What is ADHD? Why do some develop it?
Updated: Apr 3
ADHD was first recognized as a behavior problem, but now we know it’s a developmental disorder. Don’t worry though. Having a developmental disorder doesn’t make you stupid or damaged. It simply means that brain development is a bit different. We’ll tackle details here.
Typical Brain Development
Our brains have billions of nerve cells called neurons that start developing a few weeks after conception. Within 6 months after conception, there are even more neurons than are found in an adult brain. As we develop, neurons grow and make connections with one another. The number of brain cells decrease as unneeded neurons are pruned away.
A network of fibers develops to connect the brain cells in order to interact with other parts of the brain and to perform complex functions. Neurotransmitters help send messages between nerve cells.
We’ll tackle neurotransmitters more in future posts. They’re important!
How long does it take for the brain to fully develop?
We might look pretty mature by our teen years, but our brain is still growing!
The first 3-4 years of life is a time of rapid brain development, but it continues for more than 20 years.
The prefrontal cortex is especially interesting. It helps us plan, organize, make decisions, and maintain self control. These are considered executive functions and are often problematic for those with ADHD.
The prefrontal cortex typically doesn’t finish full development until mid-20s. That means our brains are still developing key areas into our early adult years!
For a fun interactive way to see all areas of the brain, visit Brainfacts.org.
How does ADHD develop?
There are many things that affect our brain development that can lead to symptoms of ADHD.
At this point we don’t diagnose the cause of the ADHD since treatment is geared toward addressing the symptoms, but it can be helpful to know that there are many reasons a person develops ADHD.
Like many things, brain development is affected by our genetics. Genetics affects how we look, how tall we should grow, our intelligence, and risks of certain health problems – such as cancer or heart disease. Of course our genetics are only the blueprint. Our environment, nutrition, experiences, and much more also affect how we grow and develop.
If one parent has ADHD, a child is more likely to have ADHD. If both parents have ADHD, their child is much more likely to have ADHD.
While a baby is still in its mother’s womb, it is considered a fetus. This is considered the prenatal time of development.
Many things can affect development during the prenatal time. Drugs and alcohol, illness, and other stressors affecting the mother can affect the baby.
Prematurity (being born before the due date) and being small at birth can increase the risk of developmental disorders, including ADHD.
Illness, injury, toxins and more… oh, my!
The first few years of a child’s life can be complicated by illness, injury, nutritional deficiencies, and toxins. These can all affect brain development.
Even after the critical developmental years, injuries and toxins to the brain can change our brain function. Think of a teen or adult who has had a concussion. Their brain function can be severely altered. They might suffer from mental fogginess, fatigue, irritability, and more after the injury. In fact, sometimes people will be treated with medications commonly used for ADHD temporarily after a concussion.
What it’s NOT:
ADHD is not due to bad parenting, poor discipline, or bad schools.
Yes, those things can worsen a child’s behavior, but they don’t cause ADHD.
What about sugar?
ADHD also isn’t from too much sugar.
Studies have even shown that even when a parent perceives worsening of behavior after sugar, independent observers see no real change. For more on that and how diets affect ADHD, see Special Diets for ADHD.