To know or not to know: is that the question?

Hamlet famously brooded about the pros and cons of existence, but in our age of science the pros and cons of knowledge, especially partial knowledge, provide a comparable dilemma.

Triggering our post today is another very fine story by science reporter Gina Kolata in the NT Times, on early diagnosis of Alzheimer's Disease (AD).  This can be a devastating disease, but there is currently no cure or effective treatment.   That means that an early diagnosis can devastate people, and their families, for more years than the disease actually will do itself.  So the question is asked whether the early diagnosing test that now can be done, should be done.

One can't control whether he or she exists, though one certainly can end that blissful state.  But we can control information....or can we?  Many argue that once information, or the ability to gain information exists, there is no corresponding kind of data suicide that is realistic.  Someone, somewhere will pry Pandora's box back open, so the argument goes.

This is, however, not just an argument about the realities of the world, but also an argument of convenience by individuals who want to pry the box open for self-interested reasons.  Often, as in the case, say, of stem-cell or GMO plant research, this is for commercial reasons.  Others are amoral and simply want to know, or like to pry, or don't think information can be bottled up.  Science itself provides answers to the empirical questions, but not these social, ethical, or moral ones.

We certainly do have limits on what can be done.  Crimes are defined behavioral prohibitions in society in general.  In science, we have research review boards and some laws that attempt, at least, to regulate what is allowed.  You cannot get approved to pull people's fingernails out in order to test their pain thresholds, even if somehow you could get volunteers who were informed about the nature of the study.  You cannot secretly sterilize psychiatric patients to see if it affects the sexual content of their dreams.  You can do almost anything to insects or fish, on the incredible posturing that they feel no fear, but you can't euthanize a chimp you've used for research.

You can't build an atomic bomb in your basement, or park a functioning army tank (loaded with ammo) in your driveway.

So arguments that we can't control what is done in research are simply disingenuous.  Instead of such posturing to justify anything goes because it can't be stopped, the discussion should be on whether we should, as a society, allow or allow payment for, various aspects of medical practice.

Partly this should depend on whether the procedure can harm the subject more than it can help.  Partly it should ensure that it is entirely informed and voluntary.  But 'informed' is a critical part of the story.  How well does the test actually predict the future disease?  How much imprecision is tolerable?  According to the Times story, the uncertainties are still great.  And family history is itself a (free) partial and informative predictor.  And, of course, as you age you're going to get something unpleasant, and mental fog is a common part of that.  Should we test for every disease of old-age decades in advance?

And there are practical implications: AD screening is very costly, may be quite unpleasant (spinal taps) and some tests are intrusive.  Anticipatory treatment based on a screening result can involve very costly interventions (as we know from mammography, PSA, cholesterol, glucose, and blood pressure testing).  Those costs are spread across insurance pools, so we all pay for them one way or another.

We have clear precedent:  There are pretty reliable tests for Huntington's Disease, but many who know they are in affected families and are potentially at risk choose not to be genotyped.  At the same time, genotyping is available if they want it.

Hamlet's internal debate is relevant to this, as to existence itself:

To know or not to know.  
Whether 'tis nobler in the mind to suffer  
The slings and arrows of outrageous fortune,
Or to take arms against a sea of troubles,
And by opposing end them? To die: to sleep;
No more; and by a sleep to say we end
The heart-ache and the thousand natural shocks
That flesh is heir to, 'tis a consummation
Devoutly to be wish'd.