This is false and a common myth. If this was true then we would have the perfect test for ADHD, just give someone some stimulants and see how they react.
"Correspondence (letter to the editor): Paradoxical Reaction in ADHD":
Often you hear this saying that people with ADHD feel relaxed when they take a stimulant and don't feel any increased energy or mood lift, which of course is false. That's what I was referring to.