Some Common Misconceptions
Dr Paul St John Smith reflects on his personal journey and unpacks some of the most common misconceptions surrounding evolution-based thinking in psychiatry.
We’ve had the pleasure of featuring Paul in different ways on this Substack over the past couple of years, so we were especially thrilled when he agreed to write a full-length feature for us—this time diving into some of the most persistent misconceptions about evolutionary psychiatry:
I first became interested in evolution in the 1970s while studying for A-Level biology. However, on entering medical school, even doing a Natural sciences degree at Oxford, in various biological sciences, the possible insights from evolution were generally actively ignored. Despite questioning in subjects like embryology where phylogeny seemed to me to partly explain ontology or in subjects like immunology, where homologous selection processes in a non-germ line, explains how mutations allow for new cell lines and antibody diversity, Darwinian ideas seemed to be assiduously ignored. In anatomy there were no evolutionary explanations for strange anomalies like the recurrent laryngeal nerve and why it goes around the heart etc etc. Some even said they did not believe in evolution!
Furthermore, when directly asking about evolution some lecturers and teachers seemed genuinely perplexed, anti-Darwinian or just said words to the effect “yes it evolved” and clearly had thought no more deeply about it. Some even said they did not believe in evolution!
I had to let it rest!
Whilst working as a junior doctor, life was too busy to think abut such matters, but when I became a consultant psychiatrist in 1994, I realised, I was not completely satisfied with current psychiatric models and concepts. There seemed a lot of differing ideas and models including even anti-psychiatry! These were often competing and even mutually exclusive. I knew there were some evolutionary ideas out there about psychiatry, from Crow and Mayr and a few others, but nothing systematic regarding the whole field. I wondered if any further Darwinian ideas had been considered and whether they might illuminate these issues. I found and read Williams and Nesse’s book “Why we get sick” subtitled “The birth of Darwinian medicine”. The chapter “Are psychiatric disorders diseases?” suddenly made more sense than any other general article about psychiatric models had done hitherto. I then looked up everything I could on relevant evolutionary psychiatry and psychology, one benefit of the new internet. I stared adding in evolutionary ideas to the papers and articles I was writing, on such subjects as placebo effects, pharmacology and substance misuse.
Whilst organising a conference at the RSM I persuaded. my friend, colleague and intellectual sparring partner Professor George Ikkos, to invite Randolph Nesse over to the RSM. There I not only met Randy for the first time but also, by sheer luck, was sitting near Riadh Abed and his colleague Mohammed Abbas whose names I thought I recognised from some evolutionary papers they had written. I introduced myself and indeed Riadh was the author of those evolutionary papers. We got along, kept in contact and began a creative dialogue. Eventually Riadh suggested we try to set up a special interest group at the RCPsych. The rest is history but the story of EPSIG can wait till another time.
Nevertheless, despite going for nearly 10 years and over 3000 members in EPSIG we have only just begun to get evolution considered and still find inertia, denial, scepticism and just plain disinterest in many places. Arguably it is mainly the trainees, who are an inspiration, that seem to be realising the value of evolutionary ideas. Co-operation with our colleagues in Ireland has also been immensely rewarding. Nevertheless, there remains, in much of mainstream psychiatry, something between almost total unfamiliarity or plain disinterest in these ideas. Where there is genuine consideration there are also many misconceptions about evolution in psychiatry which I will detail below in an effort to put things straight.
“Nevertheless, despite going for nearly 10 years and over 3000 members in EPSIG we have only just begun to get evolution considered and still find inertia, denial, scepticism and just plain disinterest in many places. Arguably it is mainly the trainees, who are an inspiration, that seem to be realising the value of evolutionary ideas. ”
In summary, Evolutionary Psychiatry (EP) brings profound Darwinian “why” questions to complement psychiatry’s traditional biopsychosocial focus on “how” psychiatric disorders arise. It re-examines psychiatric epidemiology, genetics, biochemistry, and psychology through the lens of evolutionary science—drawing insights from comparative animal evolution, ethology, paleoanthropology, culture, philosophy, and the humanities. EP explores what it means to be human by investigating the functions—or “purposes”—of the mind and brain. It seeks evolutionary explanations for persistent, heritable traits such as syndromes, defences, emotions, cognition, and behaviours, shaped by natural, sexual, and social selection, along with other evolutionary forces.
EP considers human traits—both unique to our species and shared—alongside behaviours and disorders, using evolutionary history (phylogeny), individual development (ontogeny), and perspectives from psychotherapy and the social sciences. It examines how our evolved minds interact with modern environments, offering fresh insight into causation, prevention, and treatment—medically, socially, and humanistically.
Ultimately, EP aims to enrich rather than replace existing psychiatric knowledge. However, it does challenge certain prevailing medical perspectives by asking why particular genes—especially those that increase vulnerability to psychiatric disorders—persist in the population. In doing so, it flips the conventional approach: instead of starting with how genes cause illness, it asks why these genes exist in the first place and how they might have been adaptive in ancestral contexts.
Some Common Misconceptions about Evolution and Psychiatry
Unfortunately, there remains a number of misconceptions about evolution and psychiatry (EP). Whereas we cannot cover all the public’s misconceptions about psychiatry itself in a brief article, we can mention some of the problems at the intersection. Evolutionary psychiatry applies the principles of evolutionary biology to understand the origins and persistence of mental health disorders.
Here are some common misconceptions about the intersection of evolution and psychiatry:
Evolutionary Psychiatry is a branch of psychiatry in opposition to conventional models
This is wrong from the “get-go” as EP is partly a perspective and accepts the mainstream scientific thought and clinical practice. It illuminates research and practice and does not seek to replace mainstream psychiatry, instead complimenting existing frameworks. It is not an ideology or a separate method of clinical practice.
Evolutionary psychiatry ignores environmental factors
One misconception is that EP attributes all mental health disorders solely to evolutionary history, neglecting the influence of environmental factors such as trauma, development, socioeconomic status, and cultural norms. In reality, evolutionary psychiatry acknowledges the complex interplay between evolutionary factors and environmental influences in shaping mental health.
Evolutionary explanations are deterministic
Some may mistakenly believe that EP proposes simplistic or overly reductionist deterministic explanations for mental health disorders, implying that individuals are predetermined to develop certain conditions due to their evolutionary history. However, EP emphasizes that genetic predispositions interact with environmental factors often in a myriad of unpredictable ways, leading to a range of possible outcomes for mental health.
Evolutionary psychiatry pathologizes natural behaviours
There's a misconception that EP automatically pathologizes behaviours that were adaptive in ancestral environments but may be maladaptive in modern society (Mismatch). For example, traits like anxiety, substance use, or aggression may have had adaptive value in certain contexts but can contribute to mental health disorders in contemporary settings. However, EP aims to understand the evolutionary origins of behaviours without necessarily pathologizing them, recognizing that they may vary in their adaptiveness depending on the context.
We also try to avoid simplistically asserting automatically that psychiatric disorders are adaptations or that adaptations are disorders. These errors of attribution and thinking are common and are a hinderance to the field being taken seriously. For instance, moods have adaptive value, but severe mania or psychotic depression are not adaptive. Likewise thinking is adaptive but thought disorder is not. The real issues in evolution and psychiatry and what constitutes illness, disease and disorder are much more complex and deserve more nuanced conceptualisation. The examination of these complex issues is part of our aims.
Evolutionary psychiatry is reductionist
Another misconception is that EP oversimplifies mental health disorders by reducing them to evolutionary explanations, neglecting the complexity of psychological, social, and biological factors involved. In reality, evolutionary psychiatry seeks to integrate evolutionary insights with other perspectives, such as neuroscience, psychology, anthropology, epidemiology, genetics, and sociology, to provide a comprehensive understanding of mental health. In reality, mainstream biological psychiatry with its focus on molecular and neurotransmitter events is excessively reductionistic and EP with its broader concept of the biological can help overcome this reductionism.
Evolutionary psychiatry suggests that mental health disorders are universal
While EP emphasizes the universality of certain evolved psychological mechanisms, such as fear or social bonding, it does not imply that mental health disorders are universally expressed or experienced in the same way across all cultures. Cultural and contextual factors play a significant role in shaping the manifestation and interpretation of mental health disorders, and EP takes these factors into account in its analyses.
By addressing these misconceptions, EP can contribute valuable insights to our understanding of mental health disorders, emphasizing the importance of considering both evolutionary and environmental influences in shaping human psychology and behaviour.
In more general evolutionary terms, Darwinian evolution, despite its widespread acceptance in the scientific community, is often misunderstood or misrepresented in popular discourse. Here are some common general misconceptions:
Evolution is just a theory
In scientific terms, a theory is a well-substantiated explanation of some aspect of the natural world that is based on a body of evidence. Evolution, including Darwinian evolution, is supported by an overwhelming amount of evidence from multiple fields such as palaeontology, genetics, comparative anatomy, and molecular biology. It's not just a guess or a hypothesis.
Evolution is entirely random
While mutation, one of the driving forces of evolution, is mainly random, natural selection is not. Natural selection acts on the variation generated by mutation, favouring traits that enhance an organism's survival and reproduction in a given environment. Evolution is the result of the non-random process of natural selection acting on random genetic variation.
Evolution is linear:
Evolution does not always proceed in a linear fashion from simple to complex. It's a branching process, with species diversifying and adapting to various ecological niches over time. The evolutionary tree of life resembles a complex web of interconnected branches rather than a straight line.
Individuals evolve
Evolution occurs at the population level, not the individual level. While individuals within a population may possess certain traits that provide advantages in survival and reproduction, it's the frequency of these traits in the population that changes over time due to natural selection, genetic drift, gene flow, and mutation. Individuals may adapt or develop but the ability to do that may be what has evolved and may be what has been selected.
Evolution is not progressive
Evolution does not have a predetermined goal or endpoint. It's not about becoming "better" or more advanced; it's about adaptation to changing environments. Organisms evolve traits that increase their fitness within their specific ecological context, but these traits may not necessarily make them "better" in an absolute or permanent sense. Teleology, the idea that natural processes are directed toward specific goals or purposes, is considered inappropriate in the context of evolution for several reasons:
Lack of evidence for purpose or intent: Evolutionary processes, such as natural selection, operate without foresight or intentionality. Traits that increase an organism's fitness are favoured by natural selection because they confer reproductive advantages in specific environments, not because they are striving toward a predetermined goal. There is no evidence to suggest that evolution is guided by a teleological force or purpose. Evolution is characterized by variability and contingency rather than a predetermined direction or purpose. The outcomes of evolution are influenced by a myriad of factors, including genetic variation, environmental changes, chance events, and historical constraints. As a result, evolution does not follow a linear path toward a specific endpoint but instead leads to diverse and often unpredictable outcomes.
Evolution is not progressive: Teleological thinking often implies a notion of progress or advancement, with organisms evolving toward greater complexity or perfection. However, evolution does not necessarily lead to more complex or "better" organisms. Adaptations that enhance an organism's fitness are favoured by natural selection, but what constitutes "fitness" depends on the specific environmental conditions and ecological interactions. Evolutionary change does not inherently imply progress or improvement.
Incompatibility with scientific methodology: Teleological explanations rely on attributing purpose or intention to natural phenomena, which falls outside the realm of empirical science. Science seeks to explain natural phenomena based on observable evidence and testable hypotheses, without invoking supernatural or teleological explanations. Teleology lacks predictive power and explanatory value within the framework of scientific inquiry.
In summary, teleology is considered inappropriate in the context of evolution because it does not align with the evidence-based principles of evolutionary biology.
Evolutionary processes are driven by mechanisms such as natural and other forms of selection, genetic drift, and mutation, which operate without independent foresight or intentionality and lead to diverse and contingent outcomes shaped by environmental factors and chance events. Genetic engineering by humans may change this slightly but the organisms will still be subject to selection processes and unexpected outcomes will still arise.
Humans are not evolving. Or you cannot apply evolutionary ideas to humans.
Wrong! humans are still evolving. Evolution is an ongoing process, and all living species, including humans, continue to adapt to their changing environments through natural selection, genetic drift, gene flow, and mutation. In any environment, there will be differences in survival and reproductive success associated with different heritable traits. Also, unexpected changes in environmental conditions (epidemics, climate change, technological innovations etc.) can favour some individuals over others, leading to changes of gene frequencies over generations. While the pace of human evolution may be different in type to other organisms due to factors like cultural practices, technological advancements, and medical interventions, there is evidence to suggest that human populations are still undergoing genetic changes.
For example, studies have identified genetic adaptations in human populations in response to selective pressures such as disease resistance, diet, climate, and altitude. Additionally, factors such as migration, interbreeding between populations, and changes in lifestyle can influence the genetic makeup of human populations over time. A disease epidemic might selectively kill people with certain genes but not others, leading to a change in frequency of such genes. This could happen rapidly. That would be evolution in action. However, as medical doctors we try to oppose any such Natural Selection by trying to treat people or even prevent such events.
Recent advances in genetics and genomics have provided insights into ongoing evolutionary processes in humans. These studies have revealed genetic variations associated with traits like lactose tolerance, resistance to certain infectious diseases, and adaptations to high-altitude environments, among others. In summary, while the pace and nature of human evolution may differ from that of other species, humans are indeed still subject to evolutionary forces and continue to undergo genetic changes over time.
Evolutionary thinking can be and has been applied to human behaviour and thought, giving rise to fields such as evolutionary psychology and evolutionary anthropology. These disciplines seek to understand human behaviour and cognition through the lens of evolutionary theory, exploring how natural selection has shaped the psychological and social traits of humans over time. Overall, evolutionary thinking provides a valuable framework for understanding the complex interplay between biology, culture, and environment in shaping human behaviour and thought. While not without controversy and debate, evolutionary approaches have contributed significantly to our understanding of what it means to be human.
Understanding the detail and nature of these misconceptions can help foster a more accurate understanding of Darwinian evolution and its role in humans. Unfortunately, many people retain persistent misconceptions about evolution and especially with its intersection with psychiatry. Some are simple misunderstandings, ideas that develop in the course of learning about evolution, possibly from school experiences and/or the media. Other misconceptions may stem from purposeful attempts to misrepresent evolution and or psychiatry and undermine the public’s understanding of this topic or wilful ignorance because of some predetermined political, commercial, or ideological stance. At EPSIG we hope we can dispel some of these misconceptions for those with an open mind who wish to be more curious about evolution and its relation to mental health and human behaviour.
If you enjoyed this article and would like to discover more about Evolutionary Psychiatry please consider:
subscribing to our Substack to receive regular content updates
visiting the webpage of the Evolution and Psychiatry Special Interest Group within the College of Psychiatrists of Ireland
visiting the webpage of the Evolutionary Psychiatry Special Interest Group within the Royal College of Psychiatrists
exploring a Youtube playlist on curated presentations by the Evolution and Psychiatry Special Interest Group within the College of Psychiatrists of Ireland
exploring the Youtube page of the Evolutionary Psychiatry Special Interest Group within the Royal College of Psychiatrists
exploring the Evolving Psychiatry podcast
Thanks for this excellent piece! Like the other commenter, I'm a layperson interested in these topics. I hit on evolutionary mismatch theories and research as they pertain to neurodivergence here: https://strangeclarity.substack.com/p/evolutionary-mismatch-just-one-part
I'd love to see more on this topic from open-minded experts. What the author writes about -- hostility to new ideas -- I see often in the autism field, unfortunately.
This is fascinating and a subject area that I have been interested in for decades, although only as a layperson.
Do you know if there are any recorded studies for the village of Oberammagau in Europe which escaped the Bubonic Plague and so could provide a useful "before and after" for the way humans have evolved post pandemic from the middle ages?