narcolepsy
"I have been taking Provigil for a month. I noticed a decrease in my sleepiness right away. I was falling asleep at work and while driving so many times a day I couldn't count how often.  My insurance wouldn't approve it and it was way to expensive for me to pay cash so it took me a couple months before I was able to get it filled.  I called every pharmacy I could think of to compare prices and costco was way cheaper than everyone else.  Their price for 30 of the 200 MG was only 39.00 compared to 700.00 at some other places.  I definitely recommend getting it filled there if you have to pay cash."