narcolepsy
"This may be a little long so I hope you took your medicines today, LOL.  this is my 3rd month on Adderall and it is absolutely a miracle drug for me. I have suffered with extreme fatigue and excessive sleepiness since I was a teenager, I'm  38 now. My doctors have tried me on everything from sleeping pills, to antidepressants, nothing worked. A friend suggested Adderall, I researched it, talked to my doctor about it and we tried Provigil first, which did help, but I was still falling asleep driving, reading, etc. Switched to Adderall. I was so happy I nearly cried when I was telling my doctor how much better I feel. I wish I would have tried this years ago."