I've alluded to psychiatric classification as the assembly of a moth or snail collection, each sample arrayed according to size and color. Current practice can be unwieldy when you consider digital traits; fortunately, nature often gives us a mix of analog regulators under many digital features, regulators that may be independent of any particular characteristic. Thus, we can sort a collection of shells according to analog characters even while puzzled by the digital jumps. Charles started us with incremental change; we continue that tradition.
Psychiatric diagnosis -- another sorting that we do of each other into varied classes -- currently has 410 boxes, a spot for each one of us and perhaps multiple possibilities for some.
Samuel Barondes, Harvard Mental Health Letter, November 1998, "Will Genetics Revolutionize Psychiatry?" concludes that it surely will. I've foreseen that we may supply a toenail at birth and provide a career map of our vulnerabilities to varied misfortunes of varied intensities and durations as well as a map of adverse reactions, medication of choice, and responsiveness to social alliances as a part of our coping systems.
Multiple genes offer more stable traits than single-gene mechanisms; polygenic foundations also imply a greater range of "normal" variability in a trait at the same time they assure that it will be present to at least some degree. Thus, we have a model of genes that handles environmental input and has enough flexibility to encompass vexing data such as the child of a bipolar parent having 1 chance in 10 of developing BPD of the identical twin of bipolar having at least? only? a 60% chance to get same diagnosis.
DNA scans may become standard practice at the time of a psychiatric interview. One motivator will be that of confirming a diagnosis or choosing between several possibilities. Psychiatry, however, is a mechanic's enterprise like the rest of medicine; gene scans will probably be more valued for their help in selecting suitable medications than for their diagnostic contributions.
Psychiatric classification could well move from an infancy wherein disorders are classed by behaviors (sorted consistently with the observer's psychological adaptations for making classifications) through its current stage of sorting illness by the medications that work, and into genetic trees. All of which means that a lot of palliative treatment can occur without considering hierarchies, evolution, and whether we are having difficulties with mechanisms derived in our lizard stage of ontogeny. We may become ever more efficient sanding, trimming, and wedging people into niches that -- without the gifts of genetics and medications -- would never be tolerated.