I'm not sure if there are any studies about this, Little Turtle. They always tell me Prozac isn't habit-forming, but I remember when I first started taking it -- this was YEARS ago -- they were loath to give long-term prescriptions because the drug was fairly new and they weren't sure of long-term effects. But over time it seems as if most resistance to long-term Prozac therapy has dwindled away.
All I can say is this last time, when I tried to DC it, I reverted to the same state I was in before I ever started taking it. There was nothing particularly different about it.
As to CBT I think it is a very logical, well-meant approach, and useful to a point, but have always found that my own deep disturbances seem far too deeply buried to be much affected by even the most excellent reasoning.