“Normal” brain vs ADHD brain. What’s different and why.

Yes, kids will be kids. They can be impulsive or over active. And yes, lots of kids have trouble paying attention and doing things they do not want to do. And no, not all kids have ADHD.

But, there are kids who truly do have ADHD. And it is not that they are lazy or unmotivated or parented poorly. Pulling up their socks is not going to help.

Kids with ADHD want to do good. But their brain makes it hard to.

ADHD is real: Kids with ADHD have different brains than people without ADHD. It is critical to understand ADHD so that kids’ behaviours are not misconstrued as normal (or worse: bad, lazy, unmotivated, or manipulative). Understanding their neurological differences is also important so these kids get the proper support they need. So, when kids get in trouble, we can remember their brain is not set up to help them avoid that trouble. A lot of the time, they really can’t help it. They need our help. 

The brain is the most complex organ in our body so understanding the brain can be tricky. However, in this article, my goal is to simplify the research as much as I can to help you understand what is happening in the ADHD brain and what that might mean for your child.

ADHD slows brain development

The brain develops the same way in the ADHD brain. However, brain development is slower, especially in the front parts that help control attention and impulsivity. Thus, ADHD is considered a neurodevelopmental disorder.

Over time, the ADHD brain does mature. However, depending on severity of symptoms, the brain might not reach the same level of maturity as the non-ADHD brain. Indeed, neuroscientists found that adults who were diagnosed with ADHD as children had a lower total brain volume than adults who were not diagnosed with ADHD. The cortical thickness of the outer layer of their brain was lower and they had more cortical thinning in the parts of the brain affected by ADHD.

Essentially, this means that these adults had fewer brain cells in these areas. A reason why may be because the non-ADHD brain develops brain cells faster than the ADHD brain. Thus, those individuals have more grey matter to start with in the first place before cortical thinning starts to happen.

Structural, Functional, and Chemical Differences

Overall, there are differences in the structure, function, and chemistry of the ADHD brain compared to the non-ADHD brain.

Structural Differences

Researchers at Radboud University Nijmegen Medical Centre conducted the largest review ever, scanning more than 3200 ADHD brains. They found that the overall size of the ADHD brain is smaller than the non-ADHD brain and the brain volume in key areas of the brain are smaller as well.

Although the size differences are small (about 4%), they are significant because the parts of the brain that are affected impair kids’ day-to-day lives and can result in problems like poor impulse control, emotional reactivity, limited delayed gratification, hyperactivity, distractibility, poor planning, forgetting to do things, and disorganization. Learning is also affected. (Fortunately, brain size does not affect intelligence – in fact, a lot of kids with ADHD have high levels of intelligence.)

As I already mentioned, there is less grey matter (brain cells) in the outer layer of the ADHD brain, which is important for processing information and helping kids think before they act. There are also abnormalities in the structure of white matter (nerve fibers), which cuts off communication between different parts of the brain and can make it hard for kids to, for example, remember the steps they need to do as they finish a task or remember they have to finish their work before they can go to their friend’s house.

Below is an overview of the key parts of the brain that are structurally affected in the ADHD brain.

Striatum. This is the brain’s reward system and assistant to the brain’s CEO. Dopamine is processed here, which helps control motivation, reward, and pleasure. It also helps process our thoughts, feelings, and experiences.

When working effectively, the striatum sends one piece of important information to the cortex to think about at a time. In the ADHD brain however, the striatum sends several different random pieces of information to the cortex at a time, which makes it really hard for kids to focus.

Three specific parts of the striatum are effected:

  • Caudate nucleus: Stores and processes memories and is important for learning. It helps kids decide how they should behave to achieve certain outcomes, which is hard for kids with ADHD. An example is thinking about doing homework now so a) it is done, b) my parents trust me to be responsible, and c) I can go to the party this weekend. Kids with ADHD tend to forget the reasons why they would do something and end up choosing to do the most interesting thing in the moment, such as play video games instead of homework. Or, you know, pick plaster from the walls (or whatever else it is kids do in their rooms) instead of getting dressed in the morning.
  • Putamen: A big part of the brain that helps with movement and contributes to impulsive behaviours. 
  • Nucleus accumbens: Important for reward processing and motivation. Effort is affected because this part of the brain plays an important role between motivation and action. Thus, if an action/task is not rewarding for kids with ADHD, like homework, it likely isn’t going to happen without a lot of nagging (and then kids are motivated to have the nagging stop, which is why they finally do it. So now we are reinforcing them to do whatever it takes to stop the nagging vs. doing the thing we want them to do in the first place).
My beautiful drawing of the brain.

Amygdala. The amygdala has a major role in motivation, processing emotions, and controlling emotional behaviour. Although smaller in the ADHD brain (particularly the left side), it is overactive and does not communicate well with the prefrontal cortex. Thus, it is hard for kids with ADHD to process (and cope with) emotions. They can become easily overwhelmed with emotions, taking up all their brain power and leaving little resources to stay cool and think about their actions. This is why so many kids with ADHD have trouble managing frustration, waiting patiently, keeping their cool, and avoiding big overboard reactions.

The amygdala is also important for perceiving different emotions, such as fear and sadness, as well as controlling aggression. Thus, many kids with ADHD have ahard time processing others’ emotions, which can lead to social conflict problems.

Hippocampus. The hippocampus is mostly connected to long-term memory but is also important for learning, motivation, and emotions. It plays a role in helping stop automatic (emotional) reactions to things and leads to problems with hyperactivity.

Functional Differences

The ADHD brain also works differently than the non-ADHD brain. In particular, there is less blood flow to the parts of the brain responsible for executive functions, or the CEO of the brain. Less blood flow means that those parts of the brain are underactive, which is why kids with ADHD have a hard time with maintaining attention, controlling their behaviours, and managing upset than kids without ADHD.

Conversely, there is increased blood flow to certain parts of the brain that helps with keeping focus. This means that these parts of the brain are overactive in the ADHD brain and makes it hard for kids to sustain their attention and avoid distraction. 

Chemical Differences  

Finally, there are chemical differences in the ADHD brain, which affects the activity and communication between different parts and networks of the brain. The chemicals are known as neurotransmitters, which are essentially chemical messengers that move messages from one brain cell to the next. In the ADHD brain, the messages are not passed effectively between neurons.

Dopamine is a major neurotransmitter that does not work efficiently in the ADHD brain. Essentially, there are too many dopamine transporters in the brain with not enough receptors. This means that dopamine moves too quickly for the messages in the brain to be picked up and therefore are unable to send important messages on. (I imagine it a little like millions of messages in bottles thrown into the ocean and only one or two actually being found and read. And the lucky messages found are likely not at all relevant or important.)

Dopamine is important because it helps control the brain’s reward and pleasure centre and is essential for sustaining attention and staying motivated. Dopamine helps kids predict how rewarding a task will be. If kids think something is going to be fun or worth their while, dopamine runs high and kids will likely get started on the task right away.

The ADHD brain makes it hard
to get started on boring things.

Because dopamine does not work efficiently in the ADHD brain, routine tasks with little reward are definitely not interesting. Thus, it is hard for kids to get started on, or stick with things without getting distracted by something more interesting. This is why so many kids lose interest in things fast and bounce from one thing to the next.

Inefficient dopamine systems also make it hard for kids to wait for things they want. Or doing something now (e.g., homework) for a later reward (e.g., having a sleepover on the weekend). They have a hard time anticipating (future) pleasure and so constantly seek pleasurable experiences now. Things essentially need to GRAB kids’ attention for them to focus.

Dopamine is also important for learning. If kids do something that increases their dopamine in the brain, their brain actually changes so that kids are more likely to engage in that same behaviour again in the future. So, if kids get a rush from doing a really dangerous trick on their bikes, or laughs from classmates from being silly, they will likely do it again, even if we tell them not to. (PS Video games increase dopamine levels and trigger the pleasure centre of the brain, thus creating a craving.)

Click here to read a short overview about the specific parts of the brain dopamine effects.

In sum

The ADHD brain is smaller than the non-ADHD brain and has fewer connections between different brain regions. Their brains do not have the neural organization to self-regulate and to stop automatic responses. In other words, their brain is built to respond impulsively to their environment and makes it hard for them to do the things they need to do day in and day out.

What can I do?

It is clear that kids with ADHD need our help. The best support is a multi-modal approach in which they receive a variety of interventions. We know that a combination of medications and behaviour therapy are the most effective approaches to managing ADHD.

ADHD affects the brain. Thus, medications are often part of treatment plans because they can improve the efficiency of dopamine and normalize the connections in the motivation and reward networks of the brain, even when kids are doing boring tasks. Medications can protect and promote brain development and help kids with ADHD pay attention better, think about the consequences of their actions, and keep their cool.

With regards to behaviour strategies, focused intervention on developing the executive skills of the brain is important. Structuring the environment and providing the necessary supports for areas of difficulty, such as using pictures to help support the working memory, are also helpful.

To maximize support for your child and optimize your child’s treatment plan, it is important to have your team of professionals to support you and your child on your journey to success. 

Before anything, your relationship with your child is most important. Practice patience. The next time your child does something disruptive, think about how you can help support the still-developing brain. Your brain is (hopefully) fully developed, so you need to be your child’s frontal lobe surrogate until they develop the skills to do things with more success independently.

Finally, highlight your child’s interests, efforts, and accomplishments – their strengths are the foundation from which success is built from. When kids feel confident and are interested, their brain can work much like others without ADHD.

Additional Resources

If you are looking for things to read, here are some book suggestions to learn more about ADHD.

  • Taking Charge of ADHD, Third Edition: The Complete, Authoritative Guide for Parents (Russell Barkley)
  • Driven to Distraction: Recognizing and Coping with Attention Deficit Disorder from Childhood to Adulthood (Edward M. Hallowell & John J. Ratey)
  • Delivered from Distraction (Edward M. Hallowell & John J. Ratey)
  • Adolescents and ADD: Gaining the Advantage (Patricia Quinn)
  • My Brain Needs Glasses: Living with Hyperactivity (Annick Vincent)
  • Survival Guide for College Students with ADHD or LD (Kathleen Nadeau)
  • The Explosive Child (Ross Greene)


Sign up below for the weekly SuperParent newsletter.

Receive a FREE copy of "How To Talk To Your Kids About ADHD".

Delivered Weekly • 100% Spam Free • Unsubscribe Anytime.

1 thought on ““Normal” brain vs ADHD brain. What’s different and why.”

Leave a Comment

Show Buttons
Hide Buttons