Again (as is often -- or almost always -- the case), I support SzAdmin's comment here. There's a concept in internal medicine called "aggregate accumulation" which refers to slowly constructing a pharmaceutical "cocktail" that produces the best combination of effects possible for a particular patient.
I've never seen a "perfect" cocktail... meaning one that "restores the pt. to 'complete,' 'top of the bell curve' functionality. But I have seen a bunch of schiz pts who were severely disabled and floridly psychotic make astonishing headway towards relative functionality even when, as in the case of one I knew they had been "born into psychosis" as the result of very early life encephalitis and had several of known schiz genomes.
If one's psychosis is the result of a mixture of etiological causes, it's likely that the individual progressions of the genetic, epigenetic and environmental "insults" will vary over time, requiring medicinal modifications, not only in dosage but in wholesale withdrawal from one med and replacement or up-dosage of another.
I've known several top-notch psychopharmacologists who almost seem to be "miracle workers" in regard to their ability to "stay with" schiz, bipolar, hysteric borderline and other psychotic pts for decades.