chronic fatigue syndrome
"I have chronic fatigue with my MS.  I tried Provigil several months ago but it gave me a severe headache and I felt spaced out.  Tried Nuvigil just today and felt jittery in the early part of the day and a bit light headed but I think I'll stick with it and see if I get the benefits others describe.  I didn't take a nap as usual today and I hope to feel more focused and energetic with my job soon."