Hallucinations and Delusions in Parkinson's Disease

It might be surprising to learn that 20-40% of people with Parkinson’s disease (PD) will experience visual hallucinations. While typically not a symptom of PD itself, they can develop due to a change in PD medication or as a symptom of an unrelated infection or illness. Knowing the signs of hallucinations and how to manage them is important.   

Hallucinations and other more severe perceptual changes can be distressing to the family — often more so than to the person experiencing them. For the well-being of people with PD and caregivers, it is important to identify hallucinations as early as possible and take steps to reduce them.

The following article is based on a Parkinson’s Foundation Expert Briefing about hallucinations and delusions in Parkinson’s hosted by Christopher G. Goetz, MD, Professor of Neurological Sciences,  Professor of Pharmacology at Rush University Medical Center, a Parkinson’s Foundation Center of Excellence.

Hallucinations 101

Doctors often refer to hallucinations and other changes in perception as psychosis. While not every person with PD will develop psychosis or its symptoms, it can still be a frightening thought. 

A hallucination is a false perception. A person sees, hears, feels or perceives something that is not there. Among people with PD, visual hallucinations are most common, often of people or animals. They tend to be vivid and to happen at night. Usually they are not frightening and can become familiar. For example, a person might regularly hallucinate a puppy with a red collar.

A delusion is a fixed conviction that something is real when it is not. For example, Tom, who has PD and was previously a car dealer, was convinced that his house was a car dealership.

Paranoia is a delusion dominated by suspiciousness, fear and concern about safety. For example, a person may falsely accuse their partner of infidelity.

Among people with PD, these perceptual changes develop on a spectrum:

• Slight: illusions, misperceptions or hallucinations with no form, like a movement in the shadows. The person recognizes they are not real.
• Mild: formed hallucinations, where the person sees a child or small animal, like a cat. It looks real, but the person knows it is not.
• Moderate: formed hallucinations, such as a brother or person. There is a loss of insight and the person thinks the hallucination is real.
• Severe: these can be negative. For example, believing a stranger is trying to harm them or a loved one. Delusions can also be pleasant — the person might think they live in a garden or all-inclusive hotel.  

Given this range, delusions can easily infringe on quality of life. While experiencing a hallucination or delusion it is common for the person experiencing it to feel calm, but for family members to feel distressed.

A progression of these symptoms is consistent in Parkinson’s. It would be rare for a person with Parkinson’s to have delusions without hallucinations. However, if a person suddenly has delusions, an infection or other medical issue is likely the cause, and it’s important to see a doctor right away.

I'm experiencing hallucinations: what now?

Research has shown that for many people with PD who have them, hallucinations begin after a change in medication, more specifically, an increase in levodopa (also known as Sinemet). Additional factors make a person more likely to experience hallucinations when medications are changed, such as other cognitive problems or memory issues, depression and sleep problems.

Dementia is a term used to describe cognitive changes — whether in memory, judgment or attention — that interfere with daily life. It also increases the risk of hallucinations and delusions when PD medications are changed.

One thing that does not affect the risk of hallucinations is your regular dose of levodopa. Rather, studies show that a change in dose — an increase in a stable dose — can set off hallucinations.

Tip: Experiencing a hallucination does not mean you are “going crazy.” Many people recognize that their hallucinations are not real. Do not react or engage these visions or sounds — dismiss them. Bring up the topic with your doctor immediately.

People with Parkinson’s often ask, “Is my hallucination a one-time event?” A study sought to answer this by tracking 89 people with PD for 10 years. At the beginning, about a third experienced hallucinations. Over time, more participants experienced them. The study found that most people with PD who hallucinate will most likely continue to do so, and over time hallucinations can worsen. After 10 years, most of the participants experienced hallucinations.

Treatment Options

There are ways to manage hallucinations or delusions:

1. Rule out medical illness as a cause. The most common causes for sudden confusion and agitation are urinary tract infection or pneumonia. Did you recently start a new non-PD medication, like a bladder medicine or narcotic?
2. Review your prescriptions. Have they been filled correctly? Double check your dosages and pills.
3. Visit your regular doctor right away. If possible, try to avoid the emergency room. Your neurologist or PD doctor can offer medical approaches to reducing hallucinations. Under your doctor’s supervision, reducing the dose of your primary Parkinson’s medication may make hallucinations more manageable. However, it can be a trade-off — reducing medications can cause unsteady walking or an increase in tremor.
4. Talk to your doctor about eliminating nonessential medicines. Many medications complement the benefits of levodopa, but may not be necessary. These include anticholinergics (trihexyphenidyl, biperiden, Benadryl), amantadine and monoamine oxidase-B inhibitors (selegiline, rasagiline).
5. Your doctor may prescribe medication that targets hallucinations. Medications like clozapine or one that promote sleep can help you manage hallucinations. Therapies for dementia may improve cognition and the ability to cope with hallucinations. Talk with your doctor to find a treatment plan that works for you.

Tips for Caregivers

When a person with Parkinson’s develops hallucinations, immediately work with your physician and follow strategies at home to make the hallucinations manageable. Recognizing hallucinations — and dismissing them — are important ways of coping.

Hallucinations and psychosis are the aspects of PD that make at-home care most difficult. They are demoralizing, can disrupt sleep and fragment home life for the family. More than movement difficulties or any other aspect of PD, caregivers find hallucinations and delusions too much to cope with. 

Caring for someone who experiences hallucinations and delusions is a difficult job. Learn more in our book Psychosis: A Mind Guide to Parkinson’s Disease.

Call the Parkinson’s Foundation free Helpline at 1-800-4PD-INFO (1-800-473-4636) to talk to Helpline specialist.