If pristiq (desvenlafaxine) worked for 2 months beautifully (then stopped) what neurotransmitters does my brain need?

Worked for what?: Next treatment steps depend on why you were prescribed Pristiq (desvenlafaxine) in the first place -- and what it "worked for"? Please discuss with your own physician, who will want to know what's happening with you so s/he can improve your results. It may not be specific neurotransmitters at all, as these are not the sole explanation for difficulty you might be having.

Different question!: Soon after ssri anti-depressants were created, it was found that some people soon lost their great effect (pristiq (desvenlafaxine) is mixed serotonin/adrenergic.) the reasons werenot known. Recently, it has been found that even if with no symptoms of the other "pole", this loss is much more common in those with even mild "bipolar" depression than with "unipolar". That's the question to address with a psychiatrist.