Thinking Different: How ADHD Affects the Brain
ADHD is a neurodevelopmental condition, which means it affects how the brain develops. In turn, these changes to brain development affect the ways the brain functions throughout childhood and into adulthood.
Specifically, ADHD is known to impact the ability to perform executive functions, which includes the ability to organize, plan, and complete tasks. It also includes the ability to maintain attention and focus, and to regulate emotions and impulses.
Although many of the exact mechanisms behind the causes and development of ADHD are still unknown, research has found some changes in the brain in people with ADHD, which might explain why and how the condition affects thoughts and behavior.
In this post, we’ll explain some of those changes and how they may be linked to some of the symptoms we know to be part of ADHD.
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Atypical levels of dopamine
Dopamine is a chemical that acts as a messenger between cells in the brain. The transmission of these chemical messages within the brain allows us to interpret information from our environment and respond accordingly.
It’s involved in regulating motivation and controlling behavior, and it’s also important for learning and memory. Dopamine is released in the brain when we’re doing something that makes us happy, which helps us subconsciously learn what brings us joy. Dopamine can also be released in anticipation of these ‘rewards’, and so we get joy from working towards our long-term goals as a result.
In ADHD, levels of dopamine may be lower than usual, which makes it harder to maintain motivation to work towards long-term goals – because there may not be the same anticipatory sense of pleasure towards a future event.
When people with ADHD do experience a joyful or rewarding event, they still get an immediate release of dopamine, but the brain removes the chemical more quickly than usual, leading to a fast drop in motivation.
These changes to dopamine levels in the brain may help explain why people with ADHD find it harder to maintain attention and focus for a long period of time, particularly on tasks that don’t have an immediate reward. This also highlights why people with ADHD might chase that dopamine ‘high’ by participating in activities like playing video games, frequent social media or internet use, or impulse shopping.
This theory is further supported by the successful regulation of some ADHD symptoms through treatment with stimulant medications, exercise, and good sleep, which balance altered levels of dopamine in the brain.
Structural changes to the brain
Brain imaging scans suggest that people with ADHD may have a smaller frontal cortex than people without ADHD. The frontal cortex is a part of the brain that is involved in controlling planning, attention, and hyperactivity. Atypical structure of the frontal cortex may suggest changes to the ability to regulate these functions in people with ADHD.
It is also suggested that some of the bumps that form the classic folds of the brain, known as gyri, may also be structurally different in people with ADHD. Some of the impacted gyri are responsible for decision-making, movement, and executive function, behaviors which are affected in ADHD.
Altered activation of certain parts of the brain
There is a group of certain parts of the brain known as the ‘Default Mode Network’, or the DMN. The DMN is active when we’re at rest, and not focusing our attention on a task. There is another group known as the ‘Task-Positive Network’, or TPN. The TPN is active when we’re actively completing a task.
Some studies have suggested that for people with ADHD, the DMN may not ‘switch off’ when the TPN is active, and the TPN might not be functioning at typical levels – both of which might affect the ability to maintain concentration and avoid distraction when working.
In ADHD, the DMN has also been found to interact unusually with a group of brain regions known as the ‘cognitive control network’, a region that is usually active when we’re utilising cognitive functions such as shifting between tasks, storing items in our memory for recall during the current task, and controlling impulses.
For people with ADHD, activity in the DMN may be increased when the cognitive control network is active, which may explain why those with the condition have trouble with controlling their emotional responses or behavior, forgetfulness, and multi-tasking or shifting attention from one task to another.
We hope this post helped you understand a bit more about how ADHD affects the brain and how it functions. If you know someone that you think might benefit from reading this post, please share it with them! We’d love for our resources to reach those who need them.
Resources
NIH MedlinePlus: Understanding ADHD: What you need to know
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