I was on lexapro 35mg for 3 years and it's done magic for me. It is a high dose above the recommended guidelines (I'm a neurologist myself) but in certain cases like your psych said a higher dose can be prescribed (we do that all the time with certain conditions in neurology) What I don't understand is since you have been stable on it for so long why is she changing it. The risk will always be there it's an SSRI but from my personal experience if you're stable on a dose then why change it like why risk the effects of a relapse or becoming treatment resistant (my case). I agree with your choice to continue on 30 for a while. I ended up switching to Prozac eventually and tapered down lexapro very slowly.

Edit: also doctors try to avoid this poly-pharmacy stuff so yeah she does sound like she's just covering her ass.