What is the difference between alzheimer's and dementia?

Updated June 13, 2017

Many people are unsure what the differences are between Alzheimer's and dementia. Dementia is an umbrella term that describes a set of symptoms that can be present in a variety of conditions and illnesses. Alzheimer's is a progressive brain disease, and it is the most common cause of dementia.


The terms Alzheimer's disease and dementia are often used interchangeably, yet they are not the same thing. A person who suffers from dementia may or may not have Alzheimer's, but everyone who has Alzheimer's will suffer from dementia. Sometimes doctors and health professionals add to the confusion by using the term dementia instead of Alzheimer's. Some prefer to use the word dementia because the term Alzheimer's can be frightening and overwhelming.

Dementia Explained

Dementia is not an illness but a cluster of symptoms that may be present in certain conditions or diseases. It is an extensive decline in cognitive function that is so severe it interferes with one's daily activities. Symptoms of dementia include memory loss, personality and mood changes, confusion and a decline in problem-solving skills. There are numerous conditions that cause dementia. Sometimes, side effects from medications and other medical problems can cause dementia-like symptoms.

Alzheimer's Disease Explained

Alzheimer's disease is a condition that causes the gradual destruction of brain cells. Over time, the illness causes dementia by progressively robbing the patient of his memory, learning ability, communication skills and capacity for self care. In most Alzheimer's patients, the symptoms first appear after the age of 60, but Alzheimer's is not a normal part of ageing. Alzheimer's starts in the part of the brain that stores recent memory, then slowly spreads to other areas of the brain. The disease progresses through the brain at different rates, usually lasting from three to 20 years. Scientists are not certain what causes Alzheimer's.

Outcomes of Dementia

Many of the causes of dementia are reversible, including depression, vitamin B12 deficiency, medication interactions, malnutrition, infections and hormone or thyroid imbalances. Some medications for common conditions such as high blood pressure, depression, insomnia, arthritis and diabetes can also produce side effects that mimic dementia. There are also a number of conditions that lead to irreversible dementia. According to the Alzheimer's Association, there are over 170 illnesses that cause irreversible dementia, with Alzheimer's at the top of the list.

Outcomes of Alzheimer's Disease

The progressive brain damage and dementia caused by Alzheimer's disease is irreversible. There are treatments available to slow the rate of decline caused by Alzheimer's, but, at this time, there is no cure. By the time the disease reaches its final stage, the brain has suffered widespread damage and shrinkage, ultimately resulting in death.

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About the Author

Sharon O'Neil has been writing professionally since 2008. Her work has been published on various websites, including Walden University's Think+Up. She has worked in international business and is a licensed customs broker. She is currently a supervisor with a social service agency that works with families to prevent child abuse and neglect. She obtained a Bachelor of Science in business from Indiana University.