insomnia
"I've had chronic insomnia (clinical diagnosis, sleep studies, neurologists, etc.) for over 25 years, starting in high school and gradually getting worse over the decades.  No drugs aside from powerful depressants (barbits, benzos, tranquilizers, etc.) had helped me at all.  Ambien CR has been a miracle medication for me.  My insomnia is so constant and severe (I literally won't sleep a single minute some nights) that my Dr lets me take it every night.  Many people talk about the possible side-effects of long-term usage, but that ignores the very definite effects of chronic insomnia.  I have no next-day side-effects, but I will have rebound insomnia if I stop.  Taking with a glass of water helps for me; so does good sleep hygiene rules."