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Key Takeaways
- ADHD brains have differences in structure, like smaller brain volume and parts maturing at a slower pace.
- The ADHD brain shows decreased blood flow to parts responsible for tasks like attention and planning, highlighting differences in function.
Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder. This means there are differences in the ADHD brain that affect a child’s development. ADHD does not influence intelligence. It does, however, affect a person’s ability to regulate attention and emotions, and it results in hyperactivity and impulsivity as well as organization problems.
While it is classified as a condition, more recent thinking views it as a form of neurodiversity. People with ADHD brain’s process information differently, but that represents a normal variation rather than a disorder that needs to be ‘cured.’ This neurodiversity perspective emphasizes recognizing these differences and valuing strengths instead of focusing solely on challenges or deficits.
Rather than trying to change ADHD traits to fit into a neurotypical world, this perspective stresses the importance of accommodations and support to help people thrive.
Differences in the ADHD Brain
ADHD has come under a lot of scrutiny over the past few decades, contributing to public misperceptions and stigma. In the past, some naysayers questioned if it was real or said a lack of motivation, willpower, or bad parenting caused it. Then, there was the explosion of stories suggesting that ADHD was overdiagnosed and overmedicated.
None of which is true, of course, but if you or your child has ADHD, you can feel vulnerable to these types of comments.
Knowing that there are biological differences in the ADHD brain—compared to the brain of a person who does not have ADHD—can be validating for someone dealing with the condition, as it provides additional evidence of the realities of ADHD.
The differences can be divided into three areas: structure, function, and chemistry.
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ADHD vs. Non-ADHD Brain Structure
Research over many years has shown clear structural differences in the ADHD brain. The largest review of ADHD patient brain scans was conducted at Radboud University Nijmegen Medical Centre and published in 2018.
The study found that people with ADHD had smaller brain volumes in five subcortical areas, and their total brain size was also smaller. These differences were more prominent in children and less noticeable in adults.
Parts of the ADHD brain mature at a slower pace (approximately one to three years) and may not fully reach the maturity level of a brain without ADHD.
Another significant finding was that the amygdala and hippocampus are smaller in those with ADHD. These areas are involved in emotional processing and impulsivity and had not been definitively linked to ADHD before.
ADHD vs. Non-ADHD Brain Function
Researchers use several brain imaging techniques to study how ADHD brains operate and function, including:
- Functional magnetic resonance imaging (fMRI)
- Positron emission tomography (PET)
- Single-photon emission computer tomography (SPECT)
In people with ADHD, blood flow to certain brain areas, such as the prefrontal regions, is altered compared to those without ADHD. Decreased blood flow in these areas suggests reduced brain activity.
The prefrontal area manages executive functions, responsible for tasks like planning, organizing, paying attention, remembering, and regulating emotions.
Research indicates that ADHD may be linked to atypical brain connectivity. Studies with resting-state MRIs suggest increased connectivity in certain brain regions in individuals with ADHD.
Research has found that children with ADHD do not have the same connections between the frontal cortex of the brain and the visual processing area. This suggests that the ADHD brain processes information differently than a non-ADHD brain.
ADHD vs. Non-ADHD Brain Chemistry
The brain functions as a communication network where messages are transferred from one neuron (brain cell) to another. There is a gap between neurons called a synapse, which must be filled with a substance called a neurotransmitter for messages to be relayed.
The key neurotransmitters for ADHD are dopamine and noradrenaline. In the ADHD brain, there is dysregulation of the dopamine system. For example, there is either too little dopamine, not enough receptors for it, or the dopamine is not being used efficiently.
Stimulant medications help ADHD because they encourage more dopamine to be produced or keep dopamine in the synapses longer.
How Is ADHD Diagnosed?
Brain scans cannot be used to diagnose ADHD. There is no objective test to diagnose ADHD. The diagnosis of ADHD requires a full evaluation by a qualified doctor, psychologist, or psychiatrist. Diagnosis includes:
- An in-depth interview with the patient
- A review of school reports and medical history
- Tests to measure attention, distractibility, and memory
While PET and fMRI scans can be useful for research, they really only give an insight into how the brain is functioning at the moment the test was performed. Brain scans do not take into account how the brain operates in different situations, unlike a clinical test during a detailed interview.
In addition, the scan data that has been studied is generally based on group averages and may not apply to any particular individual. The results have not been normed, which is when large quantities of data are gathered and compared.
ADHD is diagnosed as a neurodevelopmental condition, but it is important to remember that it represents a normal variation in brain structure, function, and chemistry. These differences can create challenges in your life, but that doesn’t mean that they are something that needs to be “cured.” ADHD also comes with strengths.
Understanding the underlying causes of your ADHD traits can be validating and give you a place to start when it comes to managing some of the challenges you’ll experience living in a society designed for neurotypical brains. Getting an accurate diagnosis is a great place to start. Depending on your unique experience, you may find that medications, therapy, ADHD coaching, accommodations, and social support can help.