The Causes of ADHD
Author:
Dr. Allan Schwartz, Ph.D.
Co-Author:
Michael Quinn
Editor:
Simone Paget
Reviewer:
Dr. Brittany Ferri, Ph.D.
Attention-deficit/hyperactivity disorder (ADHD) is a complex neurodevelopmental condition that affects millions of people worldwide. Its symptoms include difficulty focusing, impulsivity, and hyperactivity, stemming from genetic, environmental, and neurobiological factors.
ADHD often runs in families, suggesting a genetic component, while other factors include premature birth, exposure to toxins, and early brain injuries.
Is ADHD Genetic?
ADHD affects 1 to 3% of children globally. While this percentage may seem small, it represents millions of children when considered within the context of a global population of nearly 8 billion. This widespread impact underscores the importance of continued research into the causes and contributing factors of ADHD [1].
Research shows that ADHD often runs in families, with twin studies suggesting heritability rates of between 60% and 90%. Therefore, 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 is due to a specific gene that affects how the brain develops and functions, particularly in areas related to attention, impulse control, and emotion regulation [2].
Environmental and Developmental Influences on ADHD
While genetics significantly contributes to the development of ADHD, environmental and developmental factors also play a crucial role. These influences, particularly during pregnancy and early childhood, can affect brain development in ways that increase the risk of ADHD, especially when combined with genetic predispositions [3].
Prenatal Factors
Several conditions during pregnancy are associated with increased ADHD risk:
- Exposure to toxins such as lead, pesticides, and air pollutants can interfere with fetal brain development, particularly in areas involved in attention and impulse control [3].
- Substance use, including smoking, alcohol, or drugs during pregnancy, has been linked to neurodevelopmental disruptions.
- High maternal stress may affect fetal neurochemistry, contributing to later behavioral and cognitive challenges.
- Poor prenatal nutrition, especially deficiencies in omega-3 fatty acids and folic acid, may impair healthy brain development.
- Birth complications, including premature delivery or low birth weight, can lead to structural and functional brain changes that increase susceptibility to ADHD.
Early Childhood Factors
The early years of life are critical for brain development, and negative experiences during this time can impact cognitive and behavioral functioning [3]:
- Emotional or physical trauma, including neglect and abuse, can alter brain structure and affect attention and self-regulation.
- Chronic stress in the home environment may disrupt the development of neural pathways essential for executive functioning.
- Ongoing exposure to toxins, such as secondhand smoke or polluted air, can impair attention and impulse control.
- Infections and head injuries during early childhood have also been associated with ADHD-like symptoms.
Additional Considerations
Other factors that may elevate ADHD risk include:
- Traumatic Brain Injury (TBI), particularly in areas of the brain associated with executive function.
- Advanced maternal age has been linked in some studies to a modest increase in ADHD risk, though the mechanisms remain unclear.
ADHD rarely stems from a single cause. Instead, it reflects a complex interplay of genetic, environmental, and developmental influences. Understanding these connections can guide early intervention, reduce risk, and support more personalized care strategies.
The Neurobiological Causes of ADHD
While genetics and environmental factors, especially during formative years, contribute to the development of ADHD, many researchers have found that the brain chemical dopamine also plays a role in ADHD. 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 [4].
The brains of people with ADHD are slightly different in structure and function. Studies show that the prefrontal cortex, the part of the brain responsible for focus, decision-making, and self-control, is smaller and less active in people with ADHD. Furthermore, communication pathways in the ADHD brain may not function as smoothly, making it challenging to switch between tasks and ignore distractions that may arise [5].
These structural differences in the brain help explain why people with ADHD struggle to stay organized and on track with tasks. However, it’s essential to recognize that ADHD does not reflect a deficiency; it simply represents a different way the brain functions for some individuals.
How Diet and Nutrition Affect ADHD
In addition to genetic, environmental, and neurobiological influences, diet and nutrition may also 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 [3].
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.
Diet alone does not cause ADHD, nor can it cure the condition. ADHD is a multifaceted neurodevelopmental disorder influenced by genetics, brain function, and environmental factors. However, nutrition can play a supportive role in managing symptoms. Dietary choices help improve focus, energy levels, and overall brain function.
It’s also important to recognize that nutritional needs vary from person to person. While a balanced diet may not replace other forms of treatment, it can be a valuable part of a holistic approach to ADHD care. Prioritizing good nutrition may help individuals better manage their symptoms and support overall well-being.
Debunking ADHD Myths
Despite there being a lot of known potential causes of ADHD, whether it’s genetic, environmental, or nutritional, there are still many misconceptions surrounding the origins of the disorder. Here are some of the more popular myths surrounding the condition and what causes it:
Myth 1: Bad Parenting Causes ADHD
Parenting doesn’t cause ADHD. Although some people mistakenly believe that a child’s behavior reflects poor discipline or parenting failures, this assumption is inaccurate and harmful. ADHD is a neurodevelopmental disorder rooted in differences in how the brain functions and processes information. Brain structure, neurotransmitter activity, and genetics play a far more significant role in the development of ADHD than parenting style. While supportive and consistent parenting can help manage symptoms, it does not cause or prevent them.
Myth 2: Excessive Screen Time Causes ADHD
Excessive screen time may contribute to difficulties with behavior and attention, but it is not a direct cause of ADHD. The condition is rooted in neurodevelopmental differences, including how the brain matures and the function of neurotransmitters. Although managing screen use is vital for overall mental well-being, ADHD develops independently of screen habits, and genetics, brain chemistry, and early developmental factors are primary influences.
Myth 3: ADHD Only Affects Lower Socioeconomic Classes
ADHD affects individuals from all socioeconomic backgrounds. It is not caused by income level or social status but is linked to how the brain develops and functions. Although people from lower-income households or challenging family situations may face more obstacles in getting diagnosed or treated, these factors do not cause ADHD itself.
That said, difficult life circumstances, such as poverty, family stress, or abuse, can add to the challenges children face. These situations are often linked to higher rates of mental health issues, including ADHD. Still, the condition remains a neurological one that can affect anyone, regardless of background [3].
What Influences the Development of ADHD
ADHD is a complex neurodevelopmental condition influenced by multiple factors rather than a single cause. Genetics plays a significant role, especially when there is a family history of ADHD. Environmental influences during pregnancy and early childhood, such as exposure to toxins or premature birth, also contribute to the condition’s development. Neurological differences, including how the brain processes information and regulates attention, further shape ADHD.
Understanding that ADHD arises from this combination of influences is key to offering practical support. Rather than pinpointing one cause, it’s more helpful to take a compassionate and individualized approach to care, tailored to each person’s unique needs.
- 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. Accessed May 29 2025.
- 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. Accessed May 29 2025.
- Thapar, A., Cooper, M., Eyre, O., & Langley, K. (2013). Practitioner review: What have we learnt about the causes of ADHD? Journal of Child Psychology and Psychiatry, 54(1), 3–16. https://doi.org/10.1111/j.1469-7610.2012.02611.x. Accessed May 29 2025.
- Blum, K., Chen, A. L.-C., Braverman, E. R., Comings, D. E., Chen, T. J. H., et al. (2008). Attention-deficit-hyperactivity disorder and reward deficiency syndrome. Neuropsychiatric Disease and Treatment, 4(5), 893–917. https://doi.org/10.2147/NDT.S2627. Accessed May 29 2025.
- Arnsten, A. F. T. (2009). The emerging neurobiology of attention deficit hyperactivity disorder: The key role of the prefrontal association cortex. The Journal of Pediatrics, 154(5), I–S43. https://doi.org/10.1016/j.jpeds.2009.01.018. Accessed May 29 2025.
The Clinical Affairs Team at MentalHealth.com is a dedicated group of medical professionals with diverse and extensive clinical experience. They actively contribute to the development of content, products, and services, and meticulously review all medical material before publication to ensure accuracy and alignment with current research and conversations in mental health. For more information, please visit the 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.
Dr. Allan Schwartz is a medical writer with over 30 years of clinical experience as a Licensed Clinical Social Worker. He writes about various mental health disorders, eating disorders, and issues related to relationships, stress, trauma, and abuse.
Dr. Brittany Ferri, PhD, is a medical reviewer and subject matter expert in behavioral health, pediatrics, and telehealth.
Medical Reviewer:
The Clinical Affairs Team at MentalHealth.com is a dedicated group of medical professionals with diverse and extensive clinical experience. They actively contribute to the development of content, products, and services, and meticulously review all medical material before publication to ensure accuracy and alignment with current research and conversations in mental health. For more information, please visit the 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.