Hallucinations occur when a person sees, hears, feels, smells, or tastes something that doesn’t exist. Delusions are false, persistent beliefs, often about being harmed, deceived, or betrayed by someone else.

Between 20 percent and 40 percent of people with Parkinson’s disease report hallucinations or delusions. When these symptoms occur with Parkinson’s, they’re known as Parkinson’s disease psychosis.

Identifying hallucinations and delusions can sometimes be challenging for those experiencing them — and for their caregivers and loved ones. Keep reading for tips on how to identify hallucinations and delusions that may occur with Parkinson’s.

People May Realize Their Hallucinations Aren’t Real

People may be aware that they are experiencing a hallucination while it’s happening or realize it shortly after. This is called retaining insight.

Losing insight or failing to realize something is a hallucination can cause agitation and increase the risk of injury to the person or others.

Delusions Involve False Beliefs Not Based in Reality

The Parkinson’s Foundation describes delusions as “illogical, irrational” and “persistent thoughts not based in reality.” They are less common than hallucinations. About 8 percent of people with Parkinson’s disease experience delusions.

Delusions can be particularly challenging for family members and caregivers because a person with Parkinson’s may falsely believe someone is harming them.

Seeing Things Is a Common Type of Hallucination

Visual hallucinations are the most common type of hallucination in Parkinson’s psychosis.

Visual hallucinations often involve animals or people, such as a child or deceased family member. People often experience hallucinations in their peripheral vision and in low-light or low-visibility situations.

Members of MyParkinsonsTeam share examples of their visual hallucinations:

“I started having hallucinations a few nights ago. There was a cat crawling around the living room and climbing on furniture.”

“I see the random cat or rabbit pop out when walking through the house. I momentarily thought there was someone in my yard.”

“When I’m sitting at my desk, I wear glasses, and in my peripheral vision to the left side of my head, I see people standing next to me as I am seated. It’s not the same person. It could be a teenage boy or an adult woman.”

A Person May Hallucinate Hearing Distant Sounds

Auditory hallucinations occur when a person hears a sound that isn’t actually there. They happen less frequently than visual hallucinations.

MyParkinsonsTeam members share examples of auditory hallucinations:

“My husband had an auditory hallucination last night for the first time. He got into his wheelchair and went looking for water that he ‘heard’ running.”

“I kept hearing a faint repetitive alarm in my head, just like my alarm. Checked the cell phone alarm to make sure I had turned it off.”

“Hearing a radio, TV, or something and absolutely KNOW there is nothing on? This is almost a constant thing for me. The upside for me is it’s music, although it’s hard to make out the tunes most of the time.”

Hallucinations May Involve Other Senses as Well

People with Parkinson’s disease can also experience olfactory (smell), tactile (touch), and gustatory (taste) hallucinations. These types of hallucinations are less common than visual and auditory hallucinations.

Smelling cigarette smoke is an olfactory hallucination several members of MyParkinsonsTeam describe:

“I have, over the past few months, been having the issue of smelling smoke occasionally when there is none. It’s subtle and will last for about an hour.”

“I can smell cigarette smoke. I smelled it all day today, and there is no one anywhere who smokes.”

“It’s nice to hear I’m not alone in this. It’s just my hubby and me, and neither of us smokes, nor does anyone we know, unless my cat is secretly lighting one up without my knowledge. LOL!”

Early Hallucinations Can Occur With Lewy Body Dementia

Visual hallucinations that occur early in the course of dementia are a common feature of dementia with Lewy bodies.

Telling the difference between Parkinson’s dementia and Lewy body dementia can be challenging because of overlapping symptoms, including motor symptoms, visual hallucinations, and delusions.

The main difference between the two conditions is when symptoms develop. If dementia symptoms (changes in thinking and memory) appear first or within a year of movement symptoms such as tremors or slow movements, the diagnosis is more likely to be dementia with Lewy bodies.

Believing You’re Being Mistreated Is a Common Delusion

Delusions often focus on a person’s belief they’re being mistreated. As a result, people experience paranoia, mistrust, anger, and anxiety. Two common types of delusions are jealousy and persecutory delusions:

These types of delusions can be very difficult to handle because they can lead to aggressive or unsafe behaviors that put both the person with Parkinson’s and their caregivers at risk.

Caregivers on MyParkinsonsTeam share their experiences with jealousy and persecutory delusions:

“My husband still thinks I’m slipping out at night, which I understand is the number one delusion for a spouse!”

“He is saying I am lying to him, and he is showing signs of being paranoid.”

“My husband believes men are after him. He can become distrustful of me and his healthcare aide, whom he likes very much. These bad episodes can last one hour or six hours.”

“My mom tells me I don’t feed her or I make her eat things that she doesn’t like.”

Delusions May Lead to Anxiety or Agitated Behavior

A person experiencing delusions may be anxious or fearful and may become very agitated.

Caregivers explain how delusions affect their loved ones’ behavior:

“He believes the delusion so strongly that it keeps him stressed. At times he won’t eat, and he is having trouble sleeping.”

“She gets agitated, asks where she is, and sometimes has intense moments of confusion and fear.”

“My man friend, age 92, gets feisty and argumentative. It is extremely hard for me to keep a civil tongue. He’s angry even when you accept his version of reality.”

Hallucinations and Delusions May Both Pose Dangers

Keep in mind that both hallucinations and delusions can be dangerous if you or your loved one acts on them. “I acted out on many of my hallucinations,” one MyParkinsonsTeam member wrote. “One time I fell forward, flat on my face, in an intersection!”

Delusions can occur alongside dementia. Dementia can cause confusion and changes in judgment or behavior that may be unsafe.

A MyParkinsonsTeam member who cares for a parent described this experience: “I have to take things away because she plays with things that can be dangerous. She tries putting things in outlets that don’t belong.”

Managing Hallucinations and Delusions

Managing hallucinations and delusions may involve making changes to Parkinson’s medications, addressing underlying health conditions, such as infections or other acute illnesses, and making household changes to keep your loved one safe.

A neurologist or psychiatrist may recommend stopping certain medications, adjusting dosages, or adding a new medication to treat Parkinson’s psychosis. Talking openly with your loved one’s healthcare provider about these symptoms is the first step in finding effective treatment options.