There is currently no "cure" for dementia. In fact, because dementia is caused by different diseases it is unlikely that there will be a single cure for dementia.
Huge strides have been made in understanding how different diseases cause damage in the brain and so produce dementia. And with increased funding over the past few years, there are now many more research studies and clinical trials taking place.
Although a cure may be some years away, there are some very promising advances.
Here are some of the areas researchers are working on and their findings so far.
Stem cells and dementia
Stem cells are "building block" cells. They can develop into many different cell types, including brain or nerve cells.
Scientists have taken skin cells from people with certain types of dementia, such as Alzheimer's disease, and "reprogrammed" them into stem cells in the lab. They've then triggered these stem cells to become brain cells.
By studying these cells, scientists have gained important insights into how the damage to the brain begins and how it might be halted.
These brain cells can also be used to test potential treatments at a very early stage.
Immunotherapy involves boosting the body's own defences to fight disease. It's one of the approaches that has been very effective in other diseases such as cancer.
In dementia, some studies have used vaccination against abnormal proteins that build up in the brain in Alzheimer's disease. Other studies have used monoclonal antibodies (manmade versions of immune system proteins) to target these proteins to slow the disease.
For example, monoclonal antibodies have been designed to target the amyloid protein, which builds up in the brains of people with Alzheimer's disease.
Several studies involving vaccination or monoclonal antibodies targeting amyloid have so far been unsuccessful. However, lessons have been learnt from these failed studies and a number of new clinical trials are taking place.
One such trial is the CLARITY study, which is measuring how effective the monoclonal antibody BAN2401 (lecanemab) is at preventing or delaying the very early stages of Alzheimer's disease.
More recent trials have shown promise and one treatment using an antibody called aducanumab is currently under consideration by the US Food and Drug Administration (FDA).
In addition, immunotherapies are also being used to target the tau protein in Alzheimer's disease and in some other diseases.
Another area being explored by researchers involves specialised immune cells in the brain called microglia. These cells are involved in clearing out debris from the brain.
In Alzheimer's disease, these immune cells appear to become overactive, which may be causing further damage to the brain. Current studies are trying to identify how to prevent this.
There is great interest in using gene-based therapies to target genes that can cause dementia, such as Alzheimer's disease or frontotemporal dementia.
These gene-based therapies are also being used to reduce the production of proteins involved in a dementia-causing disease, such as tau in Alzheimer's disease.
Developing new medicines to treat dementia takes many years and millions of pounds.
Repurposing existing drugs used for other conditions is another, often quicker, way of finding medicines to treat dementia.
Current medicines being explored as possible treatments for Alzheimer's and vascular dementia include those used for:
Identifying who's at risk of dementia
Experts know that damage to the brain caused by Alzheimer's disease can start many years before symptoms appear. If people at risk of Alzheimer's could be identified at an early stage, it is hoped that treatments could be offered that would slow down or even stop the disease.
A major study, called PREVENT, concentrates on people in their 40s and 50s to identify those who are at greater risk of developing Alzheimer's (based on family history and genetics). It aims to understand what is happening in their brains before symptoms appear.
Specialised brain scans, known as PET scans, have been developed to study two proteins (amyloid and tau) in the brains of those with Alzheimer's disease. The aim is to increase the understanding of the disease process, and also to identify those people who will benefit most from new drug treatments.
Although PET scans are sometimes used to help with a dementia diagnosis, these highly specialised scans are usually only available as part of clinical trials.
A number of different trials are now under way in people who are currently well but are at increased risk of Alzheimer's disease.
Prevention is important
Even if we find an effective cure for dementia, it would be better to try to prevent it happening in the first place.
Research has shown that the risk factors for heart disease and stroke – such as raised blood pressure, diabetes, obesity and smoking – are also risk factors for dementia. By modifying or changing these risk factors in mid-life, the risk of dementia could be reduced by up to 30%.
Join dementia research
There are dozens of dementia research projects going on around the world, many of which are based in the UK.
If you have a dementia diagnosis or are worried about memory problems, you can help scientists understand more about the disease, and develop future treatments, by taking part in research.
If you are a carer, you can also take part as there are studies into the best ways to care for someone with a dementia diagnosis.
You can sign up to take part in trials on the NHS Join Dementia Research website.