Emily Yoffe at Slate has a very accurate piece up on just how hard it is to make progress against things like Alzheimer's, Parkinson's, and other neurodegenerative diseases. The contrast with the hopes of patients - and the hype often surrounding the initial discoveries - is painful.
And we're back to that optimism/realism tightrope. On the one hand, I don't see any reason why we shouldn't be able - eventually - to stop such conditions in their tracks, or to keep them from starting in the first place. (Reversing the damage once it's done, though, is much more of a stretch, to me). But on the other hand - sheesh, we really, really have a lot to learn about these things. The likelihood of any one discovery being the key breakthrough is small - nonzero, but small. So in the long term, I'm an optimist, but in the short term, well. . .every little bit helps, and most of the bits are going to be little.
That's not the sort of news you want to give to someone suffering from these conditions, of course. That desire for encouraging news, along with plenty of other good intentions (and a few not-so-good-ones) leads to the cycles of hype that we've seen over and over. Stem cell research is a perfect example. There really are huge possibilities there, extraordinary ones. But our level of ignorance is also extraordinary. And to go out and make claims that we're going to be able to cure X and reverse Y soon, based on our present knowledge, is just plain irresponsible.
But plenty of people do just that - politicians, headline writers, and others. And then people who only know what they see in the news wonder where things went wrong, and how come these wonderful cures haven't arrived yet. It all makes explaining the real situation that much harder.
It's not like the real situation is even all that terrible. As I said above, I really do think that these diseases - and many others - are eventually going to be treatable. No one likes that word "eventually", though.