You may have heard in the media that poor diet, food dyes, too much sugar, environmental chemicals, poor schooling, too much TV, poor pre-natal care or poor parenting are causes of ADHD.
It is possible that drug or alcohol use during pregnancy could alter the brain and may be a possible cause of ADHD. As for the other factors, while credible research has not been able to validate any of them as causes of ADHD, they definitely can exacerbate ADHD symptoms.
What we do think is that ADHD is a brain based biological disorder, caused by a number of factors that affect how the brain develops and functions. And the one factor that stands out is a neurotransmitter imbalance.
As you know, each region in the brain is responsible for a particular function; of course there are overlapping functions. But for the various regions to do their jobs, they must be linked to one another through neural circuits that carry information from one brain region to another.
For this to happen neurotransmitters must be available to transmit the messages. But, in the ADHD brain, because there an imbalance of dopamine and norepinephrine, the messages are not transmitted efficiently.
As a result, the various regions of the brain cannot perform their functions well, resulting in the ADHD symptoms you experience, such as difficulty:
- paying attention
- regulating emotions
- and more…
So, there you have it. I’m sure continuing research will uncover more in the coming years.
You read above that the primary cause of ADHD seems to be an imbalance in neurotransmitters in four primary areas in the brain — below are highlights of what is happening in these four regions of the ADHD brain.
The primary job of the frontal lobe is to carry out higher mental processes — thinking, decision making and planning. You know, the stuff that is hard for you.
Another job is to inhibit and keep the rest of the brain under control. In particular, the frontal lobe or logical brain is supposed to help keep our emotions in check — sometimes referred to as emotional regulation.
But, because of the imbalance of dopamine, the messages between the neurons in this region are not transmitted efficiently — and the frontal lobe cannot do its job efficiently.
The result is your ability to carry out various executive functions and regulate your emotions is compromised.
The Limbic System’s primary job is to regulate our emotions.
But, as a result of the imbalance of dopamine and norepinephrine in this region, you may experience emotional volatility. That is you may:
- be quick to get sad, angry or excited.
- feel you emotions more intensely — high highs and low lows.
An imbalance of dopamine and norepinephrine in this region can only contribute to your restlessness and inattention.
The basal ganglia, when functioning properly:
- helps you decide what to do next.
- inhibits you from trying to do a million things at once so you can attend to what you need to do.
- gives you the mental energy you need to get-up-and-go.
Because of a deficiency of dopamine, the basal ganglia is underactive and can result in you having a hard time deciding what to do in the moment.
So, you may end up:
- stuck in neutral thinking, “I could do this or this or…”
- flitting about from one tasks to another.
- having a hard time transitioning from one activity to another.
The RAS (reticular activating system) is a network of neurons and neural fibers, located in the brain stem, that connects with other parts of the brain. One of its primary functions is to sorted information from the outside and pass it along to the rest of the brain system to be processed and acted upon. It is the key to turning on our brain so we give attention to the most important information.
But, because of a deficiency norepinephrine, the RAS is not able to filter and process incoming information effectively.
As a result:
- all the stimuli, information, from the outside floods your mind.
- you are not able to focus your attention.
- you become overwhelmed.
- and you miss the important information!
So, you don’t see important email lost in the deluge of all the others in your inbox. You don’t hear your colleague trying to get your attention in a crowded convention room. You miss the final boarding call for your flight over the intercom at the airport.
There is just too many competing incoming stimuli.