An indicator of the nature of science is its standard texts. A text is usually a 'safe' work, a statement of core knowledge that is solid and reliable. Main facts and theories in texts are usually very slow to change, and they should be.
In medicine, things are similar. A medical manual, sometimes called a vade mecum, is a ready reference for diagnosis or treatment. It should be the solid underpinning on which daily, immediate decisions are made, solid knowledge rather than research speculations or tentative ideas. But often things are not that way, and it provides an important lesson for some areas of science that have important policy implications relevant to this blog, and our concern here with the nature of biological and genetic knowledge.
The NYTimes has a story on a forthcoming and long-awaited Diagnostic and Statistical Manual of Mental Disorders. According to this article, major revisions will be made in diagnostic criteria, with all that implies about ideas concerning underlying cause--and highly relevant both to accepted medical treatment, health-care costs, and the interpretation of scientific studies.
If the classification of mental disorders is being revised in a major way so that tomorrow's diagnosis and treatment are greatly different from today's, yet without major new 'facts' about mental illness having been discovered, what does this say about the state of knowledge in this field? Largely, it says that knowledge is on very shaky grounds. And it raises the important question: should we believe this new version?
We noted in a recent post that we are all, even scientists, often even within our own field, helpless in the face of a barrage of facts in the huge research literature. We must trust the integrity of research. When research is distorted for political opportunism (as in the anti-climate change luddites) or personal gain (as in conflicts of interest in medically or pharmaceutically related research), we are all losers, lost in seas of uncertainty.
In this case, however, the lost feeling comes not from a sense of fraud or conflict of interest, but in a sense that the field itself is a sea of uncertainty. Its guides represent fragile current knowledge, often argued out in the journals on the basis of belief rather than fact because the facts are so elusive. GWAS mapping results (or, rather, their basic lack of definitiveness) for psychiatric disease, presented in an era that accepts genes as metaphors for all types of causation in life--and society--do not provide clear guidelines for understanding.
We must have faith in the literature, but who can, in this area? There is clearly a need for more research on the brain, but also perhaps on the society that judges and evaluates behavior. Because this is part of the picture. If parents, teachers, doctors, therapists, drug companies, hospitals, schools, retirement centers, and the like all have a stake (often financial but sometimes even psychological) in decisions then it is hard to see how we can emerge from the forest of uncertainty.