narcolepsy
"I was diagnosed with narcolepsy around 7th grade, and pretty much sleep through middle school. I took Ritalin about up to 10th grade which moderately helped me stay awake, but I still would always crash multiple times a day due to the fact that it doesn't completely eliminate excessive sleepiness and trying to perfect your taking-schedule really is crucial with any narcolepsy prescribed medication. When my neurologist started me on Provigil, I was pretty shocked by the lack of side-effects it had, and it was a somewhat natural awake feeling as others have mentioned. I went from taking 2 (200 mg) pills a day to taking 2-3 (200 mg) pills a day depending on my schedule, exercise, or exam studying. "