ADHD is a genetic difference in brain function, in which the ADHD person’s brain is driven to focus on stimuli that it finds inherently interesting. This is different for each person: video games, sports, music, art, writing, science, or other things. He or she cannot command the brain to find a particular subject interesting if it really isn’t.
The unique way the ADHD brain focuses on and processes stimuli can be best understood by breaking it down into these characteristics:
Hyperfocusing. The ADHD brain doesn’t just focus on interesting stimuli: it hyperfocuses. It hyperfocuses, in fact, to the point that all other stimuli are blocked out. This means that the ADHD person doesn’t hear or see what’s around him unless it’s directly involved with the subject of his focused attention. Hyperfocusing can be a good and useful talent, if centered on the right thing at the right time.
Distractibility. Conversely, if the ADHD person isn’t hyperfocused on something, his brain is searching for something interesting, and when he finds it, his brain will hyperfocus on that. Thus when an ADHD person is hyperfocused on the wrong thing at the wrong time, we say that he is distracted.
Overstimulation. When the ADHD person’s brain is constantly monitoring the environment for any possibly important stimuli, it can become easily overwhelmed. This can lead to overstimulation, frustration and irritability, causing “snap attacks.”
Hyperactivity. Sometimes when the ADHD person’s brain is searching for something interesting to focus on, his brain urges the body to get up and move around to find something interesting. This is then called hyperactivity. Older children and adults usually don’t actually get up and move around, but their bodies want to, and they may feel or appear restless. Not everyone with ADHD has the hyperactive component.
Understimulation. Sometimes if the ADHD person can’t find anything interesting in the environment, then his mind may just shut down. We call this falling asleep. ADHD people can fall asleep in the most amazing places: on the back of a motorcycle, in the middle of a concert, and of course, in the front row of a boring college class.
Impulsivity. Because the ADHD brain is genetically predisposed to respond immediately and reflexively in situations, the ADHD person is often prone to saying or doing things without stopping and thinking first – which may end up causing them problems.
Open a printable pdf explaining the above characteristics in more detail. (2-page pdf; 49 K)
Find out more about the different types of ADHD.
In the last decade, brain imaging techniques have lead to a phenomenal increase in our understanding of the way the brain functions, including differences in the ADHD brain. In 1991, Alan Zametkin of the National Institute of Mental Health published the first research showing actual views of the differences in the way the ADHD brain works.
Since then, many other studies have looked at brain functioning in ADHD people. The most extensive library of SPECT (single photon emission computed tomography) scans of the brain is at the Amen Clinics in San Francisco and Los Angeles. Dr. Daniel Amen has done over 20,000 brain scans of people with ADHD and other problems of brain functioning.
Dr. Amen reports, “At rest, most ADD people have normal activity in their brain. When they perform a concentration task, however, they experience decreased activity in the prefrontal cortex, rather than the expected increased activity that is seen in a normal control group.”
These SPECT scans from the Amen website show brain activity (not a physical picture of the brain itself):
Normal brain activity.
ADHD brain at rest.
ADHD brain concetrating.
Read more on this site about diagnosing ADHD.
To see more SPECT scans and learn more about the Amen Clinic, visit BrainPlace.com.
