Lithium and valproic acid are definitely the go-tos as good anti-manic mood stabilizers, especially of the ones that don't interact with antipsychotics. Lamictal is usually better for the depression end of the disorder. Some others may work, but don't have the proven efficacy behind them. I have done well taking carbamazepine (Tegretol), but it is known for the interactions I mentioned. I doubt many psychiatrists would want to switch to it without hefty backup medications or a more "classic" bipolar. When I first started it I took near a whole pharmacy.

Are you only taking 300 mg of the valproic acid? That is a small dose. I took it in the past, including with Invega, but was on over 1,000 mg. I forget the Invega dose I took. It was near 12 years ago. What are the side effects you're experiencing? I remember what mine were.

At only 400 mg of the Lithium, I assume you're being weaned off? That is also a small dose. I took 1,200 mg, and then 900 mg. I never found it particularly helpful for me, either. It gave me numerous side effects, including hypothyroidism. Frankly, the hypothyroidism was no biggie compared to others. Perhaps your thyroid will recover after stopping it. Mine didn't because doctors kept me on Lithium despite the thyroid issue. My Synthroid dose went up and up. I've been off of Lithium for about 9 years, yet still require 150 mcg of this thyroid replacement med. Oh well! It's a small pill.