It is fairly standard practice to augment bipolar treatments with antipsychotics. However, I personally think they are overused. I have psychotic features to my bipolar 1, so at times I do need an AP to bring me back to reality. However I will not take it long term as the sedating effects are too much for me.

I'm not sure olanzapune would be necessary for cyclothymia. But I am not a doctor so I can't say. All I can say is do your research - olanzipine causes weight gain, for example. You may not want to contend with that if you don't feel like an AP is necessary. Personally I would try mood stabilizers first and then add an AP if necessary, if you have already done that.