narcolepsy
"Xyrem has changed my life.  For the first time, I can awaken from sleep feeling refreshed.  For the first time, I can achieve a deep sleep.  The quality of sleep that I get while on Xyrem is a miracle.  Before Xyrem, I used to sleep extremely light all night long, while waking dozens of times and tossing and turning.  Between constant REM (dreaming) and spurts of very light sleep, I was so exhausted in the morning and I could barely function during the day.  Also, I had a hard time with falling to sleep at night.  And trying to maintain a set sleep schedule was nearly impossible."