I took anti-depressants for three years. My first course was Fluoxetine (Prozac to my US cousins): within a week I was a zombie. I would sit and stare at walls, or out of windows, until someone snapped me out of it.
After a month of this I was moved to Citalopram. This seemed better; there was less staring at walls, certainly. I spent over two years on Citalopram.
Then one day I stopped. It was kind of an accident; it was Easter weekend, I wasn't paying attention and ran out without a prescription to get more. So I ended up going cold turkey, which is the thing you're really not supposed to do with any SSRI.
I can tell you now, within three days I felt like I had woken up from a trance. I didn't realise it at the time, but the Citalopram made me feel like I was wrapped in cotton wool and wearing ray-bans. The feeling was exactly like the feeling of a dental aesthetic wearing off, except all over. I hadn't noticed because I'd come from Fluoxetine, which was even worse. So I thought I was onto a good thing with the Citalopram.
So please don't go around calling it a "myth". For some people, SSRI's really do have that kind of effect. In fact I suspect it's more pre-valiant than people realise, either because of long term use, because people think it's "normal", or because most people come down gradually and never really notice.
Oh and for all that, I really do believe I was much better off taking the SSRI's at the time than I would have been without them.