I've never been on Abilify, but like any anti-psychotic it can be used for bipolar depression as well as mania. These drugs often work well to stabilize mood when the usual meds (Lamictal, Depakote etc.) aren't enough. In my own experience, it was the Zyprexa that pulled me out of a severe episode of depression in which I became suicidal and was hospitalized.

Sorry about the bipolar 1 diagnosis. I was dx'd with the same thing when I was inpatient a couple of years ago and four mental healthcare providers have since confirmed it. It is what it is. Best of luck.