This is a fairly old thread, but in case someone reads it I'll add my experience with Trazadone.
My pdoc prescribed Traz. for sleep. I had taken it for about a week, then I took the same (recommended) dose one night and had a horrible, very frightening reaction. I felt like I had overdosed. Flashing lights with my eyes closed, humming noises, a strong sensation that I was going to black out. I was fighting to retain consciousness. The experience took about 15 minutes to pass. I know that most people do well with Trazadone, but maybe some don't. I will never touch the stuff again.