Hallucinations and delusions are familiar terms but most people aren’t sure what they really mean. A hallucination is a false perception: seeing, feeling, hearing, smelling, or tasting something that isn’t really there. Delusions are irrational and illogical thoughts that are not real. Hallucinations and delusions are caused by changes in the brain and can be experienced by people with dementia, delirium, illness, and changes in medication.
Parkinson’s disease (PD) is a degenerative neurological condition that most people think of as a motor disorder and associate with tremors, stiffness, or slowness of movement. But PD can also affect your mood and ability to think clearly. According to the Parkinson’s Foundation, living with the motor symptoms can be hard, but behavior changes can be even more frustrating and challenging, with a greater impact on quality of life.2
Who develops hallucinations and delusions?
About 20% of people with Parkinson’s will develop some form of hallucinations or delusions. Risk factors include dementia, depression, sleep disorders, impaired vision, PD medications, and advance stages of the disease.3
Hallucinations and delusions are components of a condition called psychosis. People who’ve had Parkinson’s for more than 20 years will be more likely to experience elements of behavior and memory deficits that can lead to Parkinson’s disease psychosis.2
What are hallucinations?
Hallucinations can be tricks your mind plays on your senses and happen when you are awake. There are 5 categories:
Visual – seeing things that are not there
Auditory – hearing sounds or voices
Olfactory – smelling odors that are not real
Tactile – feeling imaginary things
Gustatory – tasting a bitter or unusual taste
Visual hallucinations are the most common experienced by people with PD. You might believe there is an animal or person in the room who is not there. Common examples include a cat that is not your pet scampering across the living room floor, or a neighbor sitting at your dining room table when no one is in fact there. In the beginning, hallucinations can be bothersome but manageable because most people know they are not real. This is called retaining insight.3 Good lighting, clutter-free surroundings, and communicating with your family and care team can make managing hallucinations easier. Over time some people may lose insight, and for them hallucinations can feel more real and threatening.
Sharing information with your doctors can help them manage medications and evaluate whether adjustments in surroundings, activities, and treatment can improve quality of life.
What are delusions?
Delusions are false, fixed beliefs. They occur less frequently in people with Parkinson’s. Brought on by medication, dementia and delirium, they generally occur at night, cause confusion and are more likely to result in behavioral disturbance displayed by aggressive or agitated states. There are different forms of delusions, like with hallucinations, but the most common in PD are persecutory and jealousy. The thought that your partner is cheating on you is very common. It can be disturbing for the whole family because delusions are not deliberate. There is no way to control them or, once experienced, to reason through or argue over them.2
How are hallucinations or delusions treated?
Your medical team should be aware of non-motor issues, just like your physical symptoms. Internists, neurologists and psychiatrists together can help determine the right course for each person. There are antipsychotic medications that are safe and can help to reduce the symptoms of Parkinson’s disease psychosis; but there are even more antipsychotics that are contraindicated for PD. It is always important to let a medical provider know you have Parkinson’s when seeking emergency care or treatment for something by doctors who are not a part of your regular medical team.
There is only one drug, pimavanserin, approved in 2016 by the FDA specifically for PD. It has a mechanism of action that doesn’t block dopamine. This has made it a safer drug for people with Parkinson’s. Two other medications, quetiapine and clozapine, that have been used for a longer time, are also considered safe for treating hallucinations and delusions in people with PD.2
Hallucinations and delusions are most often caused by high levels of dopamine in the brain. This is generally due to the medications used to manage motor symptoms of PD.4 It can be trial and error to find the right balance as long as it is managed by your doctors. You should never start or stop medications without physician guidance. Caregiver/family involvement can play an important role in helping to manage these psychological symptoms of Parkinson’s disease.
Hallucinations, delusions and paranoia. Alzheimer's Association website. Updated April 2017. https://www.alz.org/national/documents/topicsheet_hallucinations.pdf. Accessed online January 28, 2018.
Psychosis. Parkinson's Foundation website. Published 2016.
http://parkinson.org/sites/default/files/NPF-Psychosis. Accessed online January 28, 2018.
Hallucinations/Delusions. Parkinson's Foundation website. http://parkinson.org/Understanding-Parkinsons/Symptoms/Non-Movement-Symptoms/Hallucinations-Delusions. Accessed online January 28, 2018.
Hallucinations and delusions in Parkinson's. Parkinsons.org.uk website. Updated May, 2013. https://s3-eu-west-1.amazonaws.com/puk-live-1-d8-ie/2017-03/Hallucinations%20and%20Delusions.pdf. Accessed online January 28, 2018.