i have narcolepsy. i fall asleep randomly, usually without even feeling tired. sleeping at night is excruciatingly difficult most of the time, even if I'm exhausted. my brain is messed up :D
i took ambien for a couple of years, the docs just thinking i was a bad insomniac. now apparently i've discovered that ambien exacerbates narcolepsy. but god it was so nice sleeping for 7-8 hours a night back then ;-;.
I'd get back on it but i want to drive and i can't if i'm falling asleep 4-5 times a day. when i'm off of it it usually only happens once or twice.