One of the eight principles that I discuss in my book Neurodiversity is that everyone exists along “continuums of competence” with respect to a range of human processes including sociability, literacy, intelligence(s), attention, mood, and so forth. This is very similar to the DSM-V’s embracing of a dimensional perspective, and to that extent, I think the DSM-V is moving in the right direction. The problem is that the DSM-V will be a high stakes publication, and if people are put on a continuum from normal to pathological, the fuzzy line where normal becomes pathological (and vice versa) becomes very important, and may determine whether a person will be labeled with a disorder, given a drug treatment, and perhaps even stigmatized as a result. There’s a danger that many so-called normal people will be added to the ranks of the mentally disordered. Also, what’s missing from the DSM (in all its versions) is any kind of discussion of the positive dimensions of each of the disability categories.Genomic studies continue to struggle to find correlations between specific polymorphisms and psychological traits (see here). What this indicates is that a bunch of little genetic polymorphisms shift your tendencies in one direction or another, but there are no large discrete steps.
So, statistically speaking, we should all be somewhere on the spectrum of every sort of tendency and disorder. Now, people surely shift along these spectrums, due to changes in one's environment, developmental clocks, and the probabilistic nature of gene expression. But people should still remain somewhere on the spectrum of any given cognitive style.
I will spare you my rampant speculation from this point on, but believe me, I could go on for days. The bipolar spectrum, the schizophrenia spectrum, the addiction spectrum, to name a few: it is very interesting to extrapolate from the idea that we all should be at least somewhere along these.