“Parkinson’s Disease Psychosis: The What, When, Why and How” – Webinar Notes

“Parkinson’s Disease Psychosis: The What, When, Why and How” – Webinar Notes

The Davis Phinney Foundation for Parkinson’s hosted neurologist Christopher Goetz, MD in a webinar about “Parkinson’s Disease Psychosis: The What, When, Why and How.”  Though the webinar was back in August 2020, we at Stanford Parkinson’s Community Outreach listened to the webinar and are sharing our notes. 

Parkinson’s disease psychosis is where people experience hallucinations or delusions. Hallucinations are seeing things that don’t exist. They can also be in the form of tactile hallucinations where one can feel a presence that isn’t there, or olfactory hallucinations where someone smells something that isn’t there. In comparison, illusions are a misinterpretation of something that is there, such as believing that a lamp in a corner is actually a person. Psychosis  is a psychiatric term used in neurology to refer to a spectrum of abnormalities. The strongest feature is visual hallucinations. Dr. Goetz’s talk focused on hallucinations, and he spent little time on delusions. 

Progression of disease or medication are the two greatest causes of hallucinations. 

The link to the webinar can be found on the David Phinney YouTube channel

Stanford Parkinson’s Community Outreach has a webpage with resources on hallucinations and delusions.

See extensive notes on the August  27th webinar below.


– Joëlle Kuehn

“Parkinson’s Disease Psychosis: The What, When, Why and How”

Speaker: Dr. Christopher Goetz,Rush University Medical Center, Chicago.

Webinar Host: Davis Phinney Foundation for Parkinson’s

Webinar Date: August 27, 2020 

Summary by Joëlle Kuehn, Stanford Parkinson’s Community Outreach

Interesting facts about hallucinations:

  • Approximately 50% of all people living with Parkinson’s will experience some form of hallucinations. 
  • The longer one lives with Parkinson’s, the greater the likelihood they’ll experience hallucinations.. 
  • At the beginning of the disease hallucinations are very uncommon. If one experiences hallucinations in the early stages (first year) with no medication, it could be a misdiagnosis. 
  • After 10 years, around 60% of patients have some form of hallucinations.

Psychosis – psychiatric term used in neurology to refer to a spectrum of abnormalities. The strongest feature is visual hallucinations. Hallucinations are false perceptions of reality. The patients are wide awake and generally see something that isn’t there. It can progress to a delusion, which is a false belief (ex. If children are in the house, the patient may think they are in a daycare center, or a zoo). 

When hallucinations start, it is a sign that doctors need to be cautious with medications and the state of the disease. Unlike most aspects of Parkinson’s disease, doctors cannot see it. 


  • Visual hallucinations: most common kind, see things that don’t exist
  • Tactile hallucinations: feeling that someone is standing behind you that isn’t there (sense of presence – don’t see anything but know that they are there)
  • Olfactory: smell things that aren’t there
  • Auditory: uncommon (more common in schizophrenia) 


  • Separate from hallucinations
  • A misinterpretation of something that is there
  • Ex. A person might see a standing lamp in a corner as a person standing there. The stimulus is a lamp, misinterpretation is a man. Happens more often in the evening where lighting and shadows are common.

Some questions that are asked to test severity of hallucinations:

  • Well-formed or vague?
  • Illusions or true hallucinations?
  • Is insight retained or lost (if insight is lost you cannot suppress hallucinations anymore because they do not recognize they are hallucinations)?
  • Is there delusional thinking?

Once you develop the symptom of hallucinations, it will not go away, although the severity might change. Progression of disease or medication are the two largest causes of hallucinations.  Dopamine medications can create hallucinations. The dose of medication you are on does not necessarily define when hallucinations will happen. Lowering dopamine drugs will help hallucinations. The doctor will look at whether any medications are optional. Commonly, if a patient has a second diagnosis (urinary tract infection, pneumonia etc.), and is being treated for that with medication, it could create hallucinations as well. 

Hallucinations are hard to diagnose because they are promoted by a quiet understimulated environment, which is not a doctor’s office or under a scanner. Normal visual stimuli stay in the visual part of the brain. Hallucinations have the same input but the information goes to the frontal part of the brain.

We don’t have evidence that can predict that people will become hallucinators based on brain scans, so it is difficult to start treating prophylactically. 

There are strategies to try to keep the hallucinations quiet. 

If you are having delusions, you need a doctor and treatment because it is not fair because that person is suffering due to a loss of sense of reality. 

Overlap with sleep abnormalities and hallucinations: 

  • There is a great overlap with sleep abnormalities and hallucinations.
  •  If you can get a person to sleep, hallucinations improve. 
  • Sleep deprivation is bad for hallucinations.
  •  A drug commonly used to treat hallucinations is quetiapine. It is a sleep aid. It isn’t approved for hallucinations and clinical trials have not shown to be successful for hallucinations but it is still widely used because it puts people to sleep and they sleep and are more alert and cooperative and cognizant when awake. This allows them to suppress hallucinations because of more insight they have.

Question and Answer Session (questions from the moderator, Dr. Soania Mathur): 

Question: A big question from caregivers and families is should I let them be during hallucinations and not correct them because it is potentially demeaning?

Answer:  It is not safe to play into it (we don’t pretend you didn’t fall, so we shouldn’t pretend that you are not having a hallucination). Do not allow the loss of insight to take ground. Some ways to help prevent is to keep lights on, or have extra stimulation such as music. 

Question:  How do you de-escalate if a person gets agitated during a hallucination?

Answer:  It is best to step back and not engage if correcting will make a person more angry. Do not enter into the dialogue and play into it, but simply step back. The doctor needs to be involved in this. 

Question:  Is there any relationship with REM sleep behavior disorder?

Answer:  No. REM behavior disorder and abnormalities of sleep are common in Parkinson’s disease and REM behavior often precedes behavior of Parkinson’s disease, but those are sleep disorders and hallucinations are not nightmares. They are an awake phenomenon and are not sleep events. They are stereotypic repetitive visions. It is not random. 

Question: Are medications – Parkinson’s or otherwise – associated with hallucinations or delusions?

Answer:  The dopaminergic drugs are associated with hallucinations. Many drugs that are used to treat Parkinson’s can cause and aggravate hallucinations. Some are particular: 

  • Amantadine in a daytime medication, if it is taken at night it can cause hallucinations.
  • Anticholinergic drugs: not used as much anymore but have a high propensity to induce delirium and can precipitate hallucinations and agitations.
  • Sometimes drugs that are used for urinary incontinence are prescribed to go to the bladder, but can go to the brain and cause hallucinations. 

Question:  You mentioned quetiapine is common to treat psychosis, what other medications are commonly used?

Answer:  A lot of medication that treats psychosis block dopamine, but we need to augment dopamine to treat Parkinson’s. There are many agents that can stop or improve hallucinations, but they make Parkinson’s worse. One effective agent that has been used is called clozapine and requires medication monitoring and bloodwork to. There is one drug to specifically treat hallucinations in Parkinson’s disease called pimavanserin and is very effective but takes a few weeks to work. 

Question: At what point should patients or their caregivers come see you? 

Answer: I ask about hallucinations at every appointment, but there is no appointment made because of hallucinations, and you have to have them in order to talk about them. It is important to talk about it when it starts happening. 

Viewers Question and Answer:

Question: Is Parkinson’s psychosis the same as Lewy Body Dementia (LBD)?

Answer: No. They have the same import, the hallucinations are similar in that they’re visual. But LBD starts with cognitive problems, often with hallucinations and delusions are an early problem and more of an issue than hallucinations. For Parkinson’s, delusions are at the end, but for LBD delusional thinking are very common. The time frame is quite different. 

Question: You mentioned that amantadine being taken at night is an issue. What about Gocovri which is given at night?

Answer: Gocovri is a brand name for a protein-bound form of amantadine so it is very slowly secreted. The long acting forms are not included in my statement that amantadine cannot be used at night. 

Question: Do antidepressants increase the risk of hallucinations?

Answer: No.

Question: What is the effect of anxiety on hallucinations?

Answer: There’s no pattern that says anxiety leads to hallucinations. Some people are calm and aren’t bothered by it. Treating anxiety will not stop hallucinations because it is a separate issue. 

Question: Does deep brain stimulation (DBS) change the frequency or occurrence of hallucinations?

Answer: Most centers would not take a patient to DBS who has active hallucinations. The issue is that you are putting electrodes into the brain and we don’t like to do that with people with psychiatric issues because it might play into the problems. It is an exclusionary criteria for DBS.

Question: Is there any distinction between Young Onset Parkinson’s Disease (YOPD) versus older onset of Parkinson’s as far as susceptibility to hallucinations?

Answer: Age and duration of disease are two factors associated with hallucinations. Most young onset patients will still be young. But there are young onset patients who have had the disease for 40 years. The young onset patients who do survive are at risk of hallucinations because of how long they have had the disease.

Question: Can hallucinations be related to Capgras syndrome?

Answer: Capgras syndrome is about not recognizing people. It is not hallucinations, they are issues usually seen with strokes. In Parkinson’s, the blood vessels are normal, the nerves are damaged, whereas in strokes it could be different. It is different. 

[Editor’s Note:  Dr. Goetz seems to be overlooking Capgras, a delusional disorder common in Lewy body dementia.]

Questions: Is there anything that can be done to help a family member come down from a hallucination?

Answer: If the person is not agitated, tell that person they are hallucinating and add stimuli such as lights or radio to redirect their attention. 

Question: What can care partners do when their loved one is having delusions about infidelity?

Answer: It is a horrible situation because even though we understand it cognitively, it hurts to be accused of that. Your heart breaks. This is where the doctor has to help the pain because you cannot endure this alone. You need to speak up to your doctor because they have to know to be able to help you. Doctor appointments are a good place to bring up because it is neutral. 

Question: What do you advise for care partners in their own self-care?

Answer: Care partners endure a lot, and they are partners in it but it isn’t their Parkinson’s disease. Their health matters and they still have to look after themselves. Being able to communicate and share with others and a support group is very helpful, it is more difficult with the COVID-19 pandemic, but it is important. 

Questions: What words of advice would you give to patients who are scared of the stigma of psychosis?

Answer: The brain is managed by both neurologists and psychiatrists. There is a split and fear element if there is a psychiatric manifestation of a neurologic disease. If it is psychiatric it is somehow more scary for people, even if it is based on a neurological disease. It is all the same problem, but doctors are trained to have different specialties, and I would remind them that it is not a weakness or an additional problem and it is all part of a neurologic disease. Having an in-house psychiatrist is helpful so they are not sent out to a different facility which could add a stigma.