This year's ISEMPH conference was fully online, and I organised a symposium on the subject of 'Evolutionary Psychiatry and Neurodiversity'. The recordings will eventually be available to watch online on the ISEMPH YouTube channel, and I will also list the speakers and their abstracts in this post. I believe this was somewhat of a landmark event - I am not aware of any prior session considering the relationship between evolutionary psychiatry and neurodiversity in such an extended academic context.
I was very happy with how the presentations fitted together, giving a rounded view of the areas of empirical and theoretical importance, although the main take away from the symposium may be that this is still early stages (indeed, both evolutionary psychiatry and neurodiversity are fledgling topics, so this is to be expected). The various points of convergence and divergence between the social movement of neurodiversity and the scientific approach of evolutionary psychiatry are worth considering and came up in the speakers discussion. We are planning a joint paper together discussing these issues.
Here are the abstracts - when recording links are available, I'll post them here too:
Highly heritable, common, lifelong mental disorders such as ADHD, autism and dyslexia exist on spectrums blending with apparently normal variation. Why do they persist despite natural selection? A growing ‘neurodiversity’ movement claims these are differences rather than diseases, natural human cognitive variation with unrecognised strengths, inappropriately pathologized – evolutionary mismatch explanations have similar connotations. So, are certain common mental disorders evolved but mismatched individual differences? What evolutionary forces maintain their spectrums? Is modern reproductive success representative? What are the practical and ethical connotations of this research? This symposium shall consider the major goals and challenges of relating neurodiversity to evolutionary psychiatry.
Adam Hunt URL: www.adamhunt.info Evolutionary psychiatry meets neurodiversity
‘Neurodiversity’ is the term used by a growing social movement seeking to reconstrue certain common mental disorders as natural cognitive variation. This movement has been driven by diagnosed individuals on socio-political, rather than scientific, grounds. This introductory presentation relates the big questions motivating this symposium: Could evolutionary theory explain neurodiversity? What relevant empirical research exists, and what is required? How would evolutionary theories align with the neurodiversity movement? How would they conflict with it? What are the broader implications for society? Evolutionary mismatch explanations in particular share many similarities with the neurodiversity perspective: both claim natural differences, rather than true disease or dysfunction; both frame conditions in terms of strength and weakness profiles rather than simple disability; both propose modern environments disproportionately disadvantage certain individuals; and both carry implications that social accommodation and integration should be sought, rather than simple cures. Yet there are differences to be hashed out between the evolutionary and neurodiversity approaches; for example, evolutionary explanations will necessarily exclude certain cases where dysfunction is clearly present, whilst the socially-motivated neurodiversity perspective can be boundlessly inclusive. Nevertheless, beginning serious work on this area is highly important – evolutionary approaches could provide superior scientific explanations in a socially desirable way.
No Key Paper
Marco del Giudice URL: https://psych.unm.edu/people/faculty/profile/marco-del-giudice.html Making sense of heterogeneity in autism and ADHD: A functional approach
A major obstacle to the evolutionary analysis of mental disorders is that many standard diagnostic categories are highly heterogeneous, and hence are going to require multiple and often divergent explanations. In turn, different explanations are likely to have different implications for the connections between evolution and “neurodiversity”. In this talk, I discuss how evolutionary psychopathology offers a richer taxonomy of explanations than other approaches—one that is not limited to classic categories of dysfunction, adaptation, and mismatch. I then consider the nature of autism spectrum disorders (ASD) and ADHD from the standpoint of the FSD (fast-slow-defense) model of the structure of psychopathology. I argue that ASD comprises at least two functionally distinct but partially overlapping subtypes, whereas ADHD comprises at least three, and present a selection of recent evidence that supports this classification.
No key paper; see ‘Evolutionary Psychopathology’ (2018) book
Tanya Procyshyn URL: https://www.autismresearchcentre.com/staff/tanya-procyshyn/ Do autism genes collectively shape the human brain and behaviour?
Autism refers to highly heterogenous, highly heritable conditions commonly associated with social challenges but perceptual strengths. Research aimed to identify the genetics of autism has revealed that the majority of autism risk is conferred by common variants, i.e. genes present in the general population that individually make small contributions to autism likelihood. Using the results of genome-wide association studies for autism, it is possible to compute a score representing the cumulative number of autism-related genetic variants that a person carries. To date, such polygenic scores for autism have been found to relate to emotional intelligence, self-harm/suicide behaviour, and executive functioning in the general population. The recent availability of datasets with both genetic and neuroimaging data for tens of thousands of people has now made it possible to explore relationships between polygenic autism scores and brain structure and function. This approach can be used to explore the possibility that the same genes that confer liability to autism shape brain and behaviour in the general population, with relevance to both evolutionary and neurodiversity accounts of autism.
Key Paper: https://www.nature.com/articles/s41380-019-0550-x (although only tangentially related)
Psychiatry has a long history of (mis)classifying socially undesirable behaviors as ‘diseases’, and leading figures in the field warn that psychiatric diagnosis continues to pathologize normal and healthy variation, a central claim of the neurodiversity movement. According to Wakefield’s ‘harmful dysfunction’ concept of disease, ‘harmful’ signifies a subjective value judgement, and ‘dysfunction’ is the failure of a trait to perform its evolved function. Inspired by this concept, Syme and Hagen (2020) developed a provisional evolutionary schema of mental disorders that groups conditions based on population prevalence, heritability, and age of onset, producing 4 categories: genetic/developmental disorders, senescence, adaptive threat responses, and mismatch. However, the provisional schema in its present form, based on data from western populations, does not address how to differentiate distinct types of mismatch. Evolutionary mismatch might cause social harm, dysfunction, or both. Focusing on autism spectrum disorders and attention deficit hyperactivity disorder, I will discuss how anthropological and health data across societies that vary in ecology, political complexity, and social values can help diagnosticians distinguish social harms from harmful dysfunctions.
Key Paper: https://doi.org/10.1002/ajpa.23965
Robert Chapman URL: https://research-information.bris.ac.uk/en/persons/robert-chapman Neurodiversity and cognitive functioning: towards an ecological framework
Abstract: The conceptual question of what it means for a mind to have ‘malfunctioned’ underlies the practical issue of counts as a mental disorder. In evolutionary psychiatry, functional analysis seeks to be consistent with evolutionary biology. As such, proper function is determined by selection history or fitness propensity, and dysfunction is understood as cognitive mechanism failure or evolutionary mismatch. The neurodiversity movement provides a challenge to this way of conceptualising functioning. Neurodiversity proponents build their analysis on ecology rather than evolutionary biology. On this view, neuro-cognitive diversity is vital at the group level, and variation is part of what constitutes functioning. Here I explore how this leads to a different way of conceptualising mental health, and how it grounds the kinds of claims made by neurodiversity proponents.
Key Paper: https://doi.org/10.1177/1745691620959833