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Symptoms - Psychotic Symptoms

Written by: Emily Downward | Last reviewed: March 2017 | Last updated: September 2022

More than half of all people with Parkinson’s disease (PD) will develop psychotic symptoms. The most common psychotic symptoms seen in people with PD are hallucinations and delusions.

Impact on quality of life

Psychotic symptoms greatly affect the quality of life for both patients and caregivers. Psychotic symptoms are associated with an increased incidence of nursing home placement, as caregivers are unable to cope with the hallucinations and delusions.

Psychotic symptoms are also associated with a higher risk of dementia and increased risk of death. Generally, psychotic symptoms develop several years after a diagnosis of PD.

Because these symptoms are related to both psychiatry (the area of medicine focused on mental and behavioral health) and neurology (the area of medicine focused on the nervous system), psychosis with PD is considered a neuropsychiatric condition.1,2

What are hallucinations?

Hallucinations are seeing, hearing, or feeling something that is not actually there. Most hallucinations experienced in PD are visual, although some people experience auditory, tactile (touch), or olfactory (smell) hallucinations.

Hallucinations occur when the person is awake—not sleeping or dreaming—and can occur at any time of day or night. They can be frightening, for the patient experiencing them as well as their caregiver. Generally, hallucinations are repetitive and last for a short duration.1,3

What are delusions?

Delusions are irrational, illogical views that are not based on reality. They usually involve jealousy, persecution, and/or abandonment. To the person experiencing delusions, they seem very real and cannot be controlled.

A common type of delusion is paranoia, in which a person becomes highly suspicious. Delusions and paranoia may make the person with PD afraid of being poisoned by medications or food. A person experiencing delusions may also accuse their loved ones of trying to harm them. They may become argumentative, aggressive, or unsafe.1,3

What is agitation?

Agitation is a state of high anxiety, extreme restlessness, or excitement. Agitation may be a sign of psychosis in patients with PD, although it can also be associated with depression or anxiety, other non-motor symptoms of PD. Agitation is also used to describe restless motor symptoms of PD.4,5

What causes psychotic symptoms?

Psychotic symptoms in people with PD are usually caused as a side effect of medications used to treat PD.

All of the current PD medications can potentially cause psychotic symptoms. Hallucinations and delusions may also be caused by the chemical and physical changes that occur in the brain as a result of PD. 3

Talk to your doctor

Any psychotic symptoms, such as hallucinations, delusions, or paranoia, that are experienced by a person with PD should be reported to a doctor, even if the symptoms are not bothersome.

Managing these symptoms may include reducing or withdrawing the use of PD medications that may be causing the symptoms or adding an antipsychotic medication.1,2

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