What is the difference in the treatment of bp2 and the treatment of cyclothymia? (what meds are commonly used for one and what for the other?)

Significant: Cyclothymia does not require a mood stabilizer. It means that you cycle between normal (euthymia) and depressed. The mainstay of treatment in cyclothymia is an antidepressant. Bipolar 2 definitely requires a mood stabilizer to prevent mania. This is an oversimplification, since the treatment of the depression in bipolar 1-2 is not at all clear cut, and anti depressants are not always effective.

Very similar: Since both disorders involve mood swings, with bipolar being the more serious of the two, both disorders typically require mood stabilizers such as lithium in varying dosages, depending on the needs of the patient.