My doc told me that Lexapro is sort of a mirror of the chemical structure of Celexa. Apparently, it works in a similar way, but with a smaller dose. So far, it has been working well for me. I'm not getting the lethargy I experienced with Celexa. I still have the energy to exercise. I have lost 5 pounds since I started taking it (maybe due to my new, busier job and all the flights of stairs I'm running up and down every day). I'm keeping a closer eye on my weight this time round. I wasn't paying attention to my weight when I was on Celexa. The extra weight I gained sort of snuck on me from behind -- on my arse. LOL