Evolutionary Psychiatry
By Adam D. Hunt
Our evolutionary history is often ignored when thinking about mental health. We forget that the world humans lived in for millions of years – which our brains and minds are designed for – was very different to today. We assume a mental health diagnosis means ‘something has gone wrong’ in the person. But what if that person’s difficulties are more related to changes in the world, and modern expectations for how minds should work? We expect people to sit still in classrooms, read with ease… but classrooms and writing are very new inventions. Nobody ‘should’ be able to sit still in classrooms or read with ease, evolutionarily speaking. The fact that some can and some can’t is a matter of happenstance, but doesn’t reflect true biological breakage. It may be better understood at what is called ‘evolutionary mismatch’ - our bodies and brains aren't designed for this world, and sometimes we medicalise the problems which result.
Evolutionary psychiatry is a scientific discipline reframing mental health conditions by trying to explain them in relation to our evolutionary history. When it comes to neurodiversity, there are big questions which previous biomedical approaches haven’t managed to solve – why are these cognitive differences so common in the population, last so long, and appear so early in life? They are somewhat genetically caused, and the genes which make people autistic, or ADHD, or dyslexic, are clearly common in the population, and affect us for all our lives. This isn’t what we expect from disease, which often appears later in life, or is rare, or not inherited. Evolution could have caused everyone to be neurotypical, if that is what is optimal. But it hasn’t. Why?
One of the key evolutionary explanations for explaining neurodiversity is actually the same process which should explain ‘normal’ personality traits – we differ in extraversion, and we differ in autistic traits, and the same evolutionary dynamics should explain why those differences persist. There is a reason why we aren't all extremely extraverted or extremely introverted, or all extremely autistic or non-autistic - there is a reason our minds work differently from one another. The core dynamic revolves around cognitive strengths and weaknesses, and how they fit into our social groups. Our ancestors lived in close bands and tribes, hunting and gathering food every day as a collective. Within social groups, individual differences can evolve, as a sort of division-of-labour, or what is termed ‘social niche specialisation’ in evolutionary biology. Within our hunter-gatherer ancestral groups, for millions of years, assuming similar rates of autism, ADHD, dyslexia, and all sorts of neurodivergent traits, there would always be at least one autistic person per extended tribe (of about 150 individuals) and one person with broad autistic traits (the ‘broad autism phenotype’), one person with ADHD and one with dyslexia per band of individuals who sleep and hunt together on a daily basis (of about 25 individuals). The same goes for most neurodivergent traits. Although we can’t know for sure how they fitted into those societies, all of the genetic and biological evidence implies that those individuals were there, and weren’t any worse off in evolutionary terms than neurotypical people. The basic inference should be that their strengths were balanced with their weaknesses, and that they found a way to fit in in those societies.
It’s widely recognized, both by science and people familiar with neurodivergent people on a personal basis, that despite experiencing problems which others don’t due to their cognitive style, they also show strengths that others don’t. In the realm of sport this could manifest as unusual obsessiveness, attention to detail, and dedication. The same tendencies can lead to exemplary ability in all sorts of other realms of life, too. And they come with costs. But those costs, at least evolutionarily speaking, were probably justified by the benefits – that’s why these traits persist in the human population in so many people, that’s why we have never found biomedical evidence of ‘pathology’ causing them, and that’s why if we were to shift our expectations and our environments to better incorporate neurodivergent people, supporting them through their weaknesses and harnessing their strengths, we would actually be tapping into an evolutionarily-ancient well of human potential, overlooked for too long by contemporary mainstream psychiatry.
Link to Adam's article Specialised minds: extending adaptive explanations of personality to the evolution of psychopathology.
Link to Adam's podcast Evolving Psychiatry.