This is probably the most common question I’m asked by my readers, so I decided to devote an entire article to clearing up the confusion. Doctors and scientists often throw around words like “dementia,” “Alzheimer’s,” and “mild cognitive impairment” without making it clear what the difference is between them. Understanding what each of these terms mean is important for being able to interpret articles and recognize how scientific findings may apply to you.

Let’s start with dementia. Dementia itself is actually not a disease, but a set of symptoms. The most well-known dementia symptom is memory loss, but it also includes other things such as difficulty communicating, impaired attention, poor judgement, and a decline in visual perception.

Dementia symptoms can be caused by many different diseases. The most common cause of dementia is Alzheimer’s disease, which makes up around 60% of all dementias. However, many other diseases can cause dementia, including Parkinson’s disease, vascular dementia, frontotemporal dementia, and Lewy body disease. Dementia is often referred to as an “umbrella term” for a range of symptoms than can be caused by multiple diseases.

I like to use an analogy to make this distinction a bit clearer. Think of Alzheimer’s disease like the flu. These are both diseases with a particular cause. Now think of some of the symptoms of having the flu: congestion, chills, nausea, and so on. There are many different diseases that can cause these symptoms, like a cold or sinus infection. In the same way, there are multiple diseases that can cause dementia symptoms.

To put it another way: everyone with Alzheimer’s disease has dementia, but not everyone with dementia has Alzheimer’s disease.

Now, there’s a third term you may have also heard thrown around: mild cognitive impairment, or MCI. It’s characterized by memory problems that are noticeable but not severe enough to interfere with daily life, such as forgetting appointments, losing your train of thought, and having trouble with planning or organization. Some people with MCI later progress to Alzheimer’s disease or other dementias, while others do not. Around 20% of adults over age 65 have MCI.

So there you have it! To summarize:

Dementia is a set of symptoms that include memory loss, impaired attention, and and poor judgement.

Alzheimer’s is one of several diseases that can lead to dementia symptoms.

Mild cognitive impairment is a less serious memory problem than can, but does not always, progress to dementia.

Hopefully that helps to clear up some of the confusion surrounding these three terms! As always, feel free to comment or send me a message if there are any other topics you’d like me to explain.

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