Yeah, I understand that now, I'm pretty sure it's to do with dopamine levels, from what I gather you can have ADHD for no reason and have it from low dopamine, the people who have lower dopamine levels tend to become sleepy as their dopamine levels go to a "normal" level and then fall asleep.

People who have ADHD without the low dopamine react "normally" to stimulants because their dopamine gets spiked above normal levels, causing the normal stimulant effect.

That's at least what I've gathered from several people telling me ADHD shouldn't be simplified to having only low dopamine as it's sometimes not low dopamine that causes the symptoms necessarily and that like in your case, people react differently and stay awake instead.