Ranking in the top ten highest mortality rates in upper income countries, killing more people than prostate and breast cancer combined, with no prevention, cure or way of slowing the symptoms, dementia has affected the lives of millions. According to the Alzheimer’s Society, there are currently 850,000 patients in the UK alone. With an ageing population, this figure is only set to increase, with an expected 1 million sufferers in the UK by 2025.
It’s a cruel disease. Symptoms progress through total memory loss, personality changes and lack of ability to care for oneself independently. Ultimately, it is fatal.
So why exactly is it taking so long to find any kind of cure for such a heartbreaking and widespread disease? Here are some of the headaches of dementia research, facing scientists at the moment:
Difficulties in diagnosis
‘Dementia’ is the umbrella term for a range of disorders. It can be caused by a variety of damaging effects on the brain, including Alzheimer’s disease, strokes and prion infections. Alzheimer’s is by far the most common cause of dementia, accounting for 50 – 80 per cent of cases. Rarer kinds include CJD which is caused by infectious particles called prions and fronto-temporal dementia which initially affects personality and behaviour more dramatically than memory. However, all of these causes amount to a pretty similar disease presentation, with the main symptom being memory loss.
For Alzheimer’s specifically, we lack any biomarkers for the disease. Biomarkers are molecules or biological elements that can be detected and used to attribute the presence of a disease. With so many different types of dementia and a lack of these biomarkers, it’s therefore often difficult to define the underlying cause of an individual’s sepcific illness and to progress with treatment. Often it takes years to come to a definitive diagnosis, which is not only frustrating but also damaging to the disease progression which worsens with age.
Lack of knowledge
At a cellular level, the disease has a few hallmarks. Notably, there are two kinds of protein accumulations known as ‘amyloid plaques’ and ‘tau tangles’ which have been associated with Alzheimer’s.While amyloid-beta is seen accumulating in plaques outside neurons, and tau accumulating as tangles inside neurons, both proteins are thought to build up in the diseased brain and prevent the neurons from firing, therefore preventing a signal from being transmitted. Since the neurons can’t communicate amy more, the cells die and the brain tissue shrinks dramatically. Great. We’ve got an identifiable cellular defect for the disease.
However, not all dementia patients will show these protein accumulations at autopsy. Likewise, some people who do have these protein accumulations never actually ever show any symptoms of dementia. So whether we’re looking at a cause or an effect, it’s hard to say. The underlying mechanism of the disease is still yet to be determined.
Current drugs don’t work
Currently, the primary prescribed medication for Alzheimer’s disease is a group of drugs called cholinesterase inhibitors. In dementia, there is often a dramatic loss in neurons that use a chemical called acetylcholine. This neuronal loss can be prevented by increasing the level of acetylcholine available.
Cholinesterase inhibitors work by preventing the breakdown of acetylcholine, thus increasing it’s concentration. The action of these drugs has been shown to slow or stabilise the progression of the disease in some patients. Similarly, other drugs are available which work on other chemical messengers, such as memantine which works on glutamate rather than acetylcholine.
But whilst these are the most effective drugs we have on the market, they still only work to improve symptoms for six to 12 months. Even then the efficacy of these treatments varies from individual to individual, and while patients are trying out all these drugs, they can often show really negative side effects and their symptoms may even deteriorate. Patients are often also prescribed antipsychotics for managing symptoms of psychosis that present with the dementia, however these offer little benefit and often shorten life expectancy.
Although these drugs have been shown to have a positive effect in many Alzheimer’s patients, we are still lacking effective treatment for other kinds of dementia such as vascular dementia.
With still more bad news on the finding drugs front, we’re lacking enough people for clinical trials. Seeing as we don’t have any defined biomarkers, and diagnosis in itself is difficult anyway, drug researchers struggle to find participants to take part in clinical trials of new drugs. No clinical trials, no new drugs.
Sometimes, science is difficult. As a patient or a carer it can be incredibly frustrating to see a lack of options for treatment.
Thankfully, attention to dementia research has increased hugely over the last few years. The British government recently pledged to more than double funding in Alzheimer’s research from £26 million in 2009/10 to £66 million in 2014/15. We’ve even been turning our attention to it here at the University of Exeter. This year we opened a Doctoral Training Centre with £5 million worth of funding and eight PhD students to work on the disease specifically. The project aims to bring together psychologists, geneticists, mathematicians, cell biologists and neuroscientists to look into how dysfunctional brain networks present in dementia form. So hang tight, a cure is coming. For now, we just might have to figure out some of the mysteries of the brain before we can get there.
- £26 million is spent per year on dementia research in the UK alone (enough to pay for the average energy bill of every household in the country).
- 48% of UK dementia sufferers receive a diagnosis, the rest never know. It is thought that there are 416,000 people living with dementia in England who haven’t been diagnosed.
- 80% of people living in care homes suffer from dementia or severe memory loss. In 2011, a whopping 291,000 individuals were living in residences such as these.
- 7 times more public money is given to cancer research than to Alzheimer’s research in the UK. In 2011 Alzheimer’s Research UK received £6,282,153 in voluntary donations.