This post discusses cliff-edged fitness functions by Randolph Nesse (psychiatrist and one of the founders of evolutionary medicine) and the 2024 paper, “The cliff edge model of the evolution of schizophrenia: Mathematical, epidemiological, and genetic evidence,” by Philipp Mitteroecker and Giuseppe Pierpaolo Merola.If you are a regular reader of this newsletter, and it deepens your intellectual life, consider a paid subscription to support this effort.The persistence of schizophrenia is an evolu...