Difference Between Dementia and Alzheimer's Disease

Comparison and Difference between Dementia and Alzheimer’s Disease

Too often, patients and their family members are told by their doctors that the patient has been diagnosed with “a little bit of dementia.” They leave with a feeling of relief that “at least they don’t have Alzheimer’s.” There is great confusion about the difference between “dementia” and “Alzheimer’s disease.” The confusion is felt on the part of patients, family members, the media, and even healthcare providers. The purpose of this article is to reduce this confusion by defining and describing these two common and poorly understood terms.

“Dementia” is the term that is now used by many instead of the more out-of-date word, “senility.” It refers to a group of symptoms, including memory difficulties and problems in at least one other area of cognitive functioning (e.g., language, attention, problem solving, spatial skills, judgment, planning, organization), with these problems being severe enough to get in the way of normal daily living (e.g., social and occupational functioning). A good analogy to the term, dementia, is “fever.” Fever refers to an elevated temperature, indicating that the person is sick. But, it doesn’t give any information about what is causing the sickness. In the same way, dementia means that there is something wrong with the person’s brain, but doesn’t provide any information about what is causing the memory and other cognitive difficulties. Dementia is not a disease; it is the clinical presentation of disease.

There are many possible causes of dementia. Some of these causes are reversible, such as certain thyroid conditions or vitamin deficiencies. If these underlying problems are treated then dementia reverses and the person can return to normal functioning. However, most causes of dementia are not reversible. Rather, they are progressive, degenerative diseases of the brain. Alzheimer’s disease is one of these degenerative causes of dementia. In fact, it is the most common cause of dementia, accounting for 70-80% of all cases of dementia.

There are other less common degenerative causes of dementia, such as vascular dementia (also referred to as multi-infarct dementia), frontotemporal dementia, Lewy Body disease, and Chronic Traumatic Encephalopathy. But, again, the most common cause of dementia, accounting for approximately three-quarters of all dementia is Alzheimer’s disease. And, this disease is all too common, with approximately 5.3 million Americans currently living with Alzheimer’s disease. And, with increasing age, the prevalence of the disease increases, such that approximately 50% of people age 85 and older have the disease. It is important to note, however, that, although Alzheimer’s disease is extremely common in later years, it is not part of normal aging. And, for that matter, dementia is not part of normal aging. If someone has dementia (from whatever underlying cause) it represents an important problem in need of appropriate diagnosis and treatment by a well-trained healthcare provider.

Dementia Vs Alzheimers Disease

In a nutshell: dementia is a symptom; Alzheimer’s disease is the cause of the symptom. So, when someone is told they have dementia, it means that they have significant memory problems as well as other cognitive difficulties and that these problems are severe enough to get in the way of daily living. Most of the time, dementia is caused by specific brain disease, Alzheimer’s. Contrary to what some people may think, dementia is not a less severe problem, with Alzheimer’s disease a more severe problem. There is not a continuum with dementia on one side and Alzheimer’s at the extreme. Rather, there can be early or mild stages of Alzheimer’s disease, which then progress to moderate and then severe stages of the disease.