insomnia
"I tried Ambien about a year ago for my inability to stay asleep.  I have several times a year where I wake up between 2:30 and 4:30 every morning for a few months at a time.  For me, Ambien worked.  I slept soundly through the night until my alarm woke me up and I really enjoyed it. I was unaware of my certain side effect until my wife insisted we had a conversation I had no memory of.  So I started asking around to people I worked with and sure enough I had quite a few instances where I had full conversations with people the mornings after I used Ambien and had no memory of it.  It got to the point where I had to speak to my bosses and ask them if I had any assignments I was not up to date on.  Luckily, I was not."