Understanding the symptoms of Parkinson's disease psychosis

Psychosis is a condition where a person’s mind becomes disconnected from reality. As a result, a person may believe things that are not true, see or hear things that are not real, experience severely disorganized thoughts, and have changes in emotions and behavior.

While psychosis is often associated with severe mental health disorders (schizophrenia and bipolar disorder are two examples), it’s also associated with other types of conditions, including neurological disorders. One example is Parkinson’s disease (PD).

What is Parkinson’s disease?

Parkinson’s disease (PD) is a neurodegenerative disorder, a condition that causes the death of neurons in the brain. Neurons are nerve cells that enable communication between the nervous system and the rest of the body. As neurons are lost to disease, the brain loses the ability to communicate with different parts of the body.

With PD, this loss of neurons affects the parts of the brain that are responsible for movement. Tremors, muscle stiffness, loss of balance and mobility, slowed movement, and changes to posture and gait are the primary symptoms. However, PD causes a wide range of symptoms that can affect mental health, sleep, speech, swallowing, digestion, bladder control, vision, and many other aspects of a person’s health and well-being.

Psychosis symptoms are among the most common nonmotor symptoms associated with PD. As many as 40 percent of people with PD report symptoms of psychosis.

What are the symptoms of psychosis?

Psychosis symptoms can vary from one person to the next. As a person living with PD or a caregiver for someone with PD, it’s important to recognize how symptoms can manifest. Symptoms of Parkinson’s disease psychosis can include:

Hallucinations

A hallucination occurs when a person senses something that is not there. Hallucinations can involve sight, hearing, smell, touch, and taste. There are also presence hallucinations, where a person feels that something is nearby, such as a person standing just out of sight. Visual hallucinations are the most commonly reported symptom. Auditory hallucinations are also common.

Illusions

With an illusion, the eyes and brain misinterpret real objects in the environment. An example would be looking at a closet full of clothes and seeing a group of people. Illusions may progress into visual hallucinations over time.

Delusions

Delusions occur when a person believes something that is not based in reality. For example, paranoid thoughts about infidelity or people conspiring against you. Delusions are less common than hallucinations.

It should be noted that the psychosis symptoms associated with PD are typically different than the psychosis symptoms associated with mental health disorders, though there are similarities.

When can psychosis symptoms occur?

PD is a progressive condition—as more time goes on and more neurons are lost to the disease, symptoms become more severe and new symptoms appear. Some symptoms are more common during the advanced stages.

However, psychosis can occur at any stage of PD. Some people experience it in the more advanced stages. Other people experience psychosis in the early stages of the disease—in some cases, certain symptoms of psychosis may appear before motor symptoms. As with other symptoms of PD, psychosis symptoms can become more severe over time.

The link between PD and psychosis is not fully understood. It is believed to be a direct result of the damage to neurons caused by PD. Certain medications used to treat PD can also exacerbate psychosis symptoms.

If you or a loved one is living with Parkinson’s disease and experiencing symptoms of psychosis, talk to your healthcare provider. PD psychosis is associated with worse outcomes for people with Parkinson’s disease and greater distress for caregivers. Your healthcare provider can evaluate the symptoms and recommend a step-by-step treatment plan for helping manage symptoms.