In this two part video, I examine the hypothesis that ADHD is not a disorder but is simply a mismatch between modern culture and traits that were adaptive for some reason earlier in human evolution. This adaptationist or mis-match idea argues that cultural evolution proceeded far more quickly than biological evolution such that a trait or set of traits that were once adaptive or helpful to human survival in earlier periods of human evolution have become maladaptive due to changes in culture such that these traits are no longer adaptive. For example, Hartmann’s idea that ADHD represents earlier successful hunters during the hunter-gatherer phase of evolution now forced to live among farmers in contemporary culture. Or Jensen and colleagues’ idea that ADHD represents adaptive traits for warfare during an earlier human epoch that are new at odds with a relatively more peaceful contemporary culture.
Part I of this video examines these ideas as well as the evidence for the current known etiologies of ADHD to see how well they agree or disagree.
In Part II, I go on to explore an alternative, more scientifically based theory of ADHD as a set of maladaptive traits that can remain at a stable rate within a human population. This “conveyor belt” theory by Keller (2008) argues that new mutations arise all the time in the genes for ADHD (and other neurodevelopmental disorders) in each new generation and that it takes multiple generations for natural selection to remove those original mutations. Despite their being removed, new mutations continue to arise in the next generation that go on to create disorder. If the new mutation rate and the genetic removal (death) rates (natural selection) reach a certain level of balance with each other, the result is a stable rate of a maladaptive trait (disorder) within a population (say, 5-8%). The available evidence is more consistent with this theory than with the hypothesis of cultural mismatch.
Esteller-Culcala, P. et al. (2020). Genomic analysis of the natural history of attention-deficit/hyperactivity disorder using Neanderthal and ancient Homo Sapiens samples. Nature Research: Scientific Reports (10).
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Hartmann, T. (1993). Attention deficit disorder: A different perspective. Novato, CA: Underwood Miller Press.
Jensen, P. S. et al. (1997). Evolution and revolution in child psychiatry: ADHD as a disorder of adaptation. Journal of the American Academy of Child and Adolescent Psychiatry, 36, 1672-1679.
Keller, M. C. (2008). The evolutionary persistence of genes that increase mental disorders risk. Curren
