One thing that's important to understand about ADHD is that individuals with the disorder typically have lower levels of activity in the brain. Their arousal is typically lower than someone without ADHD. So what do they do? They seek stimulation in their environment, which looks like they're distracted, which looks like they're not paying attention, which looks like, essentially, that they're all over the place. But what they're really trying to do is stimulate themselves so that their activity levels are higher, are greater.
If we can make the environment really stimulating for appropriate behaviors, then their distractibility may be minimized.
