Evolutionary epidemiology and manic depression

The reformulation of epidemiological prevalence rates as evolutionary frequ ency rates puts medical genetics within an explicit framework of Darwinian theory. Yet an enduring and still current assumption of genomic medicine is that genes associated with disease are necessarily maladapted. Indeed, it seems it could hardly be otherwise. However, evolutionary epidemiology has begun to uncover important and surprising counter-exemplary case-studies. T hus, the present aim is to first outline this emerging sub-discipline of 'e volutionary epidemiology'. Then, a major psychopathological syndrome-manic- depression-is examined in some detail within the purview of evolutionary ep idemiology. Its medical generics are those of an adaptive polymorphism in t he human genome. Hence, genes associated with what is now a major public he alth problem accrued as they conferred selective advantage in phylogeny. Wh y should manic-depressive etiogenes have been selected! A preliminary anato mic-functional model, assembled from facts of human paleoneuropsychiatry, m ore adequately contextualises manic-depressive genomics and phenotypy. In t his model, manic-depression finds its heuristic origins in a hierarchy of b ehavioural strategies stabilised in phylogeny and embedded at serial levels in the brain (Hawk-Dove ESS). A proportion of the population has variant g enotypy which appears to have been favoured in social competition phylogene tically but express more pathogenic phenotypy in the current environment. T he paper closes with a brief consideration of clinical practices and ethica l issues as alternative considerations emerge with the syndrome recast in a more positive Darwinian light.