Written by Dr. Inez Van Roy on
September 14, 2021
Written by Dr. Inez Van Roy on:

Medically Reviewed by our Medical Affairs Team

What happens in my ADHD brain? 

Your brain development seems a little different with attention deficit hyperactivity disorder. While your brain might come with some frustrations sometimes, it also bears gifts that neurotypical people don’t have. If you don’t have ADHD, it might still be useful information.

The National Institute of Mental Health shows that ADHD is one of the most common childhood disorders. Adults and adolescents keep suffering from this disorder too.

In this article, you can read more about how these symptoms of ADHD translate to different brain development and brain structure. Also, you can learn which treatments are available for a patient with attention deficit hyperactivity disorder.

The neuroscience of your brain development with ADHD

 Adults and children with ADHD are usually described as having difficulty with 

  • impulse control, 
  • paying attention 
  • and hyperactivity.

Even the diagnosis “attention deficit hyperactivity disorder” refers to these ADHD symptoms. They complain about being easily distracted and bad planners (part of executive functions).

Well, these symptoms can be found in the brain. Children (and adults) differ in brain chemistry, brain structure, and in the brain networks.  

The brain of someone with ADHD compared to someone without it can be best understood by dividing it in parts. These all have their functions.

They are also interconnected through multiple brain networks and brain chemicals. One neuron releases these brain chemicals or neurotransmitters to get the messages across to the other neuron. Our brain can be divided in many ways, for the sake of this article let’s stick to the following division:

  • Forebrain
  • Midbrain
  • Hindbrain 

The prefrontal cortex

The brain of a child (and young adults) grows from the hindbrain towards the forebrain. As children age, they start to need and experience more functions of the forebrain (or the frontal lobe).  

Families start to notice that their school-age children have a difference in executive function and behavior. Usually, they suspect learning disabilities as a cause.

Attention deficit hyperactivity disorder was also recognized as one of the learning disabilities. Today we don’t recognize ADHD as such anymore. Research shows that people with ADHD still suffer as young adults. ADHD is not only for children.

The (pre)frontal cortex, situated in the forebrain (or the forehead area) is mostly responsible for your executive function. That is why we discuss this area first. Researchers believe its main function is:

  • executive function like
    • organization
    • problem-solving
    • planning
  • decision making
  • attention 
  • delayed gratification
  • impulse control
  • and so on.

These functions seem very much in line with ADHD symptoms. People with attention deficit hyperactivity disorder face these every day.

An example of how this might look in your day-to-day life is performing a speech or writing a thesis. You might find it difficult to find structure in your speech or article.

You might need a lot of time to get to the point. And, even when you get to the point you might miss the fact that your public does not understand the jargon.

It would only be logical that your brain is different from a neurotypical in this area as you don’t function the same way. Research confirms an impairment inactivity, characterized by a reduced blood flow.

Another difference with attention deficit hyperactivity disorder brains is in the way they might grow. Every brain grows from the back (the cerebellum) towards the front (the prefrontal cortex). Research shows that children with ADHD might need a few years more to mature this frontal area completely. 

The limbic system

Another area that we could consider as part of our forebrain is the limbic system. 

The limbic system is the heart of our emotions. This interesting and somehow primitive system handles regulating our emotions. 

It works together with many other systems by interpreting information at a lightning speed. Emotions are the first communicators that tell us how to survive in this complex world. They send us fear, sadness, happiness, or a boost of gratification. 

Our memory base is a part of this deeper and more central part of our brain. 

Imagine burning your hand as a kid while placing it on a hot stove. If all goes well, you will feel pain and instantly retract your hand from this damaging situation. The limbic system will surely do its job next time when seeing a stove. It activates this painful memory and might induce fear to prevent you from making the same mistake. 

You might not recognize your symptoms directly. Still, I would kindly remind you of the times you might have been described as impulsive, or fearless.

Your mother might have prayed for you when she saw you driving a bike or a car. It is not that she doesn’t trust you. Maybe she knows you are rather impulsive which might lead to accidents and interpreting situations as not so dangerous.

Research confirms that on a structural level people with ADHD have a different limbic system, for example: 

  • their amygdala (center of our anxiety so to say) 
  • and their hippocampus (center of memories) 

seems to be significantly smaller. Further, there might be signs of an impaired activity in this area.

The basal ganglia 

The basal ganglia is a combination of many structures, situated where the forebrain evolves into the midbrain. In the basal ganglia we can recognize:

  • the striatum
  • The globus pallidus
  • The ventral pallidum 
  • The substantia nigra
  • And the subthalamic nucleus. 

The location of these areas already suggests it. These structures are important for communication and information exchange within brain areas. It is also essential in dopamine production. Functions associated with the basal ganglia are 

  • (eye) movements, 
  • a role in motivation, 
  • decision making, 
  • and working memory. 

The research found volumetric abnormalities in these areas for children with ADHD. There might also be a difference in activation between adults with ADHD and adults without ADHD. 

Look at the functions that the basal ganglia support. It would be logical to see a difference between how the ADHD and the neurotypical brain works.

Reticular activating system 

The reticular activating system is a network of neurons throughout the brainstem and the medulla. This makes it part of our midbrain and hindbrain. The reticular formation could be understood as our relay system in the brain. 

This relay network plays a role in vigilance, arousal, and wakefulness. It is pretty difficult to conform to standards of the majority when your relay system is not working well. 

In ADHD this could translate as difficulty with modulating attention. Or it could look like troubles with filtering interfering stimuli. What starts with cleaning the dishes, ends up with reorganizing your junk drawer. You can blame your reticular activating system for these situations.

There are other signs that the brain of someone with ADHD is a bit different. Researchers don’t only find slower growth and smaller structures as mentioned above. Children with ADHD might also have a smaller brain volume.

Why do you experience these ADHD symptoms only sometimes?  

You actually can concentrate on plenty of things. You have a very capable neurodivergent brain. You might notice that you only experience these symptoms of ADHD in some situations. You certainly don’t experience this when it is a passion project or a hobby. 

Contrary to popular belief of your parents, or boss, you can feel a flow with total focus in those aspects of life. You are able to forget about time and space when you are deep into that special interest. 

Why is that? Well, this makes total sense. The ADHD reward or motivation system works differently than that of someone without ADHD. Interesting things will activate your reward or motivation system easier. They might get less interesting quicker. 

How do stimulant medications balance this in your ADHD brain?

Stimulants play on this system by balancing the chemicals. Our brain chemicals are very important. They help us activate these great cognitive functions like focus and motivation.

The first step is to spread the information through the brain. You need to force the nerve cells (or neurons) to take “action” to transfer the message throughout the networks. The chemicals that make them obtain this action potential are called neurotransmitters. 

Dopamine and noradrenaline are two neurotransmitters that seem to play a different game with people with ADHD. These two are deeply associated with the reward/ motivation system. Communication between two neurons is dependent on neurotransmitters (keys) and their receptors (locks). 

Imagine the area between cells as a space where a set amount of keys needs the correct amount of locks and time to connect. There are three things that can go wrong 

  1. not enough locks for all the keys, 
  2. not enough keys for all the locks and 
  3. inefficient contact. 

That seems to be what happens here. Medications to treat ADHD show positive results by working on these possible issues. Stimulant medications, for example, work by increasing the amount of dopamine and the time that it has to connect. 

In short, your symptoms are very real, and you can’t help it. Your sensitivity to reward and punishment differs on a structural and chemical level. This surely explains part of the symptoms of ADHD.

So, can brain scans provide an ADHD diagnosis?

This is a great question taking in account the above information. Research shows differences in brain structures, chemicals and the brain networks. Brain scans could theoretically show the road to this ADHD diagnosis. 

The problem with this is that not only people with ADHD show differences in these brain structures. We could misdiagnose other mental disorders as attention deficit hyperactivity disorder. Also the differences are not big enough to use as a diagnostic criteria.

So how to diagnose attention deficit hyperactivity disorder?

Only a doctor or psychiatrist can provide medical advice. To diagnose ADHD or any other mental health issue they follow the guidelines of the american psychiatric association. They have written the diagnostic criteria and are tested as followed.

The first step to diagnose ADHD is to conduct interviews as a way to gather information. Your therapist would like to evaluate in which situations you feel this way and when these symptoms have the biggest impact on your life. 

To sketch a complete view of what is bothering you and in which situations it is most common they might have a chat with the people around you. If you are a student, that might be asking your teacher what signs they have noticed. They might ask for concrete examples as well. 

Also, they might also talk to other familiar people closer to you, like your parents or your partner as an adult. Your parents or partner will surely notice certain signs like forgetfulness or impulsivity. 

The DSM-5 (or diagnostic and statistical manual) defines that you should show symptoms for more than 6 months. Further, ADHD is usually first noticed in childhood. That is why certain questions will be focused on current and past occurrences of these symptoms of ADHD.

The provider might ask about your childhood and upbringing to sketch a full picture. Basically, they want to get to know you on a deeper level. 

A qualitative interview can show how your subjective interpretation of these situations is. This is a great sign that you are in touch with feeling like something seems off.

Still, the mental health provider might also ask to bring a journal, homework or your tests. These are objective examples of your functioning.

Lastly, they might also go over the symptom checklist and some neuropsychological material.

These neuropsychological tests give insight into which brain functions are underperforming. They could also show no underperformance, but a big difference within your own other functions. This difference might explain your ADHD symptoms. 

Lastly, a doctor might do a physical exam to exclude any other diagnoses. The symptoms of ADHD might actually be caused by a medical problem or a differential diagnosis, for example: 

Your doctor or mental health specialist will give you the ADHD diagnosis and treatment. This is based on your inattention, hyperactivity and the other described patterns. As a treatment they might prescribe stimulant medication in combination with behavioral therapy. 

Conclusion

There is a difference between the ADHD brain and the neurotypical brain. We notice differences in the structure of the brain with ADHD. Some parts seem smaller and grow slower. Researchers find a different activation pattern in the brain with ADHD. There is reduced blood flow to areas. 

And lastly, the connectivity of networks between brain areas is different. This is due to how the neurotransmitters get distributed and used. Stimulant medication can balance the chemicals in your brain. These differences can’t be used to diagnose ADHD through a brain scan. 

Using your skills and interests in an optimal way can help you get in the flow. It is shown that children and adults with ADHD can achieve focus in these moments.

Lastly, a patient with ADHD will show symptoms of inattention, planning, and impulsivity. ADHD requires treatment, possibly in the form of stimulants. Other resources like planners, apps, and educational support are available to manage this. 

This article is for educational purposes. If your symptoms of inattention and impulsivity are hindering your life, you should contact a professional. They can provide more understanding about your behavior and treatment of this disorder.

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