Fast Facts: Psychosis in Parkinson's Disease: Finding the right therapeutic balance

By J.H. Friedman and C. Ballard

Psychosis affects nearly 50% of patients with Parkinson’s disease (PD). It is a major therapeutic challenge, as a balance needs to be found between the PD medications that can exacerbate psychotic symptoms and the antipsychotics that may worsen motor function. Focusing on the most common side effects of PD medications, namely visual hallucinations and delusions, this highly readable handbook will increase readers’ awareness of: • the various presentations of psychosis in PD • modifiable risk factors • prescribing that balances the benefits and potential harms. Detailed case studies and evidence-based guidance for practical application make 'Fast Facts: Psychosis in Parkinson’s Disease' an invaluable resource for all healthcare professionals responsible for the outpatient care of patients with PD, including neurologists, psychiatrists, geriatricians, psychiatric nurse practitioners, specialist PD nurses and primary care providers.

• Language: English
• Publisher: S. Karger
• Release date: May 7, 2019
• ISBN: 9781912776283

Book preview

Introduction

Psychosis is a common neuropsychiatric complication of Parkinson’s disease (PD) that affects nearly 50% of patients over the course of the disease. It is a major therapeutic challenge. Although Parkinson’s disease psychosis (PDP) can be induced by PD therapy, spontaneous emergence may also occur. Visual hallucinations (usually mild) and passage phenomena may occur relatively early in the disease. Severe hallucinations, delusions and delusional misidentification are more common in later stages of the disease and in the context of PD dementia or dementia with Lewy bodies.

In our experience, healthcare professionals, including neurologists, consider PD to be a movement disorder – which it is – but they are less aware of the many ways in which PD affects the patient and their caregivers and family, especially the non-motor behavioral aspects of the disease. Sleep disorders that turn out to have been herald features of the disease (e.g. rapid eye movement sleep behavior disorder) often pre-date any motor symptoms or signs by several years.¹ In addition, anxiety and depression, which affect about half the PD population, are now thought to be physiological responses to neuropathology and not only emotional responses to the diagnosis and the physical limitations it causes.²

Here, we focus on psychotic symptoms, primarily hallucinations and delusions. Psychotic symptoms are the result of particular interactions between the medications given to patients with PD and PD pathology. Patients and their family members are often reluctant to discuss these symptoms and must be asked about them. Behavioral problems in PD, particularly hallucinations and delusions, tend to cause more stress for caregivers than motor dysfunction does, leading to higher rates of institutionalization.

This resource is for all healthcare professionals responsible for outpatient care, including neurologists, psychiatrists, geriatricians, psychiatric nurse practitioners, specialist nurses and primary care providers. It will help readers avoid problems by inquiring before they develop and recognizing the risk factors, while increasing awareness of how PDP presents and how to manage it.

References

1. Galbiati A, Verga L, Giora E et al. The risk of neurodegeneration in REM sleep behavior disorder: a systematic review and meta-analysis of longitudinal studies. Sleep Med Rev 2018;43:37–46.

2. Weintraub D, Burn DJ. Parkinson’s disease: the quintessential neuropsychiatric disorder. Mov Disord 2011;26:1022–31.

Definitions

Psychosis. The definition of psychosis has changed in recent years. Until publication of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), psychosis was deemed a loss of reality testing. When patients could not reliably distinguish what was real from what was imagined, they were thought to be psychotic. While DSM-5 defines psychotic symptoms and psychotic syndromes,¹ there is no specific description for Parkinson’s disease psychosis (PDP). The only proposed definition of PDP is in a report from a combined National Institutes of Health (NIH) and Food and Drug Administration (FDA) ad hoc committee.² The tenth edition of the International Statistical Classification of Disease and Related Health Problems (ICD-10) has two general classifications: psychiatric disorder with delusions (F06.2) or hallucinations (F06.0) due to known physiological condition.³

PDP was defined by the NIH-FDA committee as a syndrome in which the patient with PD experiences hallucinations or delusions intermittently or continuously for 1 month or more. The hallucinations may be very transient or continuously present. The syndrome is further subtyped as PDP with or without insight and with or without dementia. Psychotic symptoms in the setting of delirium fall into a less well-defined category.

Illusions are almost always visual misperceptions, such as mistaking a pillow in the shadows as a small cat. Normal people experience illusions, usually those who need but don’t have glasses. However, they occur to a much greater degree and with a greater sense of reality in people with PD. For example, a fire hydrant at a distance is thought to be a boy walking a dog; a tree is thought to have people playing on the branches. When the image is seen at closer range the misperceptions resolve and the patients are fully aware of their mistake.

Hallucinations are perceptions in one of the five sensory modalities of vision, hearing, touch, smell or taste, even though there is no actual stimulus. Visual hallucinations are the most common (Figure 1.1). Other sensory hallucinations (e.g. auditory) are less common but do occur, sometimes in conjunction with visual hallucinations. Classic hallucinatory symptoms of schizophrenia, such as third-party auditory hallucinations or auditory hallucinations in the form of a running commentary, are very uncommon in people with PD. Visual hallucinations are usually more persistent and intense in people with Parkinson’s disease dementia (PDD) or dementia with Lewy bodies (DLB).

The hallucinations in PDP are often categorized as major or minor.²

Minor hallucinations are ‘passage’ or ‘presence’ hallucinations. They are rarely upsetting to patients.

Passage hallucinations are those that occur when patients see things in their peripheral visual field, usually shadows of passing figures, small animals or people, but when they turn to look, the figures disappear. Sometimes patients see reflections off their eyeglasses, as if there is a light behind them, but when they turn there is nothing there.

Figure 1.1 Drawing made by a patient to describe his hallucinations of the people he saw in a house plant. He described a family who he felt he needed to keep an eye on to prevent them from doing something untoward. He drew an image of the father, who was hiding ‘in the weeds’.

Presence hallucinations are not really hallucinations, as they are not perceived stimuli but rather a feeling that there is someone, or less commonly an animal, behind them or to the side out of view. When the patient turns, there is nothing there. The feeling that someone is behind them virtually never causes any degree of concern or distress. The presence is almost always perceived as benign.

Major hallucinations are generally distinct.² Patients may see, feel or hear things as if they are present, sometimes for seconds, sometimes for hours but usually lasting minutes. Although they are always transient, they last long enough to be perceived clearly and often recur frequently.

Delusions are false, irrational beliefs that are not based on reality. Unlike hallucinations, which are usually without emotional associations, delusions tend to be paranoid in nature. Delusions of spousal infidelity, categorized as ‘jealous delusions’, are common. Since the basis for the belief is not rational, patients cannot be reasoned with. Overall, delusions are less common than hallucinations, particularly in the early stages of PD.⁴ First-rank symptoms of schizophrenia (i.e. symptoms that are highly suggestive of schizophrenia),