Conclusions

The past twenty years have seen an explosion of knowledge in our understanding of the human brain, especially in the field of neurodegenerative illnesses such as Alzheimer's. We are now in a position to describe accurately the pathology of the brain and in many instances relate this to abnormal biochemical and molecular reactions. This understanding has been enhanced and further clarified by advances in human genetics which have pinpointed gene mutations that strongly predispose carriers to early-onset Alzheimer's and increase the risk of the development of Alzheimer's in old age. Screens for the identification of carriers of these genes will enable preventive strategies to be appropriately applied once disease-modifying medicines become available.

The search for effective medicines has benefited enormously from this new knowledge. The approaches reviewed in this booklet demonstrate impressive scientific creativity and a bewildering diversity of approaches. So rapid has progress been that it is hard to believe that the first medicine introduced specifically for Alzheimer's became available as recently as 1993. Since then, further products that act to conserve acetylcholine have become available and have been shown to stabilise or, in some cases, to reduce mental decline.

Of course, such medicines are only a first step and not the final goal, and newer treatments are now being researched. The ultimate aim must be to develop medicines that prevent the brain changes that seem to underlie the functional decline. Among these are compounds that can protect the brain from damage by reactive oxygen or inflammation, can stimulate nerve regeneration, or even ameliorate the formation of neurofibrillary tangles or amyloid plaques. There are now strong grounds for believing that compounds that act to prevent or remove amyloid plaque will modify the progression of the condition and retain a better quality of life for a longer time for thousands of elderly and not-so-elderly people. In the next few years, several such medicines should enter clinical trials, but only then and with extended experience will we know if we have reached the beginning of the end for Alzheimer's as a scourge of older people, or merely the end of the beginning.

Perhaps the most exciting research over the past two to three years has related to a potential Alzheimer's vaccine. Using specially bred mice which carry a human gene causing them to develop amyloid plaque and show memory and learning problems, it has been shown that vaccination can substantially prevent plaque formation and improve mental processes. This is now in the early stages of assessment in humans, but by the very nature of Alzheimer's, it will be some years before a final answer is available. If the results are positive, we would be justified in believing that this awful illness might be truly preventable.

In the meantime, it is important to recognise the great demands placed on everyone trying to cope with Alzheimer's and to improve the coordination, access and range of services available to them. If that is done, a substantial burden of human misery can be lifted while we eagerly await the outcome of current medical research.