How Long Does Dementia Last?

Updated July 19, 2017

Often thought to be a part of the normal process of ageing, dementia is a disorder characterised by a group of neurological symptoms, or abnormalities. There is a slow progression and deterioration of mental brain function, namely affecting memory, learning and reasoning abilities. Over 6 million people in the U.S. have dementia, as it is responsible for more than half of all those admitted to nursing care facilities. Those with dementia eventually become totally dependent upon others for their care.


The rate of progression of dementia depends upon the cause and will vary. Deterioration typically occurs over a period of 2 to 10 years.


While dementia encompasses many symptoms, there are two principle symptoms associated with it: impaired language or judgment and memory loss.

Someone with dementia may be disoriented to time and place, or forget who she is. She may not even remember who other people are, much less their names. Dementia causes people to act inappropriately. Symptoms vary as they are determined by their cause. Some of the more notable signs of dementia include agitation, confusion, hallucinations, lack of planning or organising ability, paranoia, changes in personality and difficulties with reasoning.

In its advanced stage, the brain is unable to function at all. People who suffer from advanced dementia cannot feed themselves, talk or even walk.


Dementia is caused by nerve cell damage in the brain. While it may have no other attributable cause, dementia does develop out of many other disorders affecting the brain. According to National Institutes of Health, Alzheimer's disease is the number one cause of dementia in people ages 65 and over. It results in progressive brain damage, and is always fatal.

As a person ages, there is an increased risk of developing dementia. Other risk factors include smoking or alcohol abuse, atherosclerosis, high cholesterol and LDL's, diabetes and Down syndrome. While those with a family history of dementia are at risk of getting the disease, many never do.

Types of Dementia

All types of dementia fall underneath either one of two categories: cortical or subcortical. Cortical dementia is manifest by brain damage affecting the cerebral cortex. It is characterised by memory loss, language difficulties and inappropriate behaviours. Alzheimer's disease, vascular dementia, lewy body dementia and dementia induced by alcohol abuse are principle types of cortical dementia.

Subcortical dementias are manifest by damage below the cortex causing motor coordination problems, mood or personality changes and memory loss. They are typically due to a medical condition, such as Parkinson's disease. Other disease conditions causing subcortical dementia are Huntington's disease, HIV-AIDS, syphilis, B12 deficiency and hypothyroidism.


Dementia in general is irreversible and incurable. Those forms of dementia which are due to treatable conditions, such as alcohol abuse or deficiency related dementias, are potentially reversible by treating the underlying problem. Even though certain physical conditions may not be the immediate cause of the dementia, it is essential to treat these as it helps sustain overall health of the individual suffering from dementia.

Certain medications have been proven to be helpful, at least temporarily and may even help slow the progression of disease. Acetylcholinesterase inhibitors, such as donepezil and rivastigmine act to increase availability of acetylcholine, a neurotransmitter responsible for nerve cell communication in the brain. Effectiveness varies with each individual and with some, it is not useful. Use of these drugs are helpful in that they improve the symptoms of dementia; they do not prevent progression of the disease or reverse nerve cell damage, however.

Although best controlled through cognitive and behavioural therapies, certain antipsychotic and anticonvulsant medications are beneficial in the control of disruptive behaviours.


It is a commonly held belief that losing memory naturally comes as people age. While ageing does cause changes within brain tissue causing slower learning ability and short term memory loss, those with a dementia disorder are unable to function. It is also thought that Alzheimer's disease only affects the elderly. There are sufferers who are much younger. In fact, according to the Alzheimer's Association, there are over 200,000 people with the disease who are much younger. It can affect people as young as 30 years of age.

Cite this Article A tool to create a citation to reference this article Cite this Article

About the Author

Aunice Reed is a medical science writer living in Los Angeles, Calif. With over 10 years previous nursing experience, Reed has been writing for over six years and has attended University of Northern Iowa, University of California, Los Angeles and Los Angeles Harbor College.