When you first receive an autism or ADHD diagnosis, it is normal to have a lot of questions. One of the most common questions we receive is whether the conditions are genetic or not. If you ask Google, you’ll find a flood of conflicting information. Some suggest genes are responsible, and others point to environmental, lifestyle, or early experiences. The reality is, it is more nuanced and more interesting.
Decades of research show that both autism and ADHD have strong genetic foundations. However, genetics alone do not determine how a person’s brain develops, how traits present, or what support they may need across their lifetime.
In this month’s blog, we look into this common, somewhat-complicated question and how evidence-based insight can help replace outdated myths so we can understand each person’s unique brain in a way that promotes wellbeing, regulation, and function.
What genetics really tell us about autism and ADHD
When autism or ADHD is described as genetic, it does not mean there is a single gene responsible. Instead, many genes contribute to how the brain develops, communicates and regulates itself.
ADHD has one of the highest heritability estimates of any neurodevelopmental condition, commonly cited at around 70 to 80 percent. Autism also shows strong genetic influence, with research demonstrating higher rates among siblings and close family members. [1]
These findings explain why neurodivergent traits often appear across generations. They do not mean that genetics determines a diagnosis. We know genes influence brain wiring, not outcomes, abilities, or quality of life.
Likewise, we cannot point solely to genetics as the trigger for autism or ADHD, which is why it is important to speak to a medical professional for support with diagnosis and understanding the conditions.
Is autism hereditary or genetic?
Autism is considered a neurodevelopmental difference that can be influenced by genetics and is a variation in how a human brain develops and functions.
Genetic influence does not mean autism is caused by parenting, lifestyle choices, or a single inherited gene. What it can be interpreted to mean is that certain genetic patterns can shape how the brain processes communication, sensory input, and social information.
People with autism may experience challenges in environments that are not designed for neurodivergent brains, but they may also demonstrate strengths such as deep focus, creativity, pattern recognition, and unique perspectives.
Is ADHD genetic or environmental?
ADHD is shaped by both genetics and environment. Genetics influences how brain networks involved in attention, impulse control, and emotional regulation develop. Environmental factors then interact with this genetic foundation over time. These may include sleep patterns, stress, learning demands, sensory load, and nervous system regulation.
The environment does not cause ADHD. Rather, it can influence how strongly traits are expressed and how supported an individual feels in daily life. This helps explain why ADHD can look different across individuals and why support needs may change as children grow.
What about genetic testing?
There is currently no genetic test that can diagnose autism or ADHD.
While genetic testing can be helpful in identifying some rare medical or developmental conditions, autism and ADHD are understood through a broader lens. Assessment focuses on developmental history, behaviour, strengths, challenges and how the brain responds to everyday demands.
This whole-person approach recognises that neurodevelopment is complex and individual.
A neuro-affirming approach at Neurofit Brain Centre
At Neurofit, autism and ADHD are recognised as natural variations in brain development, not conditions to be fixed or cured. Every individual has a unique neurological profile shaped by genetics, environment and experience.
Rather than focusing solely on labels, Neurofit takes a brain-based approach that looks at how each person’s nervous system functions in real life. Therapy is personalised to support regulation, attention, emotional resilience and cognitive performance in ways that respect your individuality.
This approach values your strengths; supports any challenges you may have, and focuses on helping you function more comfortably and confidently in your everyday life.
Focusing on support, not causes
Autism and ADHD are strongly influenced by genetics, but they are not defined by genes alone. Brain development is dynamic and responsive to support and environment.
For families and individuals, the most meaningful question is not where neurodivergence comes from, but how to best support each unique brain. With the right, personalised support, neurodivergent individuals can thrive in ways that align with who they are.
Our team at Neurofit Brain Centre can help you with this journey.
Contact our friendly team today to find out more.
Disclaimer
All information is general and not intended as a substitute for professional advice. Neurofit Brain Centre can consult with you regarding your individual health needs.
References
[1] Faraone, S. V. and Larsson, H. (2019). Genetics of attention deficit hyperactivity disorder. Molecular Psychiatry, accessed online 17 January 2025, https://pubmed.ncbi.nlm.nih.gov/29892054/
