narcolepsy
"I was diagnosed a year ago. I have cataplexy as well. I've been taking 250mg daily of Nuvigil for about 8 months and I'm very happy with it. The only complaint is that (as another person said) it doesn't last all day, I also crash out in the afternoon. If you have this problem I suggest eliminating idol time. I have noticed that if I keep myself busy I have no problem going through the day normally. I haven't experienced any side effects whatsoever.  Most of the other medications may keep you awake all day, but seeing as the side effects can be devastating for many people, I'll take the extra effort to keep my idol time to a minimum and unlike the other medicines I've tried, I don't feel like I need a higher dose every 3 months."