Parkinson's Disease Psychosis: Review of Neuropsychiatric Complications

Program Introduction

An average of 35% of patients diagnosed with Parkinson’s disease experience Parkinson’s psychosis. Recognition and diagnosis of this nonmotor manifestation is critical in choosing the best treatment strategy and managing these symptoms.  

Learning Objectives

After completing this educational activity, you should be able to: 

  • Identify appropriate best practices for the diagnosis of PDP 
  • Implement evidence-based current therapies for patients with PDP 

Target Audience

Neurologists, psychiatrists, gerontologists, primary care clinicians, nurses, nurse practitioners, physician’s assistants, pharmacists, and other health care professionals. 

Program Description

Parkinson’s disease (PD) affects approximately 1% of the population aged 60 years and older and has the fastest rising prevalence of all neurodegenerative diseases worldwide. PD is characterized by bradykinesia plus rigidity, resting tremor, and/or postural instability. Other motor features can include shuffling gate, microphagia, muscle contraction, and slurred or slowed speech, among others. PD can also manifest nonmotor symptoms, such as sleep disturbance, loss of smell, and autonomic symptoms like excessive sweating, sexual dysfunction, and drooling. Parkinson’s disease psychosis (PDP) is also a nonmotor symptom and manifests an average of 35% of patients diagnosed with PD. 

To diagnose PDP a primary diagnosis of PD must be made. First, Parkinsonism must be established, which is characterized by bradykinesia plus 1 or more features of rest tremor and/or rigidity. PD is then diagnosed by the absence of exclusion criteria, the presence of at least 2 supportive criteria, and no red flags. Symptoms of PDP include hallucinations, illusions, delusions, and a false sense of presence, which occur after the onset of PD and are recurrent or last for at least a month.  

Once a diagnosis is made, treatment can include evaluating triggers, stopping non-PD drugs or anticholinergics, MAOB inhibitors, or others, and considering PDP therapies clozapine, quetiapine, and pimavanserin. An interdisciplinary approach to treatment management that includes psychiatrists, psychologists, and physical and occupational therapists can optimize patient outcomes. 

Educating patients and family members about symptoms and discussing treatment goals is key in helping to improve quality of life for both patients and caregivers. 

Activity summary
Available credit: 
  • 0.50 AMA PRA Category 1 Credit™
  • 0.50 Participation
Activity opens: 
Activity expires: 

Support Statement

Supported by an educational grant from Acadia Pharmaceuticals Inc. 

Learning Objective

After completing this educational activity, you should be able to: 

  • Identify appropriate best practices for the diagnosis of PDP  
  • Implement evidence-based current therapies for patients with PDP 

Release, Review, and Expiration Dates

This CME activity was published in February 2023 and is eligible for AMA PRA Category 1 Credit™ through February 29, 2024.

Statement of Need and Purpose

Clinicians need education about best practices for the recognition and diagnosis of PDP and about current strategies for the management of PDP and their impact on quality of life.  The most recent diagnostic criteria for Parkinson's Disease recognize the frequency with which patients experience nonmotor symptoms and include the absence of any nonmotor symptoms within five years of disease onset as a red flag suggesting an alternative diagnosis. Clinicians must be aware of the potential nonmotor symptoms patients with Parkinson's Disease may experience and should assess for them at diagnosis and throughout the disease.  Although there are no standardized diagnostic criteria for PDP, provisional criteria were proposed by the National Institutes of Neurological Disorders and Stroke and the National Institute of Mental Health.  The use of standardized screening tools can aid in identifying nonmotor symptoms, including neuropsychiatric symptoms associated with PDP.   

Clinicians should approach patients with Parkinson’s Disease who experience psychosis by initially assessing for the presence of any triggers that may be addressed. If diagnosed, PDP should be managed with education, support, and behavioral strategies. Patients should be educated early about potential nonmotor symptoms such as PDP so they may report symptoms to allow for early interventions. An initial strategy in addressing PDP is to reduce or remove medications that may worsen psychosis, starting with non-Parkinson’s Disease medications such as anticholinergics, benzodiazepines, and opioids, before changing medications for Parkinson’s Disease.   Antipsychotics are generally avoided in Parkinson’s Disease because their excessive dopamine blockade can worsen motor symptoms, worsening quality of life. Three antipsychotics, clozapine, quetiapine, and pimavanserin, may be used in Parkinson’s Disease without worsening motor symptoms.  

Optimal management of Parkinson's Disease requires a collaborative, multidisciplinary approach.  Real-time communication between specialists is essential to ensure all care team members are aware of changes in drug therapy regimens that may impact other aspects of Parkinson's Disease care. Multidisciplinary collaboration is crucial when considering neuropsychiatric symptoms of Parkinson's Disease, such as PDP, which may be associated with medications used to treat other symptoms or may be caused by pre-existing psychiatric illness or Parkinson's Disease itself. Coordinated multidisciplinary centers with specialized inpatient and outpatient services for Parkinson's Disease may meet the needs of patients with Parkinson’s Disease with neuropsychiatric symptoms by incorporating specialists from neurology, neuropsychiatry, neuropsychology, and functional neurosurgery as well as nurse coordinators and allied health professionals.  

Unlabeled and Investigational Usage

The faculty of this educational activity may include discussions of products or devices that are not currently labeled for use by the FDA. Faculty members have been advised to disclose to the audience any reference to an unlabeled or investigational use.

No endorsement of unapproved products or uses is made or implied by coverage of these products or uses.

Please refer to the official prescribing information for each product for discussion of approved indicators, contraindications and warnings.

Review Process

The faculty members agreed to provide a balanced and evidence-based presentation and discussed the topics and CME objectives during the planning sessions. The faculty’s submitted content was validated by CME Institute staff, and the activity was evaluated for accuracy, use of evidence, and fair balance by the Chair and a peer reviewer who is without conflict of interest.  

The opinions expressed herein are those of the faculty and do not necessarily reflect the opinions of the CME provider and publisher or the commercial supporter 

© Copyright 2023 Physicians Postgraduate Press, Inc.

Faculty Affiliation

Photo of Michael Okun
Michael Okun, MD 
Department of Neurology 
University of Florida College of Medicine 
Gainesville, Florida  

Photo of Emily Henderson
Emily Henderson, MBChB,

University of Bristol 
Bristol, UK

Photo of Pamela Zeilman
Pamela Zeilman, APRN 
Department of Neurology 
University of Florida College of Medicine 
Gainesville, Florida  

Financial Disclosure

The CME Institute adheres to the Standards for Integrity and Independence in Accredited Continuing Education of the Accreditation Council for Continuing Medical Education (ACCME). Any individuals in a position to control the content of a continuing education activity, including faculty, content developers, reviewers, staff, and others, are required to disclose to learners the presence or absence of any relevant financial relationships with an ACCME-defined ineligible company within the preceding 24 months of the activity. The ACCME defines an “ineligible company” as one whose primary business is producing, marketing, selling, re-selling, or distributing healthcare products used by or on patients. 

The CME Institute has mitigated all relevant conflicts of interest prior to the commencement of the activity. None of the individuals involved in the content have relevant financial relationships with ineligible companies except the following: 

Dr. Okun has no financial disclosures. 

Dr. Henderson has received consulting fees from Abbvie and Bial; has received grant/research support from The Gatsby Foundation, National Institute of Health Research Health Technology Assessment, Elizabeth Blackwell Institute Health Data Strand, Engineering and Physical Sciences Research Council (EPSRC) Impact Acceleration Account, NIHR Research for Patient Benefit (RfPB) Programme, Alzheimer’s UK Pump Priming Award, and British Geriatrics Society; has received honoraria for speaking/teaching from Kyowa Kirin, Abbvie, and Bial; has served on the advisory board for Abbvie; and received travel support from Bial.   

Pamela Zeilman, MSN, has no financial disclosures.    

Michael R. Page, PharmD, RPh 
Independent Medical Director/Medical Writer 
Plainsboro, New Jersey 

Dr. Page is a consultant for BioCentric, Inc. and American Medical Communications, Inc. 

None of the other planners, reviewers, and CME Institute staff for this educational activity have relevant financial relationships with ineligible companies to disclose. All relevant financial relationships have been mitigated. 

Accreditation Statement

The CME Institute of Physicians Postgraduate Press, Inc., is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

Credit Designation

The CME Institute of Physicians Postgraduate Press, Inc., designates this enduring material for a maximum of 0.50 AMA PRA Category 1 Credit™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Note: The American Nurses Credentialing Center (ANCC) and the American Academy of Physician Assistants (AAPA) accept certificates of participation for educational activities certified for AMA PRA Category 1 Credit™ from organizations accredited by the ACCME.

To obtain credit for this activity, study the material and complete the CME Posttest and Evaluation.

Available Credit

  • 0.50 AMA PRA Category 1 Credit™
  • 0.50 Participation


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