narcolepsy
"Idiopathic Hypersomnia - Nuvigil has been available for prescription for two weeks; I have been taking it for five days.  50mg once in the morning.  I do not have trouble falling asleep at night, which I did on Provigil.  Nuvigil is rather expensive to fill, more than $1 per pill for my copay.  It has helped my daytime sleepiness somewhat, but not taken it away completely.  I still get strong urges to nap, but they are more resistible.  I sleep less at night, more like 7-9 hours than 8-10.  The big problem is that Nuvigil appears to be triggering migraines for me.  I have chronic migraine syndrome and I usually get one per week, but for the first four days on Nuvigil I got three migraines.  I will have to discontinue it if this side effect doesn't stop."