• People with Parkinson’s disease may experience hallucinations and delusions caused by progression of the condition, medication side effects, infections, or other health conditions.

• If you or your loved one are experiencing hallucinations or delusions with Parkinson’s, work with your Parkinson’s specialist to find potential causes and manage these symptoms.

Between 20 percent and 40 percent of people living with Parkinson’s experience hallucinations or delusions at some point during the course of their disease. These symptoms can be challenging for people living with Parkinson’s — as well as their loved ones and caregivers.

Understanding the main causes of hallucinations and delusions in people with Parkinson’s can help you better recognize and cope with them. Read more about how medication side effects, progression of the disease itself, infections, and other health conditions may all play a role in causing hallucinations or delusions.

What Are Hallucinations and Delusions?

Hallucinations refer to sensing things that aren’t real. There are different types of hallucinations, including:

• Visual hallucinations (related to vision)
• Auditory hallucinations (related to hearing)
• Tactile hallucinations (related to touch)
• Olfactory hallucinations (related to smell)
• Gustatory hallucinations (related to taste)

Delusions, on the other hand, are irrational beliefs that are not based in reality. Delusions can lead to feelings of jealousy or paranoia or cause someone to believe they have special powers.

Both hallucinations and delusions are considered forms of psychosis, an assortment of symptoms of the mind that make it difficult for people to distinguish what’s real from what’s not real. Psychosis often starts with a person behaving in an out-of-character manner and could signal something’s wrong with them.

Read more about differences between hallucinations and delusions.

Knowing exactly what’s causing a hallucination or delusion isn’t always possible, understanding the potential causes can help people with PD work with their health care teams to determine appropriate treatment options to help improve quality of life.

Parkinson’s Disease Psychosis

Hallucinations and delusions are often symptoms of Parkinson’s disease psychosis (PDP), a neuropsychiatric condition that health experts believe to be caused by changes in brain chemicals and receptors. PDP involves a complex combination of neurological and psychological imbalances that affect both the central nervous system (CNS) and behavioral and mental functions.

Scientists suspect PDP is caused either by a Parkinson’s medication side effect or by Parkinson’s disease progression.

Dopamine Therapy and Psychosis

Parkinson’s causes neurons (nerve cells) that produce dopamine in the brain to die off. Dopamine is a chemical that regulates numerous functions in the body, including movement, cognition, behavior, memory, and mood.

The depletion of dopamine in people with Parkinson’s can cause a variety of symptoms that affect movement, motor functioning, and cognitive health. To treat these symptoms, people with PD are often prescribed dopamine therapy, which include dopamine agonist and dopaminergic drugs that stimulate neurons to produce dopamine or mimic dopamine function.

Neurological research has shown that hallucinations and delusions that occur with schizophrenia and other psychotic disorders may also be caused by a dysregulation of dopamine in which the brain produces too much of the chemical.

In people with Parkinson’s, dopamine therapy medications such as the combination of carbidopa and levodopa (Parcopa, Rytary, and Senemet) pose a risk of boosting dopamine levels too much. Increased levels of dopamine can cause unwanted side effects of severe behavioral changes, hallucinations, or delusions.

Other Parkinson’s medications that stimulate dopamine activity in the brain include amantadine and anticholinergic drugs. These medications are used to reduce motor symptoms and involuntary muscle movements and dyskinesia (spasms). However, researchers have linked PD psychosis to instances of dosages causing dopamine imbalances.

“I had several months of hallucinations, delusions, confusion, and severe imbalance all due to a medication I was taking for my dyskinesia. I am off of it now and doing much better,” a MyParkinsonsTeam member wrote.

“I had hallucinations years ago with amantadine but my doctor reduced the dosage and they stopped,” said another member.

One member described how they discovered their husband’s medication was causing hallucinations. “We drastically reduced amantadine (given for the dyskinesia) and his carbidopa and his hallucinations stopped. Work with your neurologist to make sure your meds are still right for you.”

Research also has linked pramipexole (Mirapex) — used to treat movement disorders in Parkinson’s — to hallucinations.

A member described a loved one’s experience with pramipexole. “He was on it for 10 years or so with no issues until the death of his wife,” they wrote. “After her passing he started having all kinds of increasing hallucinations and delusions. We took him off it, and within two weeks all hallucinations were gone.”

Medications for Other Conditions

Hallucinations can be a side effect of drugs used to treat other health conditions a person may develop alongside Parkinson’s. If you or a family member are experiencing hallucinations or delusions, it’s important to review all medications your or they are currently using. It’s possible that one drug in particular is causing the symptoms, or it could be a combination of medications. In some cases, depending on what condition is being treated, it may be necessary to change medications, dosages, or what times medications are taken.

Some types of medications — other than Parkinson’s treatments — that may cause visual hallucinations include:

• Antibiotics
• Blood pressure medication
• Antipsychotic drugs and other medications used to treat mood disorders

“My hallucinations were caused by my blood pressure medication. I just cut back on that, and problem solved,” a MyParkinsonsTeam member said.

Always get medical advice before stopping or changing a medication.

Psychosis and Parkinson’s Disease Progression

As Parkinson’s disease progresses, the rate of hallucinations and delusions increases. Neurology research indicates that hallucinations may be linked to cognitive impairment in Parkinson’s or Parkinson’s dementia, which include nonmotor symptoms such as:

• Memory problems
• Difficulty with decision-making
• Disturbances in visual-spatial perception
• Speech problems

There is a high prevalence of cognitive impairment in Parkinson’s disease. One study of 224 people living with Parkinson’s found that, over an eight-year period, around 78 percent developed some form of dementia.

A MyParkinsonsTeam member shared their husband’s experience. “My husband has PD dementia. He suffers from delusions and some paranoia,” they wrote. “The past week or so has been difficult. He believes the delusion so strongly that it keeps him stressed. At times he won't eat, and he is having trouble sleeping.”

Paranoid and persecutory delusions are common and disturbing forms of psychosis. Read more about ​​persecutory delusions, including examples.

Other issues, such as eye problems, light sensitivity, sleep disorders, and depression, are also common in people with Parkinson’s and can be associated with hallucinations and delusions.

Other Factors That May Cause Psychosis

Infections and conditions that can resemble Parkinson’s may cause psychotic symptoms. If you or someone you are caring for is experiencing hallucinations or delusions, your health care provider may want to test for other conditions.

Infections

Infections that are not tied to Parkinson’s disease can also cause psychosis with symptoms such as hallucinations and delusions in people with Parkinson’s. Urinary tract infections in particular are known to cause psychotic symptoms in older people.

One MyParkinsonsTeam member wrote, “I just woke up with a urinary tract infection accompanied by hallucinations.”

Pneumonia and other conditions that restrict oxygen, such as chronic obstructive pulmonary disease, can also cause psychotic symptoms in older people.

Alzheimer’s and Lewy Body Dementia

Alzheimer’s disease and Lewy body dementia are neurodegenerative conditions — conditions in which CNS cells stop functioning properly or die — that diminish brain function over time. This, in turn, can cause psychotic symptoms such as hallucinations and delusions. Alzheimer’s and Lewy body dementia usually affect older people and can occur with Parkinson’s disease. Cognitive and psychotic symptoms in both conditions can resemble Parkinson’s hallucinations or delusions.

Talk to Your Doctor About PD Hallucinations and Delusions

If you or a loved one are experiencing hallucinations or delusions, it’s important to discuss these symptoms thoroughly with a neurologist, particularly if these symptoms are worsening. The doctor can help with strategies for managing hallucinations and delusions.

Although treating symptoms of Parkinson’s psychosis can sometimes be challenging, your doctor can do tests and evaluations to better understand the root cause and determine treatment options.

Find Your Team

MyParkinsonsTeam is the social network for people with Parkinson’s disease and their loved ones. On MyParkinsonsTeam, more than 98,000 members come together to ask questions, give advice, and share their stories with others who understand life with Parkinson’s.

Have you and your doctor been able to pinpoint the cause of hallucinations or delusions? Has it helped to manage them? Share your experience in the comments below, or start a conversation by posting on your Activities page.