They wouldn't put you on Prozac for Bipolar so you must have had depression. Most Bipolar people are given small dosage lithium.
And yes, a chemical imballance needs to be addressed with Medication, but wihtout talking therapy it is much less effective. Start with the talking therapy, if the Psycologist thinks there is even a smidgen of a chance there is an imballance then they'll send her to a psychiatrist. But Talking therapy is always where you start.
Remember there are high incidents of people who get on Anti-D's killing themselves. The reason for this is when you are really Depressed (as anyone who's actually suffered from Depression can tell you) You really can't do much of anything, and killing yourself takes alot of work. The Anti-D's give you enough energy and drive to actualy put out the effort required to do the deed. That's why it MUST be coupled with talking therapy. Some outlet, to get her to a point where she doesn't want to kill herself while the medication (if needed) helps her.
I swear I know what I'm talkig about! I sleep with a woman who does this work everyday!