Trazodone
insomnia
"I have taken trazodone off and on for about five years. As long as I'm taking it every night it works just fine, but if I skip a night I won't sleep at all. No physical dependence, but if I've been taking it regularly and then stop I can't sleep more than an hour a night for at least a week. Works well when taken nightly, but has a horrible rebound effect."