As a doctor who treats ADHD, I'm often asked about difference between an ADHD brain and other brains.
Studies show and brain scans reveal that several areas of the brain may be affected by Attention Deficit Hyperactivity Disorder (ADHD) including the frontal lobes, inhibitory mechanisms of the cortex and the limbic system.
The frontal lobes are often referred to as the "Executive Brain"
because they are involved in higher order cognitive tasks such as
attention, organization, and impulse control. In other words, a healthy frontal lobe can literally help us make better decisions and make us better able to analyze events, situations, tasks, etc.
Brain scans comparing brain function in children with ADHD and a control group have shown less blood flow to the frontal lobes in the children suffering from ADHD.
In addition, Dopamine production has been shown to be less in children with ADHD. Dopamine is a hormone produced by the brain that is involved in regulating memory, attention, problem solving, and motivation - all things that are compromised in children diagnosed with ADHD.
See the image to the right. Notice that the brain affected by ADHD shows excessive slow brainwave activity (theta and alpha ranges) compared to non-ADHD activity.What this means is that there is slow brainwave activity in the cortex areas of the brain, which indicates a lack of executive control.
One study looked at children with and without ADHD over a 10-year period. At various ages, children's brains were scanned using magnetic resonance imaging (MRI). The researchers found that the brains of boys and girls with ADHD were 3% to 4% smaller than the brains of children without ADHD.
Also, children with more severe ADHD symptoms had smaller frontal lobes, temporal grey matter, caudate nucleus, and cerebellum. These brain regions are involved in concentration, impulse control, inhibition, and motor activity, which are all challenges for children with ADHD.
These studies have shown that reductions in blood and brain volume in children with ADHD are associated with poorer performance on tests of attention and inhibition and measures of behavior.
This is the reason why Ritalin and other stimulants such as Adderall, etc. are used to treat ADHD. These stimulant medications can increase the level of dopamine in the brain and which can result in improved focus, increased attention to detail, greater task awareness, etc.