Yeah caffeine is a siren song for a select few. It's not necessarily an 'everyone and every form of ADHD thing', but it seems to present together often enough.

In my case it's tricksy because the line between "this much coffee will help sleep" and "this much coffee will make you feel like it re-activated the magic conversion machine the actual ADHD meds just shut down" is about 1 oz one way or another from a 5oz cup (a real small amount in sane units, I didn't convert).