What are the dangers of taking antidepressants and sleeping pills together?

This is a question: for a psychiatrist, but generally you shouldn't take two medications that might potentiate each other (1 + 1 = 3). One popular sleeper, Trazodone, is actually an old style antidepressant, which isn't used for anti-depression anymore because its such a good sleeper. But consult with an MD before adding an Ambien, or Lunesta (eszopiclone) or any other OTC sleeper (Melatonin, Valerian Root, etc.) Be careful.