Divalproex Sodium (Oral Route) Side Effects - Mayo Clinic mentions neither fainting nor syncope.

No, Depakote does not protect against psychosis. In some cases, it causes psychosis as a side effect. For protection against psychosis, you need an antipsychotic. I guess in your case it is Invega, but you are still having breakthrough symptoms, which is why I asked on your other thread what other antipsychotics you had tried before deciding to settle for Invega. Invega also has on average more side effects than some other antipsychotics.

Depakote and Lithium act synergistically.

I wonder whether you have tried Levothyroxine for Lithium-induced hypothyroidism.

All antipsychotics can cause orthostatic hypotension. This can cause a syncope. It has happened with me but luckily I just barely missed hitting my head against a glass table as I fell. I believe that out of your three psych drugs, the most likely to have caused a syncope is Invega. But this is not something specific to Invega: all antipsychotics can do that. That is why it is of supreme importance to always be well hydrated. When you fell in the bathroom, was it first thing in the morning?