My advice would be to wean off of it instead of going off completely. I think that quitting anything abruptly will put any bipolar person into a tailspin.
For instance, if you usually start smoking at noon, start smoking at one pm, then the next few days try to wait until two, etc.
I myself am pretty dependent on it, and am considering giving it up. But I will definitely do the taper method. I've gone through every kind of physical withdrawal (alcohol, opiate, benzo) so I know I can do it, its just hard to give up my safety blanket.