Actually clozapine is the most effective antipsychotic for PD psychosis and LBD typically we use 25-50mg/day so much tinier doses than in schizophrenia. Seroquel is largely useless. There is at least one study for abilify where it was tolerated but not effective. I have used it for psychotic depression in a pt who also had PD. Some people report significant worsening of Parkinson’s with abilify but I haven’t seen that. In general first line for psychosis is LBD is AChEIs like rivastigmine. In Parkinson’s psychosis try to remove anticholinergics, amantadine, dopamine agonists if possible and reduce sinemet If still problematic and possible. Seroquel is most commonly used but is rarely helpful other than sedating the pt and I would rather use other drugs to calm/sedate pts (e.g. trazodone in bad brains). Clozapine is actually a very powerful dopamine antagonist but because it very effectively fast dissociates from D2 receptors it does not induce the general badness you get in other neuroleptics. It’s certainly even more complicated than that but we don’t fully understand clozaril even though it’s receptor profile is well characterized it’s unclear how this translates into its effects. It’s woefully underused in PD psychosis and LBD psychosis.