Evolutionary psychiatry and the schizophrenia paradox: a critique

Abstract

Abstract. Evolutionary psychiatrists invariably consider schizophrenia to be a paradox: how come natural selection has not yet eliminated the infamous 'genes for schizophrenia' if the disorder simply crushes the reproductive success of its carriers, if it has been around for thousands of years already, and if it has a uniform prevalence throughout the world? Usually, the answer is that the schizophrenic genotype is subject to some kind of balancing selection: the benefits it confers would then outbalance the obvious damage it does. In this paper, however, I will show that the assumptions underlying such evolutionary accounts of schizophrenia are at least implausible, and sometimes even erroneous. First of all, I will examine some factual assumptions, in particular about schizophrenia's impact on reproductive success, its genetics, its history, and its epidemiology. Secondly, I will take a critical look at a major philosophical assumption in evolutionary psychiatric explanations of schizophrenia. Indeed, evolutionary psychiatrists take it for granted that schizophrenia is a natural kind, i.e. a bounded and objectively real entity with discrete biological causes. My refutation of this natural kind view suggests that schizophrenia is in fact a reified umbrella concept, covering a heterogeneous group of disorders. Therefore, schizophrenia, as we now know it, simply doesn't have an evolutionary history.

A community survey of psychological symptoms: evaluating evolutionary theories regarding shamanism and schizophrenia

“…Various theories explain this situation. Schizophrenia may be merely an umbrella concept, covering a heterogeneous group of disorders (Adriaens, 2007). If no distinct disorder exists, it will be impossible to specify phenotypes precisely.…”

Concepts of mental disorders in the United Kingdom: Similarities and differences between the lay public and psychiatrists

“…Over the past 20 years, there have been significant efforts within the scientific community to link our biology-specific alleles to specific mental disorder without great progress (Keller, 2008). Indeed, there is increasing recognition of the phenotypic and genotypic variation within specific disorder (Adriaens, 2007). The allure of biological psychiatry, the belief that mental disorders are distinct categorical entities, with fixed internal properties has been greatly discussed and critiqued (e.g.…”

Folles histoires: de l’utilité et des inconvénients de la psychiatrie évolutionniste

“…Mais encore faut-il savoir de combien de gènes il s'agit, et quel est l'effet de chacun d'eux ? Les psychiatres évolutionnistes se préoccupent rarement de la complexité génétique de la schizophrénie [1]. Ils se laissent trop souvent séduire par la rhétorique des généticiens psychiatriques, qui prétendent depuis plus d'un quart de siècle déjà qu'ils sont sur la trace des gènes de la maladie, avant d'ensuite disparaître discrètement de la scène.…”