Dementia is an umbrella term that is used to refer to a group of diseases that have broadly similar symptoms but different causes. The most common symptoms include memory loss, difficulty performing everyday tasks, problems with language and communication, disorientation in time and place, poor or decreased judgement, changes in mood, behaviour or personality. Of the diseases that cause dementia, the most common are Alzheimer’s disease, Vascular Dementia, Lewy Bodies Dementia and Fronto-temporal dementia.
There is often confusion and misunderstanding about what the difference is between the terms dementia and Alzheimer’s disease. However, there is a distinct difference. Dementia is the term that is used to refer to a set of symptoms including impairment in memory and thinking, which interferes with a person’s ability to do things that he or she was previously able to do. Alzheimer’s disease is the most common cause of dementia, and because of this it is frequently confused and equated with the term dementia. However, there are many other causes of dementia including Vascular Dementia, Lewy Bodies Dementia and Frontoteremporal dementia. Less common causes of dementia are Parkinson’s Disease, Karsakoff’s syndrome, HIV/AIDS and Creudzfeldt-Jakob disease, all with a more or less distinct symptomatology. Dementia is therefore an umbrella term that is used to refer to the group of diseases, including those mentioned above, that have broadly similiar symptoms but different causes.
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The material was created by TCD, through the NEIL Programme at the Institute of Neuroscience with support from GENIO. 2014 The Provost, Fellows, Foundations Scholars, and the Ohter Members of Board, of the College of the Holy and Undivided Trinity of Queen Elizabeth, near Dublin. Persmission to use this material was granted by TCD which reserves all rights in the materials.
Alzheimer’s disease and the other dementias are not a normal part of ageing. Dementia is age-related, which means that most people who develop dementia are aged 65 years and older. After the age of 65 years the likelihood of developing dementia doubles about every five years, but, most older people do not develop dementia. Many people experience some minor forgetfulness and slowing of the thought processes as they age; this can lead to common annoyances such as misplacing keys, forgetting a person’s name or the name of a book they’ve read recently. When memory loss is not caused by any underlying medical condition, it is known asage-related memory loss. Whilst frustrating, this is considered a part of the normal ageing process and is not a cause for concern. However, memory problems related to brain diseases like Alzheimer’s disease and the other dementias are different. When it comes to memory loss it is important to be able to distinguish between age-related memory loss and memory loss that may be associated with dementia. Examples of the ways to distinguish between these are given below, but in general, memory problems become a concern if they begin to disrupt day-to-day life. With dementia it is not just memory that is affected, but also the way a person thinks, speaks and does things.
The short table below gives some examples of age-related memory problems and memory loss that may be related to a dementia. It is important to consider whether, for example, the person has always had a bad memory for names. If the memory problem you are concerned about does not represent a change in ability it is very unlikely to be a symptom of dementia.
Age-related memory loss
Memory loss associated with dementia
Not being able to remember an acquaintance’s name
Forgetting that you saw them a couple of days ago
Forgetting where you left things that you use regularly such as your glasses or keys or other items
Forgets what an item is or what it is used for or puts items in inappropriate places, e.g. kettle in the fridge
Occasionally forgetting appointments but remembering later
Forgets important events, loses sense of time and does not know what day it is
Occasionally has to search for the right word
Struggles to find the right word and calling things by the wrong name
Dementia is a common condition and people who have a family member with dementia are sometimes concerned that they will inherit the condition. A person may develop dementia without anyone else in the family having been affected. This is called “sporadic” dementia, and the majority of cases of dementia are sporadic. The cause of the sporadic form of dementia is not fully understood, but the likelihood of developing dementia depends on the person’s age acting together with the lifestyle and the genes that the person has. Alzheimer’s disease is the most common form of dementia and sporadic Alzheimer’s disease is very common. The majority of cases of Vascular Dementia, the second most common form of dementia, are also sporadic.
Sometimes dementia runs in families because of genetic mutations or faults. Early onset Alzheimer’s disease, (where the disease affects people at a younger age usually in their 40s or 50s) and some cases of Fronto-temporal dementia can be caused by genetic mutations and passed down in families, in which case they are known as genetic or familial dementia. In contrast with somatic dementia, familial dementia is very rare.
Because dementia is quite common, it is not unusual for people to have a family history of dementia. But, having a family history of dementia does not necessarily mean that there is genetic or familial dementia in the family. However, the lifetime risk of developing dementia is slightly higher for people who have a family history of dementia compared with people in the general population.
Whilst genes can play a role in the development of dementia, it needs to be remembered that, for the vast majority of dementias, our genes are only one factor affecting our likelihood of developing dementia. The likelihood of developing dementia is also influenced by a number of factors related to lifestyle including blood pressure, mood, physical exercise, weight, smoking, drinking, cholesterol, diet and cognitive activity. There is excellent evidence that a healthy lifestyle can help to reduce the risk of dementia. Based on this evidence, In-MINDD is developing online supports to help people in midlife with one or more of these factors to adopt and adhere to lifestyle changes. Simple lifestyle changes that you can make to enhance your brain health and reduce your risk of developing dementia include:
Gingko biloba cannot be recommended for the purposes of preventing or delaying the onset of dementia. Ginkgo biloba is an extract from the ginkgo tree. It contains several compounds that are thought to have both antioxidant and anti-inflammatory properties and may have positive effects on cells within the brain and the body. Ginkgo biloba has been used for centuries in traditional Chinese medicine. Whilst it has been widely promoted as a memory enhancer, there is a substantial body of evidence that Gingko biloba extract does not prevent dementia. Recent studies have shown that gingko biloba is no better than a placebo in preventing or delaying the onset of Alzheimer’s disease or other dementia. The most important of these studies are two long, large studies: The Ginkgo Evaluation and Memory (GEM) Study (http://nccam.nih.gov/research/results/gems) conducted\r\nin the US, and the GUID-AGE study, conducted in Europe. Hence, there is not enough information available to recommend the use of ginkgo biloba to prevent or delay the onset of Alzheimer's disease or other forms of dementia.
Heavy drinking has both immediate and long-term harmful effects on the brain and current evidence suggests that people who drink heavily over a long period have an increased risk of developing Alzheimer’s disease or other types of dementia. Long-term excessive alcohol consumption can even lead to a condition called alcohol-related dementia. You do not need to be an alcoholic to have a higher risk of developing dementia. Drinking more than the weekly recommended levels of alcohol on a regular basis increases your risk. Binge drinking (the consumption of more than six standard drink in one session) in midlife is also associated with an increased risk of dementia. Most studies have, however, focused on the protective effects of low-to-moderate alcohol consumption, which may help to protect your brain and reduce your risk of developing dementia. This does not provide a reason for anyone to take up drinking, if s/he doesn’t drink. But, if you do drink alcohol it is important to do so in moderation. This means drinking within the recommended levels. Drinks should be spaced out over the week and not consumed in one sitting.
Currently, there are no indications of a relation between autism and the risk of developing dementia.
A large number of studies show that people experiencing depression have a slightly greater chance of developing dementia in later life than those who do not have depression. It is estimated that at the age of 65 a person's risk of developing dementia is 1%. In comparison estimates are that for people with depression there is a slightly higher risk of 2%. It is still not known why people with depression have a slightly increased chance of developing dementia.
Whilst depression can play a role in the development of dementia, it is important to remember that, for the vast majority of cases, our mood is only one factor affecting our likelihood of developing dementia. Age is the strongest risk factor for dementia. After the age of 65, the likelihood of developing dementia doubles about every five years, but most older people do not develop dementia. Similarly, if a person experiences depression, this does not mean that they will develop dementia in later life.
There are steps that we can take to improve our mood. The mood page of the In-MINDD support environment provides tips on things you can do to improve your mood and links to websites of organisations that provide information and supports for people with depression. On the ‘Useful Apps’ page you will also find some Apps that may be helpful in supporting people with depression.
The likelihood of developing dementia is also influenced by several factors related to lifestyle including blood pressure, high cholesterol, physical exercise, weight, smoking, alcohol consumption, diet and cognitive activity. There is excellent evidence that a healthy lifestyle can help to reduce the risk of dementia. Based on this evidence, In-MINDD has developed online supports to help people in midlife with one or more of these factors to adopt and adhere to lifestyle changes. Simple lifestyle changes that you can make to enhance your brain health and reduce your risk of developing dementia include:
We carry genes that can lead to specific diseases. Having the genes for a disease means that we have a greater risk of developing the disease compared to individuals who do not carry those genes. But this does not mean that we will develop this disease for sure. The expression of the disease (gene expression) depends on many factors related to the individual and his/her environment.
It could be useful to know if we carry a ‘familial disease’ which has a great chance of expression (dominant disease), especially if a cure does exist. In contrast, is it not very useful to know that we are carrying a gene that could lead to a disease (without certainty) and for which there is no cure yet.
Knowing our genome is useful in certain circumstances: diseases whose signs are not clear and symptoms seem to indicate that it might be a genetic disease, a serious family illness that impacts on health at birth, and other exceptional circumstances.
In Alzheimer's disease, the dominant familial form is rare (5%), and largely affects people at a younger age (before 65). It is possible to establish clinically if it is a familial form, without genetic testing. For other types of dementia, research is ongoing. Some genes are thought to predispose a person to Alzheimer's disease, but having those genes does not mean that the person will definitely develop the disease. That is why it is important to act on the MODIFIABLE factors: we cannot change our genes, but we can work on factors that can affect their expression.