If people over 70 or 80 years of age notice memory loss, the concern is justified that it could be Alzheimer's disease or another form of dementia. But what about people who are 60, 50, or even just 40 years old? These age groups are certainly too young for Alzheimer's disease or dementia, aren't they? Not necessarily.

‍

‍

Around 10% of Alzheimer's disease starts before the age of 65

Of the more than 55 million people living with dementia worldwide, around 60 to 70% have Alzheimer's disease. And of the 33 to 38.5 million people with Alzheimer's disease, 10% began to notice memory loss or other symptoms before age 65. Alzheimer's is in fact the most common cause of early-onset dementia. A recent study from the Netherlands found that of people with a known classification of their early-onset dementia, 55% had Alzheimer's disease, 11% vascular dementia, 3% frontotemporal dementia, 3% Parkinson's dementia, 2% had Lewy body dementia and 2% had primary progressive aphasia.

‍

‍

Early-onset dementia is rare

Dementia at a young age (by definition beginning before age 65) is rare. A Norwegian study found that early-onset dementia occurred in 163 out of 100,000 people, i.e. less than 0.5% of the population. People who are under 65 and notice problems with their memory therefore have a 99.5% chance that the cause is something other than dementia.

‍

However, there are a few exceptions here. Because they have an extra copy of the chromosome that carries the gene for amyloid in Alzheimer's plaques, more than half of people with Down syndrome develop Alzheimer's disease early on. Other genetic abnormalities in the family may also cause Alzheimer's disease to break out in earlier years. However, those affected would know whether they are at risk because one of their parents has Alzheimer's disease at a young age.

‍

‍

How does early onset Alzheimer's disease differ from late-onset disease?

First of all, you should be aware that just as no two people are the same, no two people with Alzheimer's have the same symptoms, even if the disease starts at the same age. However, there are some differences between early-onset and late-onset Alzheimer's disease.

‍

People with typical, late-onset Alzheimer's disease that starts at age 65 or older show a combination of changes in thinking and memory that are attributable to Alzheimer's disease, as well as changes that are part of normal aging. The parts of the brain that change the most during normal aging are the frontal lobes. The frontal lobes are responsible for many different cognitive functions, including working memory — the ability to keep and process information in your head — and insight into the problems you have.

‍

This means that people with early-onset Alzheimer's disease have relatively isolated problems with their episodic memory, i.e. with the ability to form new memories to remember recent episodes of their lives. People with late-onset Alzheimer's disease show problems with episodic memory, working memory, and insight.

‍

‍

Depression and anxiety are more common in young onset Alzheimer's disease

On average, people with late-onset Alzheimer's disease show more impairment of their cognitive abilities and everyday functions than people with early-onset Alzheimer's disease, at least at the onset of the disease. However, as cognitive ability is also impaired, people with late-onset Alzheimer's disease do not notice these difficulties as clearly.

‍

In contrast, patients with early-onset Alzheimer's disease are often depressed about their situation and anxious about the future because of their greater insight — a finding recently confirmed by a group of Canadian researchers. And as if Alzheimer's disease at a young age didn't trigger enough depression and anxiety, recent evidence suggests that the disease is progressing faster in people with early-onset Alzheimer's disease.

‍

Another tragic aspect of Alzheimer's disease, which starts at a young age, is that it affects people in the prime of their lives and affects families more than a late-onset illness. Teenage children and young adults are no longer able to orient themselves to their parents. People who have previously looked after the children in the household must now also look after their spouse — perhaps in addition to caring for an aging parent and working full time.

‍

‍

What else could cause memory problems at a young age?

The most common cause of memory problems under 65 years of age is lack of sleep. Other causes include perimenopause, drug side effects, depression, anxiety, illegal drugs, alcohol, cannabis, head injuries, vitamin deficiencies, thyroid disorders, chemotherapy, strokes, and other neurological disorders.

‍

Finally, here are some things anyone at any age can do to improve their memory and reduce their risk of dementia:

Perform aerobic exercises.

Eat a Mediterranean diet.

Avoid alcohol, cannabis, and drugs.

Get a good night's sleep.

Participate in social activities.

Do new, cognitively stimulating activities, listen to music, practice mindfulness and maintain a positive attitude.