Does Parkinson’s Disease Increase Your Risk of Dementia?

Parkinson’s disease (PD) can cause symptoms that are physical, emotional, and mental. If you or someone you know is living with Parkinson’s, you may have heard that some people with Parkinson’s have dementia.  

And you may be wondering how concerned you should be. Does Parkinson’s cause dementia, and does it happen to everyone living with PD? Here we’ll review what you need to know about the link between Parkinson’s and dementia. And we’ll cover ways to lower the risk of developing dementia. 

Does Parkinson’s disease cause dementia?

Parkinson’s disease can lead to dementia. Dementia is when someone has problems with thinking, memory, and reasoning skills that are severe enough to interfere with daily tasks. PD can cause dementia because it involves damage to parts of the brain, especially in an area of the brain called the substantia nigra. This can affect several body systems, which include:

• Movement problems: The most notable symptoms of Parkinson’s are a characteristic “pill-rolling” tremor (in which a person rubs their thumb and index finger together), and a shuffling walk.People with PD can also experience muscle stiffness, slow movements, and an increased risk of falling. 

• Cognitive: The damage that PD causes to the brain can lead to problems with memory and thinking. In some people, this will lead to eventual dementia. 

• Psychiatric: PD increases the risk of mood disorders like depression and anxiety. People with PD are also more likely to experience paranoid thoughts, hallucinations, and impulse control problems. 

• Digestive: Parkinson’s is also often linked with a general slowing of digestion. Constipation and swallowing issues can be a big problem.  

• Skin: PD is even associated with some common skin complaints. Such complaints include dry skin and seborrheic dermatitis. Seborrheic dermatitis causes greasy, yellowish scaling of the face, ears, and scalp. It’s often associated with PD.  

Does Parkinson’s disease always lead to dementia?

Not every person with Parkinson’s disease will go on to develop dementia. But the longer you live with Parksinson’s, the higher the risk. For those who have lived with PD for 10 years or more, the risk of dementia is around 75%. It’s not possible to say exactly who will go on to develop dementia. But there are some known factors that seem to increase the risk in those living with PD, such as: 

• Older age

• More severe motor symptoms

• Visual hallucinations

• Preexisting cognitive impairment

• REM sleep disorder

• High blood pressure

• Drop in blood pressure when you stand up

• Abnormal color vision

Is Parkinson’s dementia different from other types of dementia?

Parkinson’s disease has similarities with other forms of dementia, and also some unique features. Knowing the different types of dementia and their common features can help you distinguish them.  

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• Dementia affects communication. If you’re taking care of someone with dementia, make sure to review some helpful dos and don’ts to help you communicate well with your loved one. 

• Parkinson’s treatment: There’s no cure for Parkinson’s disease, but medications can help treat the symptoms. Learn about medications and other treatment options to improve quality of life. 

• Parkinson’s and the power of exercise: Exercise can help people with Parkinson’s feel better mentally and physically. Read about one man’s journey from Parkinson’s diagnosis to American Ninja Warrior champion.

Parkinson’s and dementia with Lewy bodies

Parkinson’s dementia is considered a type of Lewy body dementia (LBD). The other type of dementia that falls into this category is dementia with Lewy bodies (DLB). Both of these conditions involve a buildup of abnormal proteins called Lewy bodies in brain cells. They share similar symptoms like tremor, shuffling gait, and memory loss. But visual hallucinations are more common with DLB.  

The main difference between Parkinson’s dementia and dementia with Lewy bodies is what’s known as the “1-year rule.” Dementia with Lewy bodies is diagnosed when the cognitive and physical symptoms start together, or within the first year. In Parkinson’s dementia, the physical symptoms show up first. Symptoms of dementia will start at least 1 year later, and often many years following the initial physical symptoms. Together, Lewy body dementias make up the third most common type of dementia. 

Alzheimer’s dementia

Alzheimer’s dementia is the most common form of dementia. It accounts for 70% of all dementias. The primary feature is a gradual loss of memory and thinking skills. Everyone with Alzheimer’s disease (AD) develops dementia. 

People with Alzheimer’s can experience delusions and hallucinations as the disease progresses, but this is less common. There aren’t typical motor or movement problems linked to AD. But in later stages, people with Alzheimer’s often have difficulty moving and getting around.

Vascular dementia

Vascular dementia is the second most common type of dementia. In vascular dementia, dementia develops because blood vessels aren’t able to supply enough oxygen to the brain. This is most often seen in people who have had a stroke. 

The symptoms of vascular dementia depend on the part of the brain affected by the stroke.  Vascular dementia remains relatively stable unless another stroke occurs. This is unlike other dementias, which tend to worsen progressively.

Frontotemporal dementia

Frontotemporal dementia (FTD) is less common than the other dementia types already discussed. It generally presents in a much different way from other types of dementia. It often occurs at younger ages than other types of dementia. It’s characterized by unusual behaviors — such as inappropriate social behavior — and personality changes more so than memory loss.    

Other dementia types

All the other types of dementia are less common. Anything that affects brain functioning can cause dementia. So dementia can be seen in people with a history of traumatic brain injury and alcoholism. Infectious diseases can also lead to certain types of dementia. Examples include neurosyphilis, HIV-related dementia, and prion disease. 

How can you tell if Parkinson’s dementia is starting?

It’s common to be more forgetful as you age, or to think through problems more slowly. This includes people with Parkinson’s disease. But in people with dementia, the symptoms go beyond occasional forgetfulness. These changes are severe enough to interfere with daily life and safety. The following symptoms would suggest the possibility of dementia and a need for further testing:

• Frequent forgetfulness or becoming easily confused

• Missing appointments 

• Trouble paying bills or managing money

• Getting lost in familiar areas

• Showing poor judgment or trouble making decisions

• Trouble using the correct words

• Frequently repeating the same statements or questions

• Difficulty using familiar objects or appliances

• Hallucinations

Can you prevent Parkinson’s dementia?

There’s currently no treatment that can prevent people with Parkinson’s from developing dementia. But there are habits that can slow the progression of Parkinson’s disease in general. Additionally, there are some lifestyle changes that may reduce overall risk for dementia.

Exercise 

Exercise has a proven protective effect in slowing disease progression for people living with PD. It can improve brain health and may lower the risk of dementia in people with PD. The American Heart Association (AHA) recommends 150 minutes of moderate exercise weekly. People with Parkinson’s should do as much as they can. 

Walking and balance exercises, including tai chi and yoga, may also be helpful. Working with a trainer can be great for those who need assistance while exercising. Prescribed exercise such as physical and occupational therapy can also help to restore mobility and reduce fall risk.

Try the Mediterranean diet

The Mediterranean diet has shown benefits for lowering overall risk for dementia. In addition to its brain-protecting effects, the Mediterranean diet has multiple other health benefits. It can help lower the risk of heart disease and help people live longer.  

Avoid alcohol and tobacco

Drinking too much alcohol and smoking tobacco are both shown to increase the risk for dementia. Drink alcohol in moderation or not at all, and avoid smoking. If you do smoke, look for ways to lower your cigarette use or quit entirely. 

Treat mental health conditions

Parksinon’s disease carries a four-fold increased risk for depression. Depression in itself can cause memory changes, and increase risk for dementia. When it comes to attention-deficit hyperactivity disorder (ADHD), one large study found that people with ADHD were almost three times more likely to develop dementia. But those who were treated with stimulant medications didn’t have an increased risk. If you or your loved one is experiencing any mental health symptoms, make sure to talk about this with the healthcare team. 

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Written by:

Jennifer Arnouville, DO, FAAFP

Jennifer Arnouville, DO, FAAFP has been a practicing physician since 2010. For the first 12 years of her career, Dr. Arnouville had a primary care geriatrics practice.

Edited by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

Reviewed by:

Karen Hovav, MD, FAAP

Karen Hovav, MD, FAAP, has more than 15 years of experience as an attending pediatrician in a variety of clinical settings. She has worked in a large academic center in an urban city, a small community hospital, a private practice, and an urgent care clinic.

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