What Is Dementia?

Dementia is not one disease, but a term that refers to different disorders that affect the brain and impair a person’s memory, thinking, behavior, or emotions enough to interfere with daily life and independence.

Alzheimer’s disease is the most common type, accounting for 60% to 80% of all dementia cases. Other types of dementia include vascular, Lewy body, frontotemporal, and mixed dementia, which refers to dementia from more than one cause. Although dementia is more common with age, it is not considered a normal part of aging.

This article will examine the signs, causes, diagnosis, treatment, and prevention of dementia.

Signs of Dementia

Because dementia refers to multiple conditions, symptoms can vary greatly between individuals. Symptoms can occur as nerve cells in the brain stop working properly and eventually die. Symptoms may also be due to a buildup of plaque in the brain.

Dementia occurs in stages, with symptoms typically progressing from mild, where the person can still function independently, to severe, where round-the-clock care is often needed.

Cognitive symptoms

Some common cognitive symptoms of dementia include problems with:

• Short-term memory. The person might forget or be confused about names, words, dates, or memories, or ask the same questions repeatedly. They may get lost or disoriented in familiar areas. Memory loss is one of the most common symptoms of Alzheimer’s disease, especially when it’s in the early stages.
• Communication. This can include using unusual words when referring to familiar objects, or having trouble speaking, reading, or writing.
• Reasoning, judgment, and problem-solving. The person might not be able to complete tasks he or she used to do without help. This can include things like managing bills and money, or making lists and following recipes.
• Attention. Those with dementia might lose interest in activities or events they used to enjoy.
  

Psychological symptoms

Some of the psychological symptoms of dementia include:

• Mood and personality changes. People with dementia can become confused, anxious, and suspicious. They may accuse others of stealing from them, be easily upset with others, or act impulsively. A person with dementia may also act aggressively.
• Withdrawing socially. A loss of the ability to communicate or pay attention can lead to a person withdrawing from activities and hobbies they used to take part in.
• Hallucinating, or experiencing delusions or paranoia 
  

In addition to cognitive and psychological symptoms, those with dementia can also experience physical symptoms such as loss of balance and coordination, or changes in visual perception.

Causes

Dementia is caused by changes in the brain, but in many cases the exact mechanisms that lead to dementia are unknown. For example, Alzheimer’s is believed to be caused by multiple factors including age-related brain changes, genetics, and environmental and lifestyle factors.

Amyloid plaques are known to play a role in Alzheimer’s disease. Amyloid plaques are made up of collections of beta-amyloid protein that form in the spaces between the brain’s nerve cells. This build-up of protein causes damage and makes it harder for cells to communicate with each other. However, scientists are still unsure exactly how amyloid plaque damages nerve cells.

Another characteristic of Alzheimer’s disease is the presence of neurofibrillary tangles called “tau” tangles in the brain. These tangles, caused by a buildup of tau protein, cause changes in the brain that appear to particularly affect memory.

Frontotemporal dementia and Lewy body dementia are also associated with abnormal amounts of certain proteins in the brain, while vascular dementia is caused by conditions that affect blood flow in or to the brain.

Risk factors

A number of risk factors are associated with an increased chance of developing dementia.

Unmodifiable risk factors, or risk factors you can’t control, include:

• Age. This is the biggest known risk factor for dementia, with the majority of cases occurring in those ages 65 and older.  
• Genetics. Having a family history of dementia increases your risk of getting it. There are more than 20 genes known to increase the risk of developing dementia.
• Race/ethnicity. Older Black Americans are two times more likely to have dementia than white Americans, and Hispanics are 1.5 times more likely to have dementia than white Americans.
• Sex. Women are more likely than men to experience dementia. In 2020, 35 million women worldwide had Alzheimer’s disease, compared to 20 million men. Women are more than twice as likely as men to die from dementia.

Modifiable risk factors, or those you can control, also play a role in the chances of developing dementia. They include:

• Unhealthy lifestyle behaviors. Being obese, physically inactive, smoking, and drinking too much alcohol all increase dementia risk.
• Heart disease/hypertension. Research is finding that brain health has an important connection to heart health. Having cardiovascular disease or high blood pressure increases the risk of developing dementia.
• Diabetes. Having diabetes is a known risk factor for developing Alzheimer's disease and vascular dementia.
  
• Social isolation. Having social connections has been shown to enhance brain function and reduce dementia risk.

Diagnosis

There is no one test to diagnose dementia. Healthcare providers typically will do a physical exam, take a medical assessment including family history, and run lab tests to first determine if another condition is causing symptoms.

Tests that can be used to diagnose dementia include:

• Cognitive and neurological tests. These tests evaluate both mental and physical function including memory, language, and sensory responses.
• Brain scans. Imaging including CT scans and magnetic resonance imaging (MRI) might be ordered to look for evidence of stroke or other changes in the brain that could be causing symptoms.
• Blood testing. A blood test measuring levels of beta-amyloid proteins associated with Alzheimer’s may be ordered.
  

Treatment

How dementia is treated depends on the type of dementia and if there is a known cause. In most cases, dementia cannot be cured. Medications can improve symptoms, mental function, and behavior, but do not slow dementia progression.

In 2021, the FDA fast-tracked approval for an intravenous drug called Aduhelm (aducanumab) for the treatment of mild cognitive impairment due to Alzheimer’s disease. Aduhelm is the first drug designed to remove amyloid proteins from the brain. However, the use of this drug has been controversial for several reasons including the potential for serious side effects including brain swelling and bleeding, and because the drug was not shown to significantly improve cognition in clinical trials.

Prevention

Because the causes of dementia aren’t fully understood, there is no guaranteed way to prevent it. However, managing modifiable risk factors can lower your risk of getting dementia.

Behaviors that can reduce the risk of developing dementia include:

• Exercising regularly
• Eating a healthful diet
• Maintaining a healthy weight
• Not smoking
• Managing health conditions linked with dementia such as diabetes and high blood pressure
• Participating in social activities
• Engaging in mentally-stimulating activities
  

Summary

Dementia is an umbrella term referring to a number of conditions that affect the brain and impair cognitive, psychological, and physical function. In most cases, the causes of dementia are not known, and a number of factors are believed to play a role.

The chance of being diagnosed with dementia increases greatly with age. Treatments can be used to help manage symptoms but do not slow dementia's progression. Making healthy lifestyle modifications can help lower the risk of getting dementia.

A Word From Verywell

Dementia can be a difficult diagnosis for both patients and their loved ones. If someone is displaying signs of dementia, it’s important to see a healthcare provider as soon as possible to make a diagnosis and rule out any other conditions that could be causing symptoms.

Medications and lifestyle changes can potentially improve symptoms but are most effective if initiated in dementia’s early stages. Because dementia is progressive, it’s also important to explore available resources early on. There are many organizations that offer support to both patients with dementia and their caregivers throughout all stages of the condition.