Sorry for jumping into this so late, but I'm new to the forums.
I ended up on Lexapro in a round-about way. I was sufferring from severe tinnitus which was actually preventing me from sleeping which increased my anxiety which increased the effects of the tinnitus, etc. Once I went on the Lexapro, the tinnitus didn't go away, but it became background noise that didn't really bother me. Now the noise is more an indicator of anxiety rather than a contributing factor. My wife has said that there were dramatic differences, but she couldn't (or didn't want to) tell me exactly what they were. But she can tell when I miss a dose.
With that said, the Lexapro "levelled me out" and it had a significant impact on my creative process. Before the meds I would procrastinate, get blocked and then have a burst of creative insight and manic productivity. Obsessing and working through the night was pretty common. However, when I objectively compare my work before and after the meds, they're really pretty similar. It just felt like I was being more creative because of the "eureka" moments. It's hard to tell whether I would have come up with identical insights on and off, but I think that it's mostly a perception thing and not an objective stifling of creativity. Off the meds, the same process are going on but they're more chaotic and off my concious radar. On the meds, I'm more aware of them and in control, so it feels less like creativity and more like work.
Just my experience. Your mileage may vary.