With Lexapro, I had to FORCE myself NOT to sleep - I was constantly exhausted for the first two months. I eventually got used to it and had no other side effects.

I'm on Wellbutrin now and the only sleep impact it's had is that I have very vivid dreams. It's rather annoying - I'd like a peaceful night of sleep. I'm sleeping the whole night through, but the dreams are very active and sometimes violent - not quite nightmares since I usually "win", but certainly not relaxing.