My husband has been on antidepressants for many years, but several of the SSRI's have "pooped out" for him. (This is actually what they call it when it abruptly stops working.) He was suffering from mental fuzziness and decided to allow all the drugs to clear out, so took nothing for a month. the fuzziness went away, but the depression is back. He has started Pristiq, a new drug for him, and after four days he is still pretty low. Those of you who have taken it -- do you remember how long it took for your mood to lift?