What Causes ADHD?
Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental condition that affects both children and adults. It’s often associated with difficulties in attention, impulsivity, and hyperactivity, though not everyone experiences all of these in the same way.
Understanding what causes ADHD can help reduce stigma and support early recognition. While there's no single cause, research points to a number of factors that may contribute to the development of ADHD.
1. Genetics and Family History
One of the strongest known causes of ADHD is genetics. ADHD tends to run in families. If a parent or sibling has ADHD, there’s a higher chance someone else in the family may also be affected.
- Studies show that ADHD is highly heritable
- Certain genes linked to the brain’s dopamine system (which affects attention and impulse control) may play a role
- Inherited traits can influence how the brain processes information and regulates behaviour
2. Brain Structure and Function
Brain imaging studies suggest that people with ADHD may have differences in certain areas of the brain, particularly those linked to attention, decision-making, and impulse control.
These differences include:
- Delayed brain development in some regions
- Differences in how brain chemicals like dopamine and noradrenaline work
- Reduced activity in parts of the brain that help with planning and focus
This isn’t a sign of damage or “wrongness” - just a different way the brain is wired.
3. Pregnancy and Early Development Factors
Some prenatal or early life factors have been linked to an increased risk of developing ADHD, such as:
- Being born prematurely (before 37 weeks)
- Low birth weight
- Exposure to alcohol, tobacco, or certain drugs during pregnancy
- Complications at birth, such as lack of oxygen
These factors are believed to influence brain development, especially during critical stages.
4. Environmental Influences
While environment alone doesn’t cause ADHD, certain environmental factors may increase the likelihood of symptoms in children who are already more vulnerable.
These may include:
- Long-term exposure to lead or other toxins
- High levels of family stress or conflict
- Lack of access to stable routines or sleep
- Poor diet or inconsistent eating habits (though not direct causes, they may affect behaviour)
It’s important to note that poor parenting, sugar, or watching too much TV do not cause ADHD, though they can sometimes affect how symptoms show up or are managed.
5. Other Factors and Co-occurring Conditions
ADHD can sometimes appear alongside other conditions, such as:
- Autism spectrum condition (ASC)
- Anxiety disorders
- Learning difficulties (like dyslexia or dyspraxia)
- Depression or sleep problems
These co-existing challenges don’t cause ADHD, but they may complicate how it is diagnosed or understood.
Summary: What We Know So Far
ADHD is a complex condition with multiple causes, often involving a mix of genetic, brain-based, and environmental factors. No single cause explains every case, and no two people with ADHD are exactly alike.
What’s most important is recognising the signs early, getting the right support, and understanding that ADHD is not a result of laziness, bad behaviour, or poor parenting.