Dementia – 12 years until a cure?

Earlier this month, London played host to the G8 Dementia Summit – a meeting of ministers, health experts and drug industry representatives, with the aim of developing a global strategy for tackling dementia. The event was a centrepiece of the UK’s Presidency of the G8, and David Cameron is keen for it to be remembered as the day ‘the global fight-back really started’.

The summit concluded with one stand-out, headline-grabbing announcement – the world’s 8 wealthiest nations committed to ‘the aim of trying to find a cure or disease-altering therapy by 2025’. This was underscored by the UK Government’s pledge to double its share of the money the UK spends on dementia research, from £66m in 2015 to £132m in 2025.

Other announcements include encouraging open access to all publicly funded dementia research, promises to develop an international plan for this research, and the appointment of an international envoy for dementia innovation.

These are all positive steps – a sense that dementia is becoming the most significant health crisis of a generation has been growing for some time, and Governments seem to be taking it seriously. Jeremy Hunt, the Secretary of State for Health, even went so far as to refer to taking action on dementia as ‘the litmus test for our generation of politicians’.

Our Government, like all other governments, is quite right to refer to dementia in such terms. The statistics speak for themselves – it is estimated by the World Health Organisation (WHO) that a new diagnosis is made every 4 seconds, while the Department of Health places the number living with dementia in the UK at 670,000, only 319,000 of whom have been diagnosed. The Alzheimer’s Society predicts that 135m people (up from 44m currently) will have dementia by 2050. There is also an economic burden – WHO estimated that global costs related to dementia ran to $600bn in 2010.

For a condition so concerning, remarkably little is known about it. What we do know can be confusing – it would be wrong to think of dementia as a disease, for example. The term actually refers to a group of related symptoms, associated with ongoing deterioration of the brain through death of its cells. It causes problems with memory loss, mental agility, language, and understanding. There are many types of dementia, including Alzheimer’s disease, vascular dementia, and dementia with lewy bodies. The causes of most of these are unknown.

There is currently no treatment available to halt or even slow the progression of dementia. Because of this, the current emphasis is on early detection. For example, it was revealed as part of the summit that a scan to detect accumulation of amyloid protein in the brain, a feature of Alzheimer’s disease, will be made available to a small number of patients on the NHS. This will be able to discount Alzheimer’s disease as a diagnosis.

In addition to this, Japanese researchers have recently developed a technique whereby a brain scan can reveal the presence of a protein called tau, also linked to Alzheimer’s disease. However, it is not known if these protein deposits, known as plaques, are a cause or symptom of the disease. Advice regarding prevention, as with many other conditions, relates mainly to exercise, eating healthily and so on. There is therefore a huge amount of complexity, and a dearth of knowledge, regarding dementia – this is one reason why the main announcement made at the summit should be met with scepticism.

Another reason, intrinsic to biology as a whole, is that research has a tendency to reveal further layers of complexity, meaning the rate of progress, especially with respect to finding effective therapies for diseases, is unpredictable. Bold predictions therefore often betray misplaced confidence.

A good example of such misplaced confidence (brilliantly related in Siddhartha Mukherjee’s The Emperor of all Maladies) is that of the Laskerites, a dogged group of cancer research advocates in the US. In the late 1960s, they drew inspiration for their dream of an all-out assault on cancer from the Apollo 11 mission. Referring to a ‘moon-shot’ for cancer, they launched an extensive campaign urging Congress to pass a bill. That effectively started the ‘War on Cancer’ through the creation of a National Cancer Institute with an unprecedented level of funding.

The time was characterised by the conviction that a universal cure for cancer was just around the corner. An advert in the Washington Post kick-started the campaign, using a quotation from Sidney Farber, one of the most respected oncologists at the time, which encapsulated this conviction – ‘We are so close to a cure for cancer. We lack only the will and the kind of money and comprehensive planning that went into putting a man on the moon’.

Needless to say, a universal cure was not, and is not, forthcoming. Since this time, scientists have come to realise that cancer, like dementia, cannot even be thought of as a singular disease – the field has grown infinitely more complex.

More recently, in June 2000, President Clinton held a press conference to mark the completion of the rough first draft of the human genome. The occasion was rife with unwarranted hyperbole. Clinton stated that knowledge of the genome sequence would ‘revolutionise the diagnosis, prevention and treatment of most if not all human diseases’, and that, as a result, his grandchildren may only know of cancer ‘as a constellation of stars’. When more detailed drafts of the genome were published, it became clear that it was far more complicated than had been anticipated. With the benefit of hindsight, statements like these seem wholly disproportionate to what had been achieved.

Both examples demonstrate why making bold assertions regarding scientific progress is generally inadvisable, however justified they may seem at the time. Promising a certain degree of progress by a specific date is entirely antithetical to the cautious, tentative nature of scientific enquiry. There is no way of telling where future research into dementia will lead, and throwing money at the problem is not guaranteed to produce results.

While the announcements made at the summit were undoubtedly well intentioned, both mentioning the possibility of a cure and setting a deadline were wrong – headlines aren’t worth falsely raised hopes.

Photo/Todd Jones