To view this page ensure that Adobe Flash Player version 11.1.0 or greater is installed.
Parkinson’s Disease Psychosis—A Symptom Complex Signaling Risk for
Increased Disability and Caregiver Burden
Stuart H Isaacson, MD
Director, Parkinson’s Disease and Movement Disorders Center of Boca Raton, Boca Raton, Florida, US
Abstract Parkinson’s disease psychosis (PDP) occurs frequently in patients with Parkinson’s disease (PD) and involves a spectrum of symptoms, from mild
hallucinations to those that are more disruptive, as well as delusions, particularly around spousal infidelity and theft of money or possessions.
Risk factors for PDP include dopaminergic (and other) medications, cognitive disorders, sleep disorders, and duration of PD. Emerging evidence
suggests that PDP also reflects underlying PD pathology. Routine querying of major PDP symptoms can hasten recognition and allow earlier
diagnosis of PDP. Mild hallucinations with retained insight are frequent and may be tolerable by patients and caregivers, but symptoms that
can be considered as psychosis will typically increase in frequency and severity. Increasing PDP results in patient distress, increased caregiver
burden, and is a leading cause of long-term nursing home placement. PDP has also been associated with an increased risk for morbidity
and mortality. Ongoing research into the prevalence, risk factors, phenomenology, pathophysiology, and emerging pharmacotherapy for PDP
provides hope for improved diagnosis and management of PDP.
Keywords Parkinson’s disease, psychosis, evaluation, caregiver burden, quality of life
Disclosure: Stuart H Isaacson has received honoraria for consulting and research grants from ACADIA Pharmaceuticals Inc.
Acknowledgments: Editorial assistance was provided by Catherine Amey at Touch Medical Media, London.
Open Access: This article is published under the Creative Commons Attribution Noncommercial License, which permits any noncommercial use, distribution, adaptation, and
reproduction provided the original author(s) and source are given appropriate credit.
Received: February 13, 2015 Accepted: March 10, 2015 Citation: US Neurology, 2015;11(1):23–6
Correspondence: Stuart H Isaacson, MD, Parkinson’s Disease and Movement Disorders Center of Boca Raton, Boca Raton, Florida, US. E: isaacson@ParkinsonsCenter.org
Support: The publication of this article was supported by ACADIA Pharmaceuticals Inc. The views and opinions expressed are those of the author and not necessarily those of
ACADIA Pharmaceuticals Inc.
Parkinson’s disease (PD) is a progressive neurodegenerative synucleinopathy.
Clinical diagnosis is based on the presence of motor symptoms, including
bradykinesia, rigidity, rest tremor, and postural instability. 1 Although the
cause of PD is still unknown, the severe nigro-striatal dopamine loss
provides the basis for dopaminergic treatment of motor symptoms. Non-
motor symptoms are also prominent, probably reflecting more widespread
degenerative changes in PD, and include autonomic, enteric, and
neuropsychiatric symptoms. Neuropsychiatric symptoms can be
prominent, such as anxiety, depression, psychosis, sleep disturbances,
and cognitive impairment. 2,3 This has suggested to some that PD may be
accurately described as a neuropsychiatric disease rather than a pure
movement disorder. 3
This review aims to characterize Parkinson’s disease psychosis (PDP).
“Parkinson’s” and “psychosis” were used as search terms in a MedLine
review between the date limits of 1990 and 2014. When selecting papers
for inclusion in this review, priority was given to papers of higher
relevance (as determined by the MedLine database) and to more recently
Touc h MEd ica l MEdia
Prevalence and Incidence
The prevalence of hallucinations in PD in cross-sectional prospective
studies varies widely, from 16 % to 75 % (see Table 1). 4–7 In a Norwegian
population-based prevalence cohort study, 230 patients with PD
were followed up prospectively for 12 years. 8 The point prevalence of
PDP was 17.8 % (41/230) at baseline and increased to 48 % (12/25)
at the 12-year visit. Over the course of the study nearly two-thirds
of patients (60 %, 137 patients) had developed PDP during the
course of their disease. The incidence rate of PDP was 79.7 per 1,000
person-years. The variation in the reported prevalence of PDP may be due to differences
in study design and patient selection, as well as inconsistencies in
screening and patient or caregiver under-reporting. 7,9
• Patients may conceal their psychosis symptoms because of stigma
associated with psychiatric disease, and fear of psychiatric
hospitalization or long-term care placement.
• Caregivers may be unaware of mild symptoms.