hypersomnia
"I have suffered excessive daytime sleepiness for a long time.  It was so bad that I would fall asleep at work, on the bus, in the car, etc., at least 4 times a week.  After having sleep studies done, my doctor ascertained that I do not have obstructive sleep apnea, and I do not have narcolepsy.  I work only daytime shifts.  Nuvigil (armodafinil) 150 mg tablets were prescribed by my doctor, and they have changed my life.  I have not fallen asleep at work since.  I feel capable and energetic.  I do not feel any depression, nor do I feel overwhelmed by obstacles. It is a MASSIVE change in my quality of life. 
One problem: My insurance company won't cover it."