I was originally on Lithium and antidepressants when I was first dx. I had a crisis with the Lithium and had to discontinue it. Fortunately Lamictal was approved as a mood stabilizer for bipolar people about this time.
I was still on antidepressants but my doctor thought they were destabilizing me and took me off of them. She said that bipolar people sometimes did better without antidepressants.
So I am on a very low dose of Lamictal 150mg which was reduced from 300 mg. I get double vision as a side effect and take it at night. I am stabilized enough to manage my symptoms and have a good quality of life right now.
If you are not experiencing any side effects currently and your pdoc thinks that an increase would help I think you might consider it.