Management of Psychosis in Parkinson’s Disease: Emphasizing Clinical Subtypes and Pathophysiological Mechanisms of the Condition

Abstract

Investigation into neuropsychiatric symptoms in Parkinson's disease (PD) is sparse and current drug development is mainly focused on the motor aspect of PD. The tight association of psychosis with an impaired quality of life in PD, together with an important underreporting of this comorbid condition, contributes to its actual insufficient assessment and management. Furthermore, the withdrawal from access to readily available treatment interventions is unacceptable and has an impact on PD prognosis. Despite its impact, to date no standardized guidelines to the adequate management of PD psychosis are available and they are therefore highly needed. Readily available knowledge on distinct clinical features as well as early biomarkers of psychosis in PD justifies the potential for its timely diagnosis and for early intervention strategies. Also, its specific characterisation opens up the possibility of further understanding the underlying pathophysiological mechanisms giving rise to more targeted therapeutic developments in the nearer future. A literature review on the most recent knowledge with special focus on specific clinical subtypes and pathophysiological mechanisms will not only contribute to an up to date practical approach of this condition for the health care providers, but furthermore open up new ideas for research in the near future.

Parkinson’s Disease Psychosis – Patterns of Care and Treatment in the EU-5 from Neurologists’ Perspective

“…4 Guidelines from European healthcare authorities that cover the management of PD include recommendations for managing the symptoms of PDP. These guidelines generally recommend withdrawal of add-on medications suspected to have triggered the symptoms of psychosis (e.g., anticholinergics, selegiline, amantadine) as the initial intervention.…”

G-CSF mediated neutrophil augmentation in a unique case of comorbid idiopathic Parkinson’s disease and treatment-resistant schizophrenia on clozapine

“…23,24 It has been further shown to be superior to other antipsychotics in controlling psychotic symptoms. 25 However, more recently, pimvanserin has emerged an effective treatment option for PD psychosis without motor function deterioration. 26 Clozapine therapy is limited by its potential to induce life-threatening agranulocytosis, requiring frequent blood monitoring, although relevant guidelines tend to differ between countries.…”

A Preliminary Investigation of the Views of People With Parkinson's (With and Without Psychosis) and Caregivers on Participating in Clinical Trials During the Covid-19 Pandemic: An Online Survey

“…In the early stages of PD, hallucinations typically occur with insight initially preserved, whereas in the later disease stages, patients might not recognize the hallucinations as unreal anymore due to the onset of false beliefs (delusions) ( 10 , 12 ). Given this progression, one might anticipate respondents with experience of delusions to have impaired insight compared to those with no experience of psychosis symptoms or experience of hallucinations only.…”

“…Their prevalence increases with illness duration, with most patients eventually developing such symptoms ( 11 ). Although there are a number of clinical options available for treating PDP, they are either not very effective or require specialized monitoring of side effects ( 12 ). It is vitally important that promising interventions continue to be tested in the form of a clinical trial.…”