insomnia
"I use Ambien CR 12.5mg (strongest), and I still wake up at 3am.  Can't take another Ambien. To avoid any risk associated with driving to work and then dealing with the drowsiness while at work, my doctor put me on Sonata.  Even if I wake up at 3 or 4, I am able to enjoy the rest of my night in restful sleep with no morning drowsiness at all.  "