ADHD isn’t a matter of having too much energy – it’s actually the opposite. ADHD brains are actually sluggish and unable to stay locked on.
What happens is that psychological arousal – the ability for the brain to register something as important and interesting that it needs to pay attention to – needs a lot more stimulation in ADHD people.
That means that things need to ‘pop!’ more, or else they just fade into the mental background. If it’s not moving, waving its arms, being generally on fire or otherwise grabbing us by the throat on a second-to-second basis, our thoughts just slide right off it after a short period of time.
For a quick demo, try thinking about the number three for five minutes. No tangents, no distractions, no side notes. Not things there are three of, not multiples of three, not the shape of the numeral, not how you spell the word, not three o’clock. Just three. I don’t think you’ll last one minute before you lose traction on it; you just can’t make yourself think it any more, and literally anything else will take priority. It stops being a stimulating thought, and your attention refuses to stick to it.
As a result, ADHD people bounce around from one thought to the next to the next, because nothing stays. They’re constantly flailing for context and running to catch up, because literally anything else is louder and grabbier than the thing they’re currently trying to focus on.
Give an ADHD person stimulants, and the threshold for arousal is lowered. Things no longer have to be on fire and playing the trumpet to hold their attention for more than a few seconds – and they can actually maintain stimulation from the result of thinking about them.
Instead of being lagged to hell and teleporting around the map, instead of running from pillar to post in a world of phantoms and mirages that disappear by the time you reach them… they can actually hold onto stuff, pin it down and stay locked onto it.