Well, the vested interests are at it again. Here's a story that reports evidence based largely on brain scans that 2-3 times more Americans will be diagnosed with Alzheimer's dementia than currently. The idea is that there are early signs of the diseases in aging, but not yet old, adults and these can be detected by brain scans.
Dementia is an awful disease that plagues a population, like ours, in which so many live to such old ages. Prevention or even adequate treatment would be life-changing for its victims. A couple of drug trials are under way, and there are various other approaches being tested--it's in the news almost every day. This is the good side.
The down side is that the health care system is already badly overstressed financially, and with an aging population this will get much worse, as we all know. Alzheimer's will require 'maintenance' therapy--not just a single vaccine or week of pills, but treatment that goes on for life. And early diagnosis means years -- decades -- of this or other therapies. And making the new diagnosis requires expensive tests like brain scans. So guess who's in favor? The industry that will supply these therapies.
Here's a genuine conflict of interest. As long as we live long lives, we should hope to make those lives worth living, and controlling dementia would be a great contribution to that. But how can we afford it, and should we allow this to be a huge financial bonanza to some corporate entities whose natural interest will be to push the amount of treatment ever upward?
There's no easy answer. Dementia is complex and it's not clear whether the genetically based pharmaceutical approaches to it will work. If they don't, diagnosing people decades before they show symptoms will lead to a lot of essentially over-treatment and expense, not to mention great anxiety.
There's something else that we can predict: as diagnostic approaches increase, so will diagnosis--and so will the heterogeneity and complexity of the 'disease'. Getting old involves changes and the more we look the more we'll find. Even if "Alzheimer's" were a refined diagnosis, other brain pre-disorders will be found. Each will then be used to justify extensive research projects, treatments, and the like.
It's part of the conundrum that Nature throws our way, in which there are usually no easy answers.