[Zikes]

It really depends on what sort of definition you have for immortality. I would say in this case it would be the ability to live until you choose for yourself not to live any longer, not necessarily that you can never die.

I disagree that it would drive people insane, though, excepting the increasing chances for mental illness to set in as we age which I would assume would be solved as a part of the implementation of immortality as a concept. Our perception of time changes as we age, the passing of a single year takes on less and less meaning each time, becomes less of a milestone and more of just another regular occurrence. Depending on how we go about achieving immortality, time may take on dimensions we can't currently understand, and we may even have the option to choose not to perceive its passing at all.