Dementia

Medically reviewed by Drugs.com. Last updated on Mar 20, 2023.

What is Dementia?

Dementia is a pattern of mental decline caused by different diseases or conditions. Most commonly, dementia occurs when brain nerve cells (neurons) die, and connections between neurons are interrupted. These disruptions have a variety of causes and usually cannot be reversed.

Alzheimer's disease causes over 60% of all dementias. Vascular disease, such as stroke, is the second most common cause.

Lewy body disease, which causes neurons in the brain to degenerate, causes another 20% of dementias.

Other conditions that can cause dementia include:

Lewy body disease
Creutzfeldt-Jakob disease
traumatic head injury
acquired immunodeficiency syndrome
alcohol abuse
degenerative diseases, such as Huntington's disease and Pick's disease
many other rare degenerative conditions.

In rare cases, dementia is caused by a treatable condition, and it may be partially or entirely reversed if the condition is diagnosed and treated early:

depression
adverse reactions to drugs
infections, such as syphilis or fungal meningitis
metabolic conditions, such as deficiencies of vitamin B₁₂ or thyroid hormone.

In the developed nations, about 15% of people older than 65 are thought to have dementia.

Symptoms

Symptoms of dementia emerge slowly, get worse over time and limit the person's ability to function.

The first symptom of dementia is memory loss. Everyone has memory lapses from time to time. However, the memory loss of dementia is greater and affects your ability to function. For example, forgetting where you put your car key is normal. Forgetting how to use the key is a possible symptom of dementia.

Often, someone with dementia does not realize that he or she has a problem. Instead, family members recognize that something is wrong.

Along with memory loss, a person with dementia may have trouble with complex mental tasks. They may have difficulty balancing a checkbook, driving, knowing what day it is and learning new things. They may be inattentive, and display poor judgment. Their mood and behavior also may change.

As the disorder progresses, the person may have difficulty speaking in full sentences. They may not recognize their surroundings, or other people. They may have problems with personal care, such as bathing. In some cases, a person with dementia may see or hear things that are not (hallucinations and delusions). They may get very agitated, and may withdraw from other people.

Diagnosis

The doctor will ask when memory problems started and how quickly they got worse. This information, together with the person's age, can help suggest a likely diagnosis. For example:

If the person is elderly and has had consistently worsening memory and other problems for several years, a doctor may suspect Alzheimer's disease.
If symptoms got worse rapidly, then Creutzfeldt-Jakob disease may be a likely cause.
If the person has had a prior stroke or is at higher risk of stroke, the doctor will consider vascular dementia as the underlying cause.

However, the exact cause of dementia in any individual can often be difficult to determine.

To diagnose dementia, a doctor looks to see if a person's memory gets progressively worse, along with at least one of the following:

difficulty understanding or using language
the inability to perform a purposeful act or sequence of motor activities
the inability to recognize familiar objects or people
difficulty doing such complex tasks as planning or organizing.

Doctors test people by testing memory and attention. A commonly used tool to screen for dementia is the Mini Mental State Exam. It consists of 11 short assessments, such as asking the person what day and year it is or have the person count backward from 100 by sevens (100, 93, 86, etc.). If the person answers correctly, dementia is less likely.

Laboratory tests can narrow down the possible causes. Some tests include:

Magnetic resonance imaging (MRI) or computed tomography (CT) scans – These create pictures of structures inside the head (similar to the way X-rays create images of bones). The pictures can reveal brain tumors and stroke. If these tests do not show any major abnormalities, the diagnosis could be Alzheimer's disease.
Positron emission tomography (PET) scans – Increasingly, these scans are being used to detect Alzheimer's disease, and conditions that can turn into Alzheimer's disease. They are not yet widely available.
Blood tests – These are done to help judge overall health and also to determine if vitamin B₁₂ deficiency or very low levels of thyroid hormone may be contributing to the decreased mental functioning.
Lumbar puncture (spinal tap) – This test is rarely needed to evaluate dementia. Occasionally, your doctor may want to be certain that fluid pressure around the brain is normal. Also laboratory testing on a sample of spinal fluid can make sure there is no infection. Researchers are studying proteins in the spinal fluid to see if certain patterns can detect specific causes of dementia, or can predict the outlook (prognosis).

Expected duration

In most cases, dementia gets worse and cannot be cured. A person with dementia may live for months, years or decades, depending on the cause of the dementia and whether the person has other medical conditions.

In the rare cases in which dementia is caused by a treatable condition, such as infection, metabolic disorder or depression, the dementia usually is reversed after treatment.

Prevention

Most of the causes of dementia cannot be prevented. Good personal health habits and medical care, however, can prevent some types of dementia. Here are some things you can do:

Dementia caused by Alzheimer's disease and stroke – Many of the same practices that reduce the risk of heart disease and stroke also reduce the risk of Alzheimer's disease. Monitor and control your blood pressure and cholesterol, exercise every day, and eat a balanced diet with plenty of fruits and vegetables to maintain a healthy body weight, try to maintain a healthy weight, avoid tobacco.
Alcohol-related dementia – Limit the amount of alcohol you drink.
Traumatic dementia – Avoid head injury by always using seat belts, helmets and other protective equipment.
Some infection-related dementias – Avoid high-risk sexual behavior.
Vitamin-deficiency dementia – Make sure your diet has enough B vitamins, especially vitamin B₁₂. Your doctor may want to order a blood test for B₁₂ level.
Hormone-related dementia – Your doctor may want to order a blood test called TSH (thyroid stimulating hormone) to make sure your thyroid is functioning properly.

Keeping your mind active and your body fit may help to prevent mental decline and reduce or postpone memory loss. If you get daily physical exercise and continue to challenge your brain throughout life, you can help to protect your brain against mental decline.

Treatment

Sometimes the cause of dementia can be reversed, such as vitamin B₁₂ deficiency or an underactive thyroid. Treating these conditions may improve the dementia. Other reversible factors that can contribute to symptoms include overuse of alcohol and depression.

People with vascular dementia may show less mental decline if their blood pressure is controlled, they stop smoking, lower LDL (andquot;bad" cholesterol), exercise regularly and maintain a healthy weight.

In some people, medications for Alzheimer's may help with behavioral symptoms and perhaps slow down the mental decline. They may delay the need for placement into a nursing home. Acetylcholinesterase inhibitors, such as donepezil (Aricept), galantamine (Razadyne) and rivastigmine (Exelon), can be prescribed for mild to moderate Alzheimer's dementia. Memantine (Namenda) is approved for moderately severe Alzheimer's dementia.

These same medications are sometimes used to treat the dementia associated with Lewy body disease.

Two new treatments for Alzheimer's disease using monoclonal antibodies directed against brain amyloid beta have been granted accelerated approval by the U.S. Food and Drug Administration (FDA). They are aducanumab (Aduhelm) and lecanemab-irmb (Leqembi), which may slow and even potentially halt progression of the disease.

Depending on the cause of the dementia, several specialists may be involved in care, including neurologists, psychologists, psychiatrists or geriatric doctors. Nurses and social workers play a very important role in care.

Here are some easy to implement aspects of care that help ease symptoms:

familiar surroundings, people, and routines, because too much change can cause confusion and agitation
bright, active environments to help focus the person's attention and keep him or her oriented to the environment
safe environments so that the person cannot be hurt or get lost if he or she wanders away
physical exercise to improve balance and general good health
appropriate therapies, including music, art and occupational therapy, to provide stimulation and improve control of muscles.

Treatment options

The following list of medications are related to or used in the treatment of this condition.

Prognosis

The outlook for dementia depends on the cause and can vary by individual. For example, early treatment of dementia caused by a vitamin deficiency can lead to full recovery of memory. If stroke is the cause, the person's memory loss can remain stable for years.

Drugs may slow the rate of decline for some people with Alzheimer's disease.

In most cases, however, the disorder gradually gets worse. Depending on the cause, the person's age, general health and the availability of treatments, life expectancy can be as short as a few months or as long as 15 to 20 years.