That's exactly what I was going to say. It could be that high caffeine users are biologically predisposed to need frequent doses of a stimulant to maintain a le

That's exactly what I was going to say. It could be that high caffeine users are biologically predisposed to need frequent doses of a stimulant to maintain a level of alertness that is merely normal for the general population, like some kind of ADHD spectrum disorder. But that's probably just the drug talking.