An Intro to Dementia… It’s Important so Don’t Forget!

This week’s topic is one that I have wanted to write about for a long time, but I haven’t been able to figure out how to approach it. As with many neuro/psych conditions in medicine, Dementia is so broad and nuanced that I was worried about not doing it justice when I write about it. That being said, I have decided how I will tackle this topic. It can’t be just one post; this will be part of its own series. There would not be enough clarity given if I tried to cram it all into one post. Today’s post will be a strong introduction to what dementia is and the different types of dementia.

What is Dementia?

Dementia is a broad term used to describe a group of diseases, which are characterised by similar symptoms, a syndrome. These symptoms include problems with memory loss, a decline in higher thinking and cognitive ability (which means processes like reasoning, planning, and understanding), and difficulty completing normal daily activities (1-6). The main types of dementia include Alzheimer’s Dementia, Vascular Dementia, Dementia with Lewy Bodies, and Frontotemporal Dementia. There is also a type called Mixed Dementia, which means a patient has more than one type at the same time. Alzheimer’s Dementia is the most common, accounting for 60-80% of cases of dementia.

Epidemiology

With the current global population getting older and older, we are seeing a steady increase in the yearly diagnoses of dementia. In 2021, there were 57 million people in the world diagnosed with dementia, with nearly 10 million new cases every year (3). It is estimated that in 2050, there could be almost 152.8 million people living with dementia (1). The usual age of onset for dementia is over 65 years old, which means the majority of the diagnoses come after this age. Sometimes, people can be diagnosed with dementia before this age. This is referred to as “Early Onset Dementia” (5). Dementia is currently the 7th leading cause of death in the world since 2019 (1,3).

Symptoms

As mentioned above, dementia is a syndrome, which means the different disease with overarching, similar symptoms which may be seen in all types of dementia. These symptoms are:

• Short-term memory difficulty – people may find that they are forgetting things more often or forgetting recent events; losing or misplacing things (2,3);
• Difficulty doing daily activities like paying bills, preparing and planning meals, remembering to go to appointments (3)
• Difficulty solving problems or making decisions (3)
• Problems following conversations or finding it hard to find the right words for things (3)
• Changes in mood and behaviour – for example, feeling more anxious, sad, angry, etc. (3)

Alzheimers Dementia

Alzheimer’s Dementia is the most common type of dementia, accounting for 60-70% of all diagnoses of dementia (4,7). It is a chronic, progressive disease which causes a general decline in higher-level thinking. The main symptoms seen in Alzheimer’s Dementia are memory loss, difficulty functioning in a work or social setting, problems talking or moving as easily as they once did, and personality change. Many patients experience a decline in their symptoms over 8-10 years (8).

Alzheimer’s dementia is caused by a buildup of proteins in the brain, which stimulates an inflammatory process. This inflammatory process releases lots of different chemicals and proteins, which lead to nerve injury and cell death (8). This eventually results in damaged areas of the brain that are involved in daily activity, memory and thinking. There are also other factors which can contribute to the development of Alzheimer’s Dementia, such as:

• Smoking – Chronic smoking has now been found to be associated with memory deficits and difficulty with learning. Some studies have also shown that smoking can cause widespread brain cell death and reduce brain mass, which means less information can be stored in the brain (9).
• Poor Sleep Quality – Sleep disturbances don’t necessarily cause Alzheimer’s Dementia; reduced sleep or poor quality sleep can exaggerate the symptoms of Alzheimer’s Dementia (9).
• Chronic Stress – Some studies have now identified that chronic stress can affect the cognitive process in negative ways, thus adding to the symptoms of Alzheimers Dementia seen in patients (9).

Vascular Dementia

Vascular Dementia is the second most common form of dementia (4), accounting for up to 20% of all cases (7). Like the other forms of dementia, Vascular Dementia demonstrates a progressive decline in normal cognitive function, such as decision making, daily activities, and concentration. Vascular Dementia is also associated with significant memory loss and motor difficulty, which means it is difficult to do normal things like walking, dressing, cooking, etc. Vascular Dementia is caused by brain cell damage, which arises from past strokes and other blood vessel dysfunction, which alters the blood supply to the brain (4,10). Whenever a blood vessel is obstructed or completely blocked and cannot supply blood to specific cells and parts of the brain, these parts die, and the brain mass decreases, which is what causes the dementia symptoms.

As this form of dementia is very closely related to cardiovascular causes, a lot of the risk factors of developing this form of dementia are closely aligned with the risk factors of strokes and heart attacks. These include risk factors such as (10):

• High blood pressure
• Smoking
• Diabetes
• Obesity
• High cholesterol
• Alcohol misuse
• Chronic kidney disease

Dementia with Lewy Bodies

Dementia with Lewy Bodies, or Lewy Body Dementia, is a very special type of dementia because it has more significant movement-related symptoms, which can also be seen in Parkinson’s Disease. This is because the causes of Parkinsons Disease are very similar to the causes of Dementia with Lewy Bodies (DLB). This type of dementia accounts for 10-15% dementia diagnoses (7), and it is often misdiagnosed as well, as its symptoms are similar to those of Parkinsons Disease. Some of the common symptoms of Dementia with Lewy Bodies are tremors, difficulty with swallowing, disrupted or poor sleep, hallucinations in sight or hearing, shuffling walking, which makes patients more prone to falling (4,11). Patients with this type of dementia struggle significantly with looking after themselves, as a lot of their motor functions are diminished quickly. Memory is less affected in this type of dementia, and thus contributes to difficulty with diagnoses.

Dementia with Lewy Bodies is also caused by a buildup of proteins in the brain, which leads to damage of the nerves and brain cells. The proteins that build up in this type of dementia are different to Alzheimers Dementia, however.

Frontotemporal Dementia

Frontotemporal Dementia is an interesting type of dementia because it causes significant personality change. In this type of dementia, the frontal and temporal lobes of the brain are mainly affected (7, 12). These areas of the brain are mainly responsible for learning, behaviour, personality and emotions. A lot of these areas are important in work and social environments, and so these symptoms can be noticed a lot earlier, in the pre-retirement ages. This may be why more people with this type of dementia are diagnosed before 65 years old (4). This type of dementia only accounts for about 2% of dementia diagnoses (7). Frontotemporal Dementia is usually associated with inappropriate social behaviour and a lack of inhibition, with behaviours like bingeing on food or being overtly sensual with the wrong people (4,12).

Mixed Dementia

This is a term used to describe two different forms of dementia showing up in the same patient. For example, if a patient has both Alzheimer’s Dementia and Vascular Dementia based on signs and tests, then they will be diagnosed with mixed dementia, and the classification of their mix will be documented. (4)

This is a very brief introduction to Dementia as a general topic, but I hope it has helped to water the ground for you. Later in the series, we’ll go through the different types of dementia in more detail, along with the types of tests and medications that are used to help manage the symptoms.

References:

1. BMJ Best Practice. Evaluation of dementia [Internet]. London: BMJ Publishing Group; 2025 [cited 2026 Apr 3]. Available from: https://bestpractice.bmj.com/topics/en-gb/242
2. Alzheimer’s Association. What is dementia? [Internet]. Chicago: Alzheimer’s Association; [cited 2026 Apr 3]. Available from: https://www.alz.org/alzheimers-dementia/what-is-dementia
3. World Health Organization. Dementia [Internet]. Geneva: WHO; [cited 2026 Apr 3]. Available from: https://www.who.int/news-room/fact-sheets/detail/dementia
4. Dementia UK. What is dementia? [Internet]. London: Dementia UK; [cited 2026 Apr 3]. Available from: https://www.dementiauk.org/information-and-support/about-dementia/what-is-dementia/
5. NHS England. Dementia [Internet]. London: NHS England; [cited 2026 Apr 3]. Available from: https://www.england.nhs.uk/mental-health/dementia/
6. Hafiz R, Alajlani L, Ali A, Algarni GA, Aljurfi H, Alammar OAM, Ashqan MY, Alkhashan A. The Latest Advances in the Diagnosis and Treatment of Dementia. Cureus. 2023 Dec 14;15(12)
7. National Institute for Health and Care Excellence (NICE). Dementia [Internet]. London: NICE; [cited 2026 Apr 3]. Available from: https://cks.nice.org.uk/topics/dementia/
8. BMJ Best Practice. Alzheimer disease [Internet]. London: BMJ Publishing Group; 2025 [cited 2026 Apr 3]. Available from: https://bestpractice.bmj.com/topics/en-gb/317
9. Safiri S, Jolfayi AG, Fazlollahi A, Morsali S, Sarkesh A, Sorkhabi AD, et al. Alzheimer’s disease: a comprehensive review of epidemiology, risk factors, symptoms diagnosis, management, caregiving, advanced treatments and associated challenges. Frontiers in Medicine [Internet]. 11:1474043. Available from: https://doi.org/10.3389/fmed.2024.1474043
10. BMJ Best Practice. Vascular dementia [Internet]. London: BMJ Publishing Group; [cited 2026 Apr 3]. Available from: https://bestpractice.bmj.com/topics/en-gb/319
11. Haider A, Spurling BC, Sánchez-Manso JC. Lewy body dementia [Internet]. StatPearls – NCBI Bookshelf. 2023. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482441/
12. BMJ Best Practice. Frontotemporal dementia [Internet]. London: BMJ Publishing Group; [cited 2026 Apr 3]. Available from: https://bestpractice.bmj.com/topics/en-gb/968