narcolepsy
"Dexedrine is great, aside from the increased anxiety.  I currently take 90mg daily - both the 5mg tabs and the 15mg spansules.  I require two 20mins naps/day, but will still have sleep attacks if I'm inactive.  It may not sound overly great but without Dexedrine I'd never leave my bed/couch, as I fall asleep every 10 mins. So essentially, it does a world of difference."