How do you cross-taper when switching from an SSRI to an SNRI?  

It depends on which SSRI and SNRI are involved, as well as the dose of the SSRI. If switching from a low-dose SSRI, a cross-taper is not typically necessary given that both SSRIs and SNRIs increase serotonergic transmission and therefore a withdrawal effect will likely not be felt. If switching fro...