narcolepsy
"I have been on Nuvigil for about 3 months now and see a little bit of difference. Previously I was on Ritalin which worked pretty much the same as Nuvigil. My doctor is currently giving me a trial period for 150mg once daily. I take one daily at 6-8 am and it lasts me till around noon. I then start to crash and when driving I still have a hard time staying awake. My doctor says it is because I need a higher dosage and will hopefully be starting that the next Drs visit. I highly recommend Nuvigil if you can afford it but if not Ritalin in my opinion works just as well."