Premodern umpire: "I call 'em as they are!"
Modern umpire: "I call 'em as I see 'em!"
Postmodern umpire: "They ain't nuthin' 'til I call 'em!"
In the current Psychiatric Times Ronald Pies, M.D. pooh-poohs the proposed diagnosis of "hypoactive sexual desire disorder" (I can't find an online link for it yet). I hold no brief for that particular problem (sounds like enhancement to me), but I found his article notable for his suggested approach--the "desert island test"--to defining mental disorder.
Specifically, Pies maintains that a disease is one which would cause both distress and incapacity with respect to even the kinds of basic survival functions needed for castaway solitude. Even apart from the objection that such isolation would provoke serious emotional problems in most people, it seems like an awfully restrictive model. For all mental disorders are exquisitely sensitive to stress and crucially contingent upon context, and for Homo sapiens, stress and context are primarily interpersonal. I can think of any number of severe schizophrenics, bipolar folks, and of course substance abusers who--again, if they could tolerate the loneliness--might function surprisingly well on a desert island.
Pies's model is an example of a common desire to clarify the bounds of psychiatric diagnosis by distinguishing endogenous from "merely" situational syndromes; the difficulty is that people cannot be fully understood apart from their situations. But it brings to mind the notion of mental disorder as one that impairs evolutionary fitness; this is an idea that aims to get at some primal ideal of (healthy) human nature, one free of all the dross of contemporary cultural pressures and expectations. Again, the problem is that human beings evolved as deeply social creatures, so the impact of social and cultural context is inextricable from human nature.
In an effort to dismiss mere cultural consensus as a source for psychiatric diagnosis, Allan Horwitz and Jerome Wakefield write in The Loss of Sadness: How Psychiatry Transformed Normal Sorrow Into Depressive Disorder:
Moreover, when concepts of disorder are equated with whatever conditions are called disorders in a particular group, the possibility of scientifically evaluating and critiquing these concepts is lost. Also lost is the commonsense understanding that a culture could be wrong in its judgments about disorder. For example, the Victorians were wrong in believing that masturbation and female orgasm were disorders, and some ante-bellum Southerners were wrong in holding that runaway slaves were suffering from a mental disorder. But if disorders are just culturally relative conditions, then we cannot explain why these judgments were wrong, because those diagnoses did indeed express the values of their times. (p. 219)
This seems like a fine bit of epistemological panic to me, as if the lack of scientific evidence leads inevitably to mere relativism. What if diagnostic guidelines are rooted not in science, but in the same kind of rigorous and argued (but not incontrovertible) consensus that prevails in, say, ethics and law? After all, slavery and sexism also expressed the values of the 19th century, but we can firmly believe and argue that they were deeply wrong. Diagnostic guidelines are in fact made up as we go along, but only in the same way that the courts "make up" the law as they go along, that is, based on reasoning and rooted in prevailing cultural values. In fact, psychiatrists are something like judges, applying precedent to the circumstances of a unique case. Similarly, an umpire's calling of balls and strikes is inherently subjective, but it is a practice situated in accepted guidelines for the strike zone.
Attempting still to keep diagnosis tidy, Horwitz and Wakefield write:
Problematic mismatches between human nature and current social desirability such as adulterous longings, male aggressiveness, or becoming sad after losses are not in themselves disordered. For example, it may be fitness enhancing in our culture not to have tastes for fat and sugar, but that does not mean that people who have such tastes are disordered; that is how we were designed to be, due to conditions that existed when we were evolving. (p. 220)
They seem to imply that such entitites as ADHD, obesity, and substance abuse are therefore cultural pathologies or toxins, having nothing to do with individually diagnosed disorders. However, they immediately go on to qualify this:
However, sometimes environmental conditions that are too different from what is evolutionarily expected can produce real depressive disorders because people were not naturally selected to function in such settings. Modern warfare, for example, leads many soldiers to develop mental disorders that persist far beyond the immediate combat situation because the human brain was not developed to function under such conditions. (p. 220)
It is hard to see how a situational background like war is more productive of individually diagnosable disorders than, say, the easy availability of abundant calories. Is the implication that obesity is merely a personal choice, whereas trauma is not?
There is a real biology of differences of emotional responsiveness, interpersonal relatedness, stress resilience, etc. just as there is a real physics of a baseball's trajectory over the plate. Technologies of biology and physics can modify these processes with greater or lesser success. But what we define as pathology or as balls and strikes can never be a matter of science; it is a matter of reasoned consensus.
Human biology and human nature are not equivalent concepts; human nature also includes culture and consciousness and is therefore self-modifying and self-questioning. The laws of biology are universal, but the contents of biology--what kinds of organisms actually exist at any given time--are contingent. Similarly, there are sociological "laws" of diagnosis inasmuch as pretty much all human cultures have implicit or explicit categories of health vs. sickness, but the contents of those categories may justifiably vary across times and places. Diagnostic categories are not entities we discover, they are entities we decide on.
Why do people keep trying to ground nosology in science? Perhaps because ours is a fractious and often fractured culture, such that consensus is very difficult to achieve, and in psychiatry there is no body with the authority of the Supreme Court. Some diagnoses are straightforward--severe and persistent mental illness is no more conceptually ambiguous than, say, murder (which isn't to say there is no ambiguity at all). Views of the proper bounds of ADHD or depression, in contrast, may vary as much as if not more than views of abortion or gay marriage--in all of these cases there is no account that is eternally or "scientifically" valid; there are merely competing claims of harm vs. an ideal of the good.