I have been on provigil 200mg for almost a year now and I am just getting to the point where I may need to increase my daily dosage or at least add an afternoon dose. I have had two sleep studies and mslt which ruled out narcolepsy. My official dx is idiopathic hypersomnia (eds). I just tired 24/7/365. No amount of sleep is ever enough and if I sit still for five minutes I fall asleep no matter where I am. The provigil helps me get thru my workday...Barely. Lately I have noticed it wears off earlier, which is around 3 pm. I also have apnea and try my damnest to use my cpap, but typically find that I take it off in my sleep (not aware that I have done so until morning). Even when I do manage to keep it on, it wakes me up so many times that it seems to be defeating the purpose of using it. Anhow, I have an appt with my dr and plan to discuss all this with him and see what we can come up with. When the provigil works, it works really well. But the minute it wears off, the brain fog is back and I must sleep. This is all so frustrating as it developed out of the blue about two years ago. I have always needed a little more sleep than most people I know, but out of the blue it got so bad that it dramatically affects my ability to function on a day-to-day basis. It's always there, just sometimes worse than other times where I do nothing but work and sleep.