tranquilizers/antipsychotics have almost immediate effects, -if- the dose is sufficient. when hallucinations are present, it can take longer for the drugs to restore lucidity. with lithium on board, I would expect a relative quick onset of a calming, anti-agitation effect.

some doctors use a tranquilizer w/ lithium, depakote, etc., and then taper the tranquilizer once the mood drug takes hold.