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Professor of Neurology
Alzheimer's and Memory Disorders Division
Department of Neurology
Barrow Neurological Institute
Marwan Sabbagh, MD, FAAN: consultant/advisor/speaker: Alzheon, Biogen, Eisai, Genentech-Roche, KeifeRx, Lilly, NeuroTherapia, Novo Nordisk, Signant Health, Synaptogenix, T3D; ownership interest (stocks/stock options): Athira, Cortexyme/Quince Therapeutics, NeuroReserve, NeuroTau, Optimal Cognitive Health Company, Seq BioMarque, TransDermix, uMethod Health, Versanum; royalties or patent beneficiary: Humanix.
Parkinson’s disease psychosis (PDP) can be difficult to catch early due to lack of patient insight and anosognosia. Early treatment is key to improving patient outcomes, as psychosis can be a driver of morbidity and mortality. For that reason, healthcare professionals seeing patients with Parkinson’s disease should screen patients for presence of hallucinations or delusions at every visit—and these should be screened for as routinely as constipation, sleep problems, impulsivity, mobility, and balance. To help with screening, healthcare professionals can use a validated tool such as the Brief Psychiatric Rating Scale, Neuropsychiatric Inventory, or Scale for Assessment of Positive Symptoms adapted for Parkinson’s disease. By using a validated tool, measuring disease progression becomes easier and more standardized. In addition to routine screening, family members or caregivers should be present at appointments. Patients who lack insight into their disease are likely to underreport their symptoms, so that’s why family and caregivers should be present at appointments to provide information on the patient’s symptoms and functionality. If they can’t be present physically, I include them via telephone or video call.
Now, if screening for PDP indicates that a patient with Parkinson’s disease is experiencing hallucinations or delusions, the first thing I want to do is look for intercurrent illnesses. Specifically, I want to check for things such as infections, including urinary tract infections (UTIs), and metabolic problems. I also want to look deeper into their symptoms: Is it a sudden or a gradual onset? What triggers the hallucinations and delusions? How often are they occurring? Do they occur at a certain time of day?
If there appears to be a treatable cause, such as a UTI, the next thing to do is treat the UTI and observe if symptoms improve. If symptoms remain after an infection is corrected or ruled out, my next step is to try nonpharmacologic strategies. Lifestyle changes such as changing the lighting in their environment, reducing triggers, ensuring vision is optimized, and instructing family on interaction strategies can make a big difference in patient outcomes. Another option at this stage is to modify/simplify the patient’s antiparkinsonism medication regimen.
I recommend that patients try these strategies for a few weeks before progressing to pharmacologic options, but these symptoms of hallucinations, delusions, and sundowning tend to be very distressing to patients and caregivers, and therefore families may not want to spend much time on nonpharmacologic measures. There’s an urgency to what they want, so we might step up to do all of it at the same time. Because I don’t want to make too many changes at once, I will see patients with PDP rather often—approximately every 4-6 weeks. Lab tests are run at follow-up visits only if indicated.
When we’ve ruled out or corrected infections, metabolic problems, and other underlying causes of psychosis, as well as tried nonpharmacologic measures without success, that’s when I would start discussing pharmacologic treatment options. In the case of psychosis, the options are clozapine, quetiapine, or pimavanserin. Although all 3 of these agents have been investigated and shown to have some degree of efficacy in PDP, pimavanserin is the only one with FDA approval for treatment of hallucinations and delusions associated with PDP. Pimavanserin can take approximately 6-8 weeks to produce an effect, so emphasizing adherence and patience with the family and patient is key. Most of the time, adherence to treatment for PDP is not an issue because these patients are typically already being managed by somebody else. If the patient is trying to self-manage, then there is more of a risk for nonadherence. Again, I will see these patients approximately every 4-6 weeks to monitor their response to pharmacologic treatment.
Early identification and treatment initiation are key to improving outcomes for patients with PDP. Are you routinely screening your patients with Parkinson’s disease for PDP? Answer the poll below and provide your input in the comments section.