I have been off those drugs for eight years, was on them for a total of one year, and lost 40 points on my I.Q. score.
Mind if I ask what you were taking during that year, and what you've tried since to get back to where you were...?
It's quite a worrying thought for me as I've been on and off anti-depressants (SSRIs) for the past 8 years, however my personal experience as far as I'm able to gauge it 'from the inside' is that I'm a hundred times smarter and better functioning when I'm not in a depressive slump.
It's interesting as I have read that anti-depressants can promote neurogenesis, however, I have also read some stories about people who have had a terrible, sometimes terminal, involvement with antidepressants. For example paroxetine (Paxil, Seroxat etc.) was a life saving wonder-drug for me but has doubtless contributed to a not insignificant number of suicides.
I'm sure you've considered this, but do you think it's possible that the illness that led you to antidepressants in the first place could have been the cause of your cognitive decline (e.g. I've read recently that excess cortisol can be a cause of neuron death and shrinkage of the hippocampus)... Sorry that's a very presumptious thing for me to say, and probably very annoying, but I thought it was worth mentioning as a possibility, at the risk of incurring your wrath
Anyway, I'm sorry to hear you've had a hard time of it.