Karen, I really hope that your daughter gets the help that she needs, the right diagnosis and the right meds.
Personally I love lithium, it is less sedating, it is antidepressant as well as antimanic, it makes you 6 x less likely to kill yourself and it is as cheap as chips!!! (except all the blood tests!)
There is a proof of concept study for the use of SSRIs in bipolar (I think it was BP2 no rapid cycles), not a large study but they were effective. SSRIs are used in Australia (not used in US coz of legal reasons) even in the absence of mood stabilisers in mild cases but this doesn't sound like a mild case- and yes you are right in saying that you have to watch out for "switching" to manias with antidepressants .