies and brains, we may be able to handle the condition more naturally.
Can Environmental Toxins Cause ADHD?
The environment we live in can play a significant role in the development of ADHD. Certain toxins and pollutants that we are exposed to, especially during pregnancy and early childhood, can increase the chances of developing ADHD.
One of the more obvious dangerous toxins is lead. If a pregnant woman is exposed to lead through old paint, contaminated water, or other sources, it can interfere with the baby’s brain development. This can increase the likelihood of the child later showing symptoms of ADHD like difficulty focusing, hyperactivity, and impulsivity.
Pesticides and air pollution are two other environmental toxins that can play a significant role in developing ADHD. Children exposed to higher levels of these substances have a much higher risk of being diagnosed with ADHD.
Thankfully, with more modern and environmentally friendly methods of farming and production now available, exposure to toxins like pesticides and lead is decreasing.
Debunking ADHD Myths
There are so many misconceptions about just what causes ADHD, and it’s time to debunk some of the more popular myths surrounding the condition and also what causes it.
Myth 1: ADHD is Caused by Bad Parenting
ADHD is not caused by “bad parenting.” Many people have the idea that if a child has ADHD, it must be because of the parents. But that’s not the case. ADHD is a neurodevelopmental condition, and while there are a few causes, it is not about how a child is raised and more about how the brain is wired.
Myth 2: ADHD is Caused by Excessive Screen Time
Another one of the more common myths is that ADHD is caused by too much time on screens and devices. Yes, too much screen time can cause behavior and focus issues, but it doesn’t cause ADHD itself. ADHD is rooted in brain development and neurotransmitter imbalances – not how much time you spend on your phone or tablet.
Myth 3: ADHD only Affects Lower Socioeconomic Classes
The idea that ADHD is caused by someone’s income level or social background is not only mind-boggling but also factually incorrect. ADHD affects people from all kinds of economic and social classes. While access to resources for diagnosis and treatment can vary, the condition itself is in no way tied to socioeconomic status and is a universal issue.
So, What Causes ADHD?
The bottom line is ADHD is a complex condition. It doesn’t come from just one single cause but rather a mix of the genetic environment and neurological factors all working together. From genetic predispositions to ADHD that run in the family or environmental influences during pregnancy and early childhood, this article has looked at just what the various factors are that contribute to the cause of ADHD.
Rather than getting caught up in finding a single cause, it is crucial to understand that ADHD is multifaceted, and understanding that is the first step in providing the best care and support. Approach ADHD with empathy, patience, and a willingness to find what works best for each person.
- Thapar, A., Cooper, M., Jefferies, R., & Stergiakouli, E. (2011). What causes attention deficit hyperactivity disorder? Archives of Disease in Childhood, 97(3), 260–265. https://adc.bmj.com/content/97/3/260
- Larsson, H., Chang, Z., D’Onofrio, B. M., & Lichtenstein, P. (2013). The heritability of clinically diagnosed attention deficit hyperactivity disorder across the lifespan. Psychological Medicine, 44(10), 2223–2229. https://www.cambridge.org/core/journals/psychological-medicine/article/abs/heritability-of-clinically-diagnosed-attention-deficit-hyperactivity-disorder-across-the-lifespan/F694F443AA07EE7C253D22FDB1DE540D
- NHS UK. (2021, December 24). Causes: Attention Deficit Hyperactivity Disorder (ADHD). https://www.nhs.uk/conditions/attention-deficit-hyperactivity-disorder-adhd/causes/
- National Institute of Mental Health (NIMH). (2024). Attention-Deficit/Hyperactivity Disorder.https://www.nimh.nih.gov/health/topics/attention-deficit-hyperactivity-disorder-adhd
Our Medical Affairs Team is a dedicated group of medical professionals with diverse and extensive clinical experience who actively contribute to the development of our content, products, and services. They meticulously evaluate and review all medical content before publication to ensure it is medically accurate and aligned with current discussions and research developments in mental health. For more information, visit our Editorial Policy.
MentalHealth.com is a health technology company guiding people towards self-understanding and connection. The platform provides reliable resources, accessible services, and nurturing communities. Its purpose is to educate, support, and empower people in their pursuit of well-being.

Michael Quinn is a writer with five years of experience unpacking everything from technology and politics to medicine and telecommunications.
Dr. Brittany Ferri, PhD, is a medical reviewer and subject matter expert in behavioral health, pediatrics, and telehealth.
Our Medical Affairs Team is a dedicated group of medical professionals with diverse and extensive clinical experience who actively contribute to the development of our content, products, and services. They meticulously evaluate and review all medical content before publication to ensure it is medically accurate and aligned with current discussions and research developments in mental health. For more information, visit our Editorial Policy.
MentalHealth.com is a health technology company guiding people towards self-understanding and connection. The platform provides reliable resources, accessible services, and nurturing communities. Its purpose is to educate, support, and empower people in their pursuit of well-being.