Key takeaways

  • Alzheimer’s disease is the most prevalent cause of dementia, accounting for a significant majority of cases due to the buildup of amyloid and tau proteins in the brain.
  • Vascular dementia results from reduced blood flow to the brain, often caused by strokes or conditions like obesity and diabetes, leading to oxygen deprivation and brain cell death.
  • Lifestyle modifications such as a balanced diet, regular exercise, and limiting alcohol and smoking can potentially prevent some cases of dementia by addressing modifiable risk factors.

Major neurocognitive disorder, also known as dementia, is a neurodegenerative condition characterized by a decline in cognitive function that could affect your daily activities.

There are 13 different forms and causes of dementia in the American Psychiatric Association’s (APA) Diagnostic and Statistical Manual of Mental Disorders, 5th edition, text revision (DSM-5-TR).

Keep reading to learn more about what causes dementia.

Alzheimer’s disease is the most common cause of dementia. According to the Alzheimer’s Association, Alzheimer’s causes 60% to 80% of dementia.

The exact cause of Alzheimer’s is not known, but researchers suggest it may be caused by the buildup of two proteins called amyloid and tau in the brain.

A buildup of amyloid causes plaques in the brain that can disrupt communication between nerve cells and cause inflammation. A buildup of tau may cause neurofibrillary tangles, which may contribute to the disintegration of important brain cells.

Genetic mutations may also play a role in early onset Alzheimer’s, which could affect people in their 30s and 40s.

Lewy body dementia is a type of progressive dementia that affects around 5 in 100 people with dementia.

It’s caused by abnormal structures in the brain called Lewy bodies, which are small masses of a protein called alpha-synuclein. They’re usually found in the brain’s outer layer (cortex), stem, and limbic region. This may lead to symptoms like difficulty thinking, understanding language, and moving.

Lewy bodies are also commonly found in the brains of people with Parkinson’s disease.

Vascular dementia affects approximately 15 in 100 people with dementia.

It’s caused by a reduction in blood flow to the brain, which prevents enough oxygen from getting to your brain cells. If the oxygen flow is interrupted long enough, brain cells can die.

Reduced blood flow may be caused by stroke or experiencing several “ministrokes” (transient ischemic attacks). Research suggests that around 1 in 5 people who experience a stroke will develop dementia within 1 year.

Underlying health conditions like obesity, diabetes, and high blood pressure may also increase the risk of blood vessels in the brain narrowing or becoming blocked, which could lead to vascular dementia.

Frontotemporal dementia is a group of diseases that cause significant changes in behavior or language capability.

It affects 1 in 4 people with dementia who are 65 years and older. It’s also the second most common cause of dementia in people younger than 65 years old.

These diseases usually involve neurofibrillary tangles that cause brain cell degeneration and shrinkage in the frontal and temporal lobes of the brain. These areas control personality, judgment, emotion, and language.

Healthcare professionals suggest that frontotemporal dementia can run in families, suggesting that genetics may be an important causal factor.

Traumatic brain injuries (TBIs) can result from any kind of major impact to your skull, such as from falling down and hitting your head.

According to the Alzheimer’s Association, TBIs may have long-term effects that may affect your brain and increase your risk of dementia. For instance, you may be up to five times more likely to develop dementia if you have a TBI.

Individuals who have experienced multiple traumatic brain injuries are at even greater risk of developing dementia. They’re at risk for a condition known as chronic traumatic encephalopathy, which is a type of dementia.

Healthcare professionals usually classify TBIs as mild, moderate, or severe based on the level of unconsciousness experienced. Moderate and severe TBIs are more likely to cause dementia than mild TBIs, which may cause short-term symptoms like disorientation, headaches, and dizziness.

Researchers have identified several other causes and conditions that may contribute to dementia, including:

These conditions are often caused by various risk factors, including family history and lifestyle choices.

According to the World Health Organization (WHO), the following risk factors may increase your risk of dementia:

  • being age 65 years and older
  • having a family history of dementia
  • having some medical conditions, such as high blood pressure (hypertension), diabetes, obesity, and depression
  • living a sedentary lifestyle
  • smoking
  • regularly drinking alcohol

Some dementia risk factors, such as age and family history, aren’t modifiable.

However, the United Kingdom’s National Health Service (NHS) suggests that making certain lifestyle and dietary changes could help reduce some risk factors and prevent 4 in 10 cases of dementia.

Some of these prevention measures include:

Learn more about how to prevent dementia.

What is one of the main causes of dementia?

Alzheimer’s disease is the leading cause of dementia, accounting for up to 80% of cases.

Can stress cause dementia?

Some research suggests that long-term stress may increase your risk of developing dementia. However, more research is needed to fully understand the link between stress and dementia.

What are the triggers of dementia?

Several risk factors may greatly increase your risk of dementia, including stroke, head injuries, genetics, and infections like HIV, Lyme disease, and syphilis.

Dementia refers to a general decline in cognitive abilities that may have an impact on your day-to-day activities.

Researchers have identified several different causes of dementia, including Alzheimer’s disease, stroke, and traumatic brain injuries, among others.

Speak with a healthcare professional if you begin to notice symptoms of dementia, such as memory loss and difficulty thinking. Early diagnosis and treatment may help slow disease progression, prevent complications, and improve quality of life.