luffy hasn't shown any signs of narcolepsy … and he needed the sleep ... in order to heal, that's the same thing zoro does.
I agree on both points.
I once thought Zoro was narcoleptic – I have no idea why I didn't see it as "battle fatigue" then, I guess I just assumed it was narcolepsy because he seemed to be sleeping all the time -- both on and off the battlefield. When Ace was introduced as an actual narcoleptic, I was disappointed! I thought : "no way, we already have a character who is like this, we don't need a second ..."
But I figured it out after the Mr.1 fight : Zoro isn't sleeping during battles, he's blacking out! He's losing consciousness because he's lost too much blood and because he's pushed himself beyond his limits. (As for the non-battle sleeping : he's conserving his energy for when he needs it most, just like a lion or tiger would) ... that's very different from narcolepsy!
Luffy seems similar to Zoro -- he doesn't sleep before a battle, but he sleeps twice as much as Zoro after a battle. Not narcolepsy; fatigue.
Garp however does seem to be narcoleptic, as does Ace -- both fall asleep for no reason, and not in the heat of battle. Unless you count their little "fist of love" tiff as a "battle"...