Why does coffee make some people with add super tired and some get super hyper?

A Proper Fit Helps: It's complicated. You'd think you'd want to stay away from a stimulant if you were already stimulated but things can work otherwise. Like, a stimulant can stimulate certain nerves than then inhibit others and this apparently happens with many who have ADHD. It has to do with drug receptor sites and how they are shaped and how other chemicals fit into them to activate or inhibit those nerve cells.