Table 2.

Treatment, disease course, and key takeaways from each case.

Case #	Treatment	Disease course	Takeaways
1	PIM 34 mg	Improved PDP symptoms at 4 weeks	(i) Delusions may occur isolated from other, typically earlier, symptoms of PDP such as illusions and hallucinations
2	PIM 17 mg; excess sedation with 34 mg	PDP symptoms resolved by week 5	(ii) PDP may be mistaken for dementia
			(iii) Pimavanserin dosed at 17 mg/d may be effective in some patients
3	PIM 34 mg reduced to 17 mg for sedation	At PIM 17 mg, PDP symptoms resolved by week 4	(i) Pimavanserin may be added without disrupting or adversely affecting other multidrug PD regimens
4	PIM 34 mg	Reduction in PDP symptoms at 3 weeks and complete resolution of PDP and RBD symptoms at 6 weeks	(ii) Screening for psychosis may reveal PDP symptoms that might otherwise go unreported without elicitation by the clinician
5	Selegiline PIM 34 mg	Hallucinations continued with selegiline, although motor fluctuations improved; PIM resolved hallucinations	(iii) After an initial onset of symptoms, PDP may often progress in frequency and severity to require urgent treatment
6	PIM 34 mg	No response to pramipexole; after starting PIM, hallucinations improved
7	Escitalopram 10 mg PIM 34 mg Donepezil 10 mg	Hallucinations had resolved with 1-2 weeks of PIM; RBD symptoms persisted, so started clonazepam; DC escitalopram and added venlafaxine	(i) RBD, along with other parasomnias, is associated with visual hallucinations and cognitive impairment in patients with PD
			(ii) Concomitant RBD in a patient with PD reporting symptoms of possible psychosis requires assessment if the symptoms are related to RBD or to PDP
8	DBS initiated PIM 34 mg	Symptoms worsened after DBS; after starting PIM, symptoms improved	(i) Patients with PD who have DBS may be at increased risk of PDP
			(ii) Pimavanserin may be effective for treating PDP in patients with DBS
9	PIM 34 mg Quetiapine 150 mg	Discontinued amantadine and rotigotine; PDP partly resolved	(iii) Both pimavanserin and another antipsychotic may be necessary to manage PDP
10	Nonpharmacological; quetiapine 75–100 mg; PIM 34 mg	No response to nondrug intervention; marked improvement at 6 weeks
11	PIM 34 mg	After 4–6 weeks, marked improvement; no AEs	(i) PDP may emerge soon after PD diagnosis (e.g., within 1 year)
			(ii) PDP symptoms may be unrecognized in patients living in a nursing home or assisted living facility by the facility staff

AEs, adverse events; DBS, deep brain stimulation; DC, discontinued; PD, Parkinson's disease; PDP, Parkinson's disease psychosis; PIM, pimavanserin; RBD, rapid eye movement sleep behavior disorder. All cases constitute an AAN Class IV level of evidence and U level of recommendation.