What Causes Parkinson’s Disease and Alzheimer’s—Are They Related?

Neurodegenerative diseases affect millions of people around the world, with Parkinson’s disease (PD) and Alzheimer’s disease (AD) being two of the most common. Both are progressive, chronic disorders of the brain, but they differ in their symptoms, causes, and progression. This often raises the question: What causes Parkinson’s disease and Alzheimer’s—and are they related?

Understanding the Causes of Parkinson’s and Alzheimer’s

What Causes Parkinson’s Disease?
Parkinson’s disease is primarily caused by the gradual breakdown or death of neurons in a region of the brain called the substantia nigra. These neurons are responsible for producing dopamine, a neurotransmitter essential for coordinating movement. As dopamine levels decrease, symptoms like tremors, stiffness, and slowed movement begin to appear.

While the exact cause is not fully understood, several factors are believed to contribute:

• Genetic mutations: Certain inherited genetic mutations are linked to Parkinson’s, although they are rare.
• Environmental exposures: Prolonged exposure to certain toxins or pesticides may increase risk.
• Age and gender: The disease most often affects people over age 60 and is more common in men than in women.

What Causes Alzheimer’s Disease?
Alzheimer’s disease, the most common form of dementia, primarily affects memory, thinking, and behavior. It’s associated with the buildup of amyloid plaques and tau tangles in the brain, which disrupt communication between neurons and eventually lead to cell death.

• Key contributing factors include:
• Age: The single greatest risk factor.
• Genetics: The APOE-e4 gene variant increases risk.
• Lifestyle and heart health: Conditions like diabetes, high blood pressure, and smoking may increase susceptibility.
• Brain injury: History of head trauma may also be a factor.

Are Parkinson’s and Alzheimer’s Related?
Although Parkinson’s and Alzheimer’s are distinct diseases with different causes and symptoms, they do share some common features:

• Both are neurodegenerative: They involve progressive damage to neurons in the brain.
• Risk increases with age: Both diseases are more common in older adults.
• Overlap in symptoms: Some cognitive decline can occur in later stages of Parkinson’s, and some people with Alzheimer’s may experience movement issues.

​There is also a condition called Parkinson’s disease dementia (PDD) that occurs in some individuals with Parkinson’s, and Lewy body dementia (LBD) which shares characteristics of both PD and AD. These overlapping conditions highlight how the boundaries between these diseases can blur.

Whole-Person Support Through PASWFL

Navigating life with Parkinson’s can be challenging, but you don’t have to do it alone. For over 25 years, the Parkinson’s Association of Southwest Florida (PASWFL) has been improving lives through education, wellness programs, and support networks.

Each week, PASWFL offers over 25 free programs including:

• Fitness and movement classes
• Cognitive wellness and speech therapy
• Care partner and peer support groups
• Education sessions with Parkinson’s experts

Membership is completely free, and it’s open to individuals with Parkinson’s and their care partners throughout Southwest Florida.

Join the PASWFL CommunityEmpower yourself with the tools, community, and knowledge to live well with Parkinson’s.
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For more information, visit www.parkinsonassociationswfl.org and take your first step toward wellness today.