Alzheimer’s disease and Parkinson’s disease are both neurodegenerative diseases. There are similarities between the two conditions. There are also differences in symptoms, treatment, risk factors, and outlook for people with the conditions.

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Neurodegenerative diseases cause progressive damage to cells in the nervous system. The effects of these diseases can impact functions such as a person’s memory, behavior, and movement.

Alzheimer’s disease (AD) and Parkinson’s disease (PD) are two of the most common neurodegenerative diseases. While they share some similarities, they also have important differences.

AD is the most common type of dementia. Dementia is a progressive loss of cognitive function. This includes things such as thinking, memory, and problem-solving skills.

People with AD have abnormal accumulations of two proteins in their brains:

  • beta-amyloid outside of nerve cells (amyloid plaques)
  • tau protein inside of nerve cells (neurofibrillary tangles)

The underlying cause of these changes remains unknown. However, their presence is associated with the death of nerve cells, leading to the symptoms of AD.

PD is a condition where nerve cells in a part of the brain involved in movement become damaged and begin to die, leading to progressively increasing problems with movement.

PD may also lead to nonmotor symptoms and changes in memory, thinking, and behavior.

People with PD have accumulations of the protein alpha-synuclein in their nerve cells called Lewy bodies. It’s believed that Lewy bodies contribute in some way to the damage and death of nerve cells in PD.


There are several similarities between AD and PD. Both are neurogenerative diseases with a gradual onset that typically affect older adults. Additionally, both are characterized by unusual accumulations of protein in the brain.

The symptoms of both AD and PD become worse over time, and there’s no cure for either condition. Treatments focus on managing symptoms and improving quality of life. A combination of drug and nondrug therapies is used.


However, there are important differences between AD and PD. For example, the effects of AD largely impact thinking and memory, although movement symptoms can also happen.

The main symptoms of PD involve movement, although nonmotor symptoms can occur as well. People with PD are also at risk of developing PD dementia, a type of Lewy body dementia.

In addition to what we’ve discussed above, both AD and PD also have specific differences in things such as treatments, risk factors, and outlook for people with the conditions.

We’ll break down each of these topics in more detail below.

Alzheimer’s disease

The symptoms that someone with AD experiences can depend on how advanced their disease is. General symptoms of AD can include:

Parkinson’s disease

The symptoms of PD can vary greatly between individuals and also depend on how advanced PD has become. Overall, the main symptoms of PD are:

People with PD may also have a variety of symptoms that aren’t related to movement. These include:

Alzheimer’s disease

There’s no cure for AD. However, there are several drugs that can treat the symptoms of AD. These include drugs such as donepezil (Aricept) and rivastigmine (Exelon), which work by regulating the levels of chemical messengers in the brain.

Other drugs called aducanumab (Aduhelm) and lecanemab (Leqembi) may reduce amyloid plaques in the brain.

Aducanumab and lecanemab to treat Alzheimer’s disease

Both aducanumab and lecanemab were approved by the Food and Drug Administration (FDA) using the accelerated approval pathway.

This allows individuals with serious health conditions for which there are limited treatments to have access to potentially beneficial therapies. However, if further trials can’t show a benefit, the FDA can withdraw the drug’s approval.

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Sometimes other drugs are also used to treat AD. For example, antipsychotic drugs may be used to manage agitation or aggression in some individuals with AD, whereas certain types of antidepressants can help address depression.

Nondrug treatments can also help people with AD. These include:

  • keeping yourself mentally stimulated
  • engaging with a therapist or counselor to help cope with the effects of AD
  • getting mild to moderate levels of exercise
  • eating a healthy, balanced diet such as the MIND diet — this stands for “Mediterranean-dietary approaches to stop hypertension (DASH) intervention for neurodegenerative delay” — or the Mediterranean diet
  • developing a support network that can help improve your mental and emotional well-being

Parkinson’s disease

As with AD, there’s no cure for PD. Drugs such as levodopa-carbidopa (Sinemet) and others can help address the motor symptoms of PD.

Additional drugs can also be used to manage the nonmotor symptoms of PD. One example is prescribing antidepressants to treat depression associated with PD.

Other types of treatments can also be beneficial for people with PD, including:

Deep brain stimulation may also be helpful for some people with PD that doesn’t respond well to medications.

Alzheimer’s disease

The risk factors for AD include:

Parkinson’s disease

The risk factors for PD are:

Alzheimer’s disease

AD is progressive, meaning that it gets worse as time passes. Those in the later stages of AD have problems swallowing. This increases the risk of aspiration pneumonia, one of the most common causes of death in people with AD.

AD was the seventh leading cause of death in the United States in 2021. Most older adults with AD have a life expectancy of 4 to 8 years after their diagnosis.

Parkinson’s disease

PD is also progressive. Generally speaking, it’s difficult to determine how each individual with the condition will progress. While the life expectancy of people with PD is similar to the general population, their quality of life can be reduced in late stages.

The effects of PD typically lead to some level of disability within 10 years. Additionally, studies have estimated that 20 to 40% of people with PD are also living with PD dementia.

How common are Alzheimer’s disease and Parkinson’s disease?

The Alzheimer’s Association estimates that AD is the cause of 60 to 80% of dementia cases. They also estimate that 6.5 million people ages 65 years and older in the United States are living with AD.

PD is less common. The Parkinson’s Foundation estimates that nearly 1 million people in the United States are living with PD.

Can Alzheimer’s disease or Parkinson’s disease be prevented?

There’s no known way to prevent AD or PD for sure. However, implementing healthy lifestyle habits, such as eating a healthy diet and getting regular exercise, may help lower your risk.

AD and PD are two of the most common neurodegenerative diseases. Both are progressive conditions with no known cure. However, treatments can help manage symptoms and boost quality of life.

While AD and PD do have some similarities, they also have several important differences. These can include their predominant symptoms as well as differences in treatments, risk factors, and outlooks for people with the conditions.