I've heard that antidepressants can cause some people to become agitated.. mean, I guess. I think it's due -moreso- to the underlying cause (like someone effected with bipolar may suddenly cycle to mania).
If someone gets mean after starting a new med, they should contact their dr asap.
That's a hard question
Anxiety alone can cause you to be mean...and adjusting to the meds could too.
I would suggest seeking therapy..they are the best judges as to weather or not you might be bi-polar.