I have been on 20mg of Lexapro for a little over a year. I saw my doctor yesterday and told her that despite the difference Lexapro had provided, I was still not very "happy" (and never had been... it basically made me dysphoric rather than crying all the time), and the fact that I have gained 19 pounds from the medication alone (no change in my activity level over the time I was on the drug) did not make me too happy. So, she gave me a sample pack of Pristiq--as well as a prescription--and told me to take the Pristiq one day, and then the Lexapro the next. She wants me to alternate the two meds for one or two weeks, and then switch over to Pristiq completely.

My questions: Is this really necessary (i.e., if Pristiq is an SNRI, why would I still experience withdrawal from Lexapro)? Furthermore, isn't there a chance that I could experience Serotonin Syndrome by switching back and forth like this (or is this a common procedure)?

Could people who have switched from an SSRI to Pristiq (or anyone who has switched from an SSRI to any other type of anti-depressant) please reply and let me know how they were informed to do so, and how it worked out in the end? I would really appreciate as much feedback as possible, b/c I am considering just switching to Pristiq right away... I have tried the whole cabinet before, and never was I "weaned-off" of one before starting the other; I was always just switched over on the day of the visit.
Thank you all for your help!!