A Leading Light in Evolutionary Psychiatry - Dr Riadh Abed, FRCPsych
Edited by Dr Gurjot Brar & Prof Henry O'Connell
It was absolutely incredible talking with Riadh who has been a leading light and eminent scholar in Evolutionary Psychiatry. In addition to publishing for nearly three decades in the field, Riadh has been instrumental in the founding of the first Evolutionary Psychiatry Special Interest Group in the world with the Royal College of Psychiatrists, and editor for the landmark Evolutionary Psychiatry text published by Cambridge University Press. We hope you enjoy this interview as much as we enjoyed producing it.
Foreword by Prof Henry O’Connell
Dr Riadh Abed is the Founding Chair and current Financial Officer of the Royal College of Psychiatrists Evolutionary Psychiatry Special Interest Group (EPSIG), the first national organisation of its kind. Riadh is also Chair of the World Psychiatric Association Faculty of Evolutionary Psychiatry. He has published widely on all aspects of evolutionary psychiatry and made very significant original contributions in the areas of eating disorders, OCD and psychosis. With Paul St John-Smith he published the multi-authored text ‘Evolutionary Psychiatry: Current Perspectives on Evolution and Mental Health’ in 2022 and this is now the definitive volume on evolutionary psychiatry. At a personal level, Riadh is a warm, enthusiastic and endlessly encouraging and helpful colleague and friend and he has been of immense help to us in establishing our own Special Interest Group in Ireland.
Please introduce yourself for those who don’t know you!
I’m a retired NHS adult psychiatrist, currently a medical member of the Mental Health Tribunals in England. I’m a graduate of Baghdad Medical School in 1974, did my residency, compulsory military and rural services in Iraq and subsequently started my psychiatric training there. I came to the UK in 1979 where I completed my psychiatric training in London, Maidstone, Liverpool, Norwich and Cambridge before taking up a consultant post in 1987 in Rotherham, South Yorkshire where I later became medical director of a trust that covered Rotherham, Doncaster and Scunthorpe in the last 7 years of my NHS career. I was also Honorary Senior Clinical Lecturer at the University of Sheffield. I retired from full-time NHS work in 2012. I am founding chair of EPSIG-RCPsych (UK) and current chair of the Section of Evolutionary Psychiatry at the WPA.
How were you introduced to the field of evolutionary psychiatry and what interested you in it?
I came to evolutionary psychiatry via evolutionary psychology and evolutionary anthropology rather than evolutionary medicine.
I ran a psychosexual clinic in Rotherham for around 10 years from the late 1980s onwards. During that time, I came across a book by Donald Symons, an American evolutionary psychologist, titled ‘The Evolution of Human Sexuality’ which discussed human sexuality within an evolutionary framework. This book was a massive eye-opener for me, and I can say, led to a major turning point in my intellectual life. At a stroke, it changed my view of psychology and human behaviour and, of course, of psychiatry and mental disorders. For the first time I realised that human psychology and human behaviour could be better understood and start to make much more sense when viewed through an evolutionary lens. It was exhilarating to me to be able to organise masses of disparate data regarding both functional and dysfunctional states in a meaningful way rather than having to learn lists of dry and seemingly unconnected facts (which characterised much of medical education in my day).
Shortly afterwards, I discovered the then nascent evolutionary psychology literature including the newly published ‘Adapted Mind’ (1992) (still a book well worth reading as it contains some real evolutionary gems). I couldn’t get enough of that literature and was reading anything I could get hold of. Unlike today, the evolutionary psychology literature was not as plentiful as it is currently so I turned to evolutionary anthropology and read everything I could lay my hands on (all in paper form, of course, as the internet was still in its infancy and the Google search engine hadn’t yet been invented). I did all my reading and subsequent evolutionary writing throughout the 90s with no evolutionary peer group which was very frustrating. My efforts in trying to interest colleagues across South Yorkshire and further afield, in the value of evolution to the understanding of psychology and psychiatry, came to very little. Although I was invited to present evolutionary talks at various local and regional CPD events and colleagues listened to me politely, evolution didn’t seem to produce a lasting impression on my audience.
In the late 90s I started publishing evolutionary articles, mostly solo, but at times with others. This included novel evolutionary hypotheses on psychiatric conditions such as eating disorders (1998), OCD (1999) and subsequently schizophrenia (2011). Also, in 2000 I published an editorial in the BJPsych advocating for the incorporation of evolutionary thinking into psychiatry and this, to my knowledge, was the first time the BJPsych had published such an article. Interestingly, the editorial sparked a vigorous debate (both for and against) in the correspondence section of the journal, which was unprecedented in its extent and persistence and continued for some 8 months.
Throughout my NHS career I was either a full-time clinician or part clinician, part medical manager with only an honorary academic status without any formally allocated academic time. However, I continued to devote some of my spare time and energy to both theoretical and empirical evolutionary research which resulted in a number of publications.
You were instrumental in founding the special interest group with the Royal College of Psychiatrists.
What prompted you to found that group and how has that journey been since?
The founding of EPSIG involved a series of chance events. Having worked on evolutionary projects in relative isolation for a number of years with no peer group or other support, I happened to meet Paul St John-Smith at a Royal Society of Medicine conference in 2013. He also had been interested in evolution for some years and was similarly bereft of any evolutionary support network. From then onwards we kept in touch and in our discussions, we wondered how we could promote evolution within the RCPsych. By pure chance, I came across an announcement by the college that there was an opening for a proposal of a new Special Interest Group. The RCPsych charter has a peculiar rule that limits the number of SIGs to a maximum of 15. So, unless a SIG is disbanded, no new SIG can be formed. I was convinced that it would be futile to propose an evolutionary psychiatry SIG and this pessimism was shared by Paul and all colleagues and friends whom I consulted. Nevertheless, I thought that there would be nothing to lose by going through the process with the college especially that such an opportunity may never come up again during my lifetime. The internal college process of proposing a SIG is quite elaborate and lengthy and importantly, requires the support of 120 members/fellows of the college. This looked like an insurmountable obstacle as it seemed certain that there wouldn’t be such a number of psychiatrists in the UK who would both welcome the setting up of an evolutionary SIG and be motivated to vote for its formation. But to our utter astonishment and delight, the proposal achieved an amazing 180 votes in favour!
The whole process of setting up the EPSIG took over 12 months and the SIG was formally inaugurated in January 2016. Since then, EPSIG’s membership has continued to rise and is now over 3000 members which makes it the largest EP grouping anywhere in the world. Over the intervening 8 years we have published 34 newsletters, held 5 successful full day symposia (the 6th is due on 22 November 2024) and a similar number of half day scientific meetings. We have also formed a trainee group and held 2 successful trainee engagement workshops and set up our own YouTube channel with over 50 full lectures (together with Q&A) which has attracted around half a million hits so far. In addition, we have forged links with the University of Cambridge, the Section of Evolutionary Psychiatry at the WPA, the Irish EPSIG (the College of Psychiatrists of Ireland), the Royal Society of Medicine (with whom we are planning a joint conference in 2025) and the Philosophy Special Interest Group at the RCPsych (with whom we held a joint half day meeting in April 2024). As a result of the existence of EPSIG we have published editorials in both the BJPsych Bulletin (2016) and the BJPsych (2019) (with another BJPsych editorial accepted and due soon) and the RCPsych/Cambridge University Press edited volume; all of which may be considered spin-offs arising from the existence of EPSIG and are unlikely to have been conceived or seen the light of day without it.
Talk to me about the intriguing evobiopsychosocial model that you have developed with Adam Hunt and Paul St John Smith.
How does it seek to enhance the current paradigm/model in psychiatry?
What practical insights does evolutionary psychiatry have to offer to improve on the current paradigm/mainstream psychiatry?
The trigger for proposing the EvoBioPsychoSocial model (EBPSM) was the publication of a book on the BioPsychoSocial model (BPSM) by Bolton and Gillett in 2019. This is an excellent book that attempted to update and revitalise the concept in opposition to the dominant biomedical model. However, what we noticed was the glaring absence of any consideration of the place of evolution in our concept of health and disease. This prompted us to raise the question: Can the BPSM really be revitalised without evolutionary thinking? Specifically, we thought that it would not be possible to understand the true nature of the different levels of organisation (the bio, psycho and social) without reference to evolution. It is only when taking an evolutionary perspective that we come to recognise that it is possible to move away from a dualistic position. Evolution helps us appreciate that the ‘psycho’ and the social are emergent levels of organisation that have arisen and been shaped by selection in exactly the same way as physical structures of our bodies. In that sense, the ‘psycho’ and the social levels can be considered equally biological and as phenotypic end-products of evolution. Hence, we proposed a re-labelling of the ‘biological’ level as ‘somatic’ in recognition of the evolutionary-biological roots of all the levels of the BPSM.
The way we proceeded in our reformulation of George Engel’s BPSM was to combine his 3 levels with Nikolaas Tinbergen’s 4 causal domains so that each of the levels can be subjected to each of Tinbergen’s 4 questions. This results in a table with 12 cells, each of which explores an aspect of function and dysfunction. We propose that this can uncover aspects of human health and disease that may otherwise lie dormant and unexplored. The EBPSM is a work in progress and will require further theoretical clarification as well as empirical testing. However, we suggest that it holds the promise of advancing both our knowledge of health and disease as well as influence clinical practice. We have published a chapter and a journal article on this model, and we are delighted that there is also an editorial in the BJPsych on the model that is due to be published shortly.
Your edited textbook “Evolutionary Psychiatry – Current Perspectives on Evolution and Mental Health” has been a landmark publication in the field.
Can you take us through a little bit of the process of how it came to be and what it involves?
As already mentioned, the edited volume is a spin-off from the existence of EPSIG. Without it, such a book could not have been produced. The existence of EPSIG and especially through its academic activities (conferences, YouTube channel, published articles etc) had led to the creation of a network of evolutionary-minded scholars from a range of disciplines across the globe.
The idea of editing a book on evolutionary psychiatry arose when I came across a book published jointly by the RCPsych and CUP on Sports Psychiatry (which is another SIG at the college). I thought that if the Sport Psychiatry SIG can do it EPSIG should also be able to pull this off. Paul, my co-editor, was on board with the idea and we consulted with Derek Tracy, a member of the EPSIG executive committee and also an associate editor of the BJPsych. He was very encouraging and put us in touch with a contact at CUP. The application process for proposing an edited volume was very elaborate and required positive feedback from 5 reviewers and separate approval by each of the publishing boards of the RCPsych as well as CUP. Amazingly, the vast majority of the potential authors we approached accepted our invitation to participate in the volume and the range and stature of our authors had an obvious impact on the viability and eventual success of our proposal. The application and evaluation process took around 6 months to complete and another 18 months for the authors to complete their chapters, the editing and approval of the chapters and the final printing and publication of the volume (September, 2022). Unbeknownst to us at the time, this, in fact, was break-neck speed compared to many similar projects.
We were thrilled with the end-product which received positive, even glowing, endorsements from eminent scholars in the field and contained contributions from leaders in the field of evolution internationally who came from a range of academic disciplines. We think that the volume represents an important addition to the current EP literature and hope that it would remain an important evolutionary resource for anyone in the field of mental health or academia.
There are three main topics within Evolutionary Psychiatry where you have published.
These are OCD, psychosis (out-group intolerance) and eating disorders (sexual competition hypothesis).
Please could you describe how each of these came about and the evolution of these hypotheses/models?
I published and thought about the evolutionary models of these 3 disorders over an extended period of a quarter of a century or so (1998-2024). My first evolutionary work was on eating disorders (ED) (specifically anorexia and bulimia nervosa (AN & BN)). I had always been dissatisfied with the theories on EDs in the mainstream literature. The number and range of theories on EDs are legion but none of them has much explanatory value or power. Astonishingly, none of them are able to explain the basic and salient features of these disorders namely: Why do they primarily affect females? Why have whey arisen/increased in recent times? Why are they most prevalent in western and westernised societies?
I will not provide a critique for individual mainstream or evolutionary theories of EDs here (see a list and some full texts of my published articles/chapters, available on my ResearchGate page). The idea that intra-sexual competition had something to do with EDs came to me from the description of a very bright and insightful gay male bulimic patient. He described how his concerns about his physical attractiveness was related to his bulimic symptoms so that his confidence about being attractive to other gay men fluctuated in tandem with his bulimic symptoms. The bulimic symptoms of this particular patient were aimed at restoring a state of physical attractiveness, which, if achieved, the bulimic symptoms would abate. I then started to observe similar trends in female EDs (who are, of course, far more common). It occurred to me then that female intra-sexual competition (through the display of physical attractiveness) may be at the root of AN and BN and that certain features of western and westernised societies may have intensified competition which could lead to pathological EDs through mismatch in certain vulnerable girls and young women.
We know that the pursuit of thinness is widespread in western societies and is more marked in females. We also know that there is a large population of subclinical EDs who may engage in dieting and various forms of purging (occasionally) but never present to or need mental health services. This prompted us to conduct studies on non-clinical populations of women (university students) both in Arizona (USA) and Loughbrough (UK) where we used measures for competition for mates and status as well as other measures. In addition, the Loughbrough study included a life history strategy scale. The findings from these 2 studies have been published in 2005 and 2012 respectively and support the predictions of the Sexual Competition Hypothesis’ (SCH). A further small study of a clinical population of EDs (AN & BN) in Germany partially supported the SCH. Unfortunately, this study was underpowered. While both the BN group and the combined AN and BN showed significantly higher levels of competitiveness compared to controls, the AN group did not differ from controls. However, the higher scores on the Eating Disorder Inventory correlated with higher competitiveness for the combined AN and BN group. In addition, as per the predictions, the BN group showed evidence of faster life history strategy whereas the AN group did not differ from controls (i.e. had slower life history).
Interestingly, my attempts to persuade a UK-based ED specialist to collaborate on a study to test the SCH have so far failed. Also, to date, no ED association in the UK or internationally have taken the slightest interest in my hypothesis or showed any inclination to test it nor has any ED conference offered me an oral slot to present my model (I was once offered a poster slot in an international ED conference). This is despite the fact that current theoretical frameworks and aetiological models for eating disorders have near zero explanatory power and quite often airtime is given to many very questionable theoretical models.
In the meantime, my original theoretical paper describing SCH has been cited 195 times and most evolutionary texts consider it to be the best evolutionary theoretical formulation for EDs. Personally, I consider the Extended Mismatch Model (Ayton & Ibrahim, 2020; Rantala et al, 2019) which incorporates the SCH but also adds a variety of other mismatches to be the ‘state of the art’ in evolutionary theorising on EDs.
Unlike the SCH, my other 2 evolutionary theoretical models (for OCD and schizophrenia) have not yet been subjected to empirical testing but both remain extant in the literature and continue to gather citations.
I published the OCD paper in 1999 together with a colleague (Karel de Pauw). The core of the model proposes that OCD arises from an overactive harm prevention system that exists in all humans. I called this system the ‘Involuntary Risk Scenario Generating System.’ The function of this system is to produce risk scenarios in the form of intrusive thoughts that are aversive and lead to avoidance of such risks at a future time. In its normative, physiological form, this is adaptive and leads to adaptive learning of risk avoidance and harm prevention behaviour for self and significant others. In its extreme (overactive, pathological) form it leads to excessive and unnecessary risk scenarios in the form of obsessional thoughts. The compulsive rituals are actions designed to neutralise the risk scenarios and inhibit or shut down the system. However, in the pathological overactive state of OCD, the feedback loop fails, and the aversive risk scenarios continue, resulting in distress and functional impairment. The model clarifies the status of obsessional thoughts as risk scenarios to be prevented and warning signals to be avoided, and not perverse desired or desirable impulses. This helps us think more clearly about suitable animal models (which currently, are erroneously based on impulsive and not compulsive behaviour).
Again, despite the fact that mainstream psychiatry currently, has few, if any, non-reductive models of OCD, it has completely ignored this hypothesis and, to my knowledge, even after a quarter of a century, not a single standard psychiatric text has referenced it. While at the same time, it has been cited over 130 times in the evolutionary and psychology literature.
The 3rd evolutionary model I have been associated with concerns schizophrenia. The Outgroup Intolerance Hypothesis (OIH) was conceived as a result of the observation that migrants, urban dwellers and ethnic minorities have a higher risk of schizophrenia. These findings combined with the now well documented new epidemiology of schizophrenia that shows that schizophrenia has widely varying rates across societies and populations (that can vary up to 30-fold).
This raised a number of questions for me:
Is the risk of schizophrenia related to modern conditions?
Are there studies of schizophrenia in hunter gatherers?
What aspects of the modern environment represented the ‘toxic stress’ that plays an aetiological role in the causation of schizophrenia?
The OIH proposes that some of the toxic stress involves living among many strangers together with insufficient contact with or support from kin or ingroup members. The subsequent epidemiological research showing that low same group ethnic density in a given neighbourhood is a risk factor for schizophrenia (now replicated in several studies) further supported these contentions. The OIH was published in 2 papers in 2011 and 2014 and my co-author at the time was my then higher trainee Mohammed Abbas. The OIH was further elaborated through the work of 2 core trainees (Costa Savva and Ben Griffin) with whom I collaborated. This resulted in the Modified Aberrant Salience Hypothesis (MASH) that combined Kapur’s Aberrant Salience Hypothesis with the OIH thus providing both a proximate explanation (dysfunctional salience network) and an evolutionary explanation (mismatch). In addition to the outgroup status, the toxic stress model was extended to adverse childhood experiences that create the vulnerability to future outgroup status effects through the miscalibration of the salience network, leading to schizophrenia in vulnerable individuals. The MASH article was published in Evolutionary Psychological Science in February 2024 and has already been cited once!
The Modified Aberrant Salience Hypothesis (MASH) for Psychosis
It is a real pleasure to introduce to our readers, Dr Costa Savva and Dr Benjamin Griffin who recently published a paper titled: “Towards a Unified Account of Aberrant Salience in Psychosis: Proximate and Evolutionary Mechanisms” This fresh take on evolutionary mechanisms in psychosis blends findings in systems neuroscienc…
How does your theory/model for eating disorders improve on the other theories in the field?
How does it incorporate wider disordered eating, e.g. bulimia nervosa and eating disorders in males?
The SCH makes a number of predictions. They include:
That AN and BN patients will show higher levels of competition for mates compared to control
Higher female autonomy in any society will be associated with higher risk of EDs
Societies with high fertility will show lower levels of EDs
Exclusive lesbians will show lower levels of EDs whereas exclusive male homosexuals will show higher levels of EDs
The extended mismatch hypothesis makes a number of further predictions primarily relating to nutrition.
Current ED theories do not explain the cardinal features of EDs:
a. Why predominantly females?
b. Why predominantly females of reproductive age?
c. Why the particular geographical distribution?
d. Why the increase in recent times?
The SCH uniquely provides an explanation for these peculiar features.
Furthermore, it provides an explanation for the 2 distinct ED syndromes males present with. The female-typical version based on the ‘drive for thinness’ afflicts homosexual males disproportionately. The other version is the male-typical version ‘drive for muscularity’ (where the patient presents with the feeling that their upper body is too small and they want to get it bigger); which afflicts mainly heterosexual males. Only the SCH has an explanation for both based on intra-sexual competition. In the drive for thinness, homosexual men employ a similar strategy to heterosexual females in displaying signs of youth and physical attractiveness that males find attractive. In the drive for muscularity, males seek to display upper body strength which has been important through human evolutionary history as a competitive signal to other men as well as an attractor for female mates. Hence, intra-sexual competition can be a useful explanatory framework that incorporates all these variants.
What are you working on currently? And what's in store for you in the near future?
I think its very exciting that there are so many areas in psychiatry still barely touched by evolutionary thinking. So, there is much to do both theoretically and empirically. Being retired, and not working within an academic organisation limits my ability to participate in empirical research. However, I welcome opportunities for collaboration in such studies if and when they do come up.
However, I am very active in writing and publishing theoretical work in collaboration with colleagues and sometimes on my own. Subjects that I am either thinking about or actively working on include: Evolution and research; Evolution and sexual jealousy; Anxiety miscalibration and hormesis; A novel phylogenetic theoretical model for the evolution of human personality types; Evolution and outcome measurement; Evolution and Cross-Cultural Psychiatry; Evolution, Sickness and Healing etc
You have been a leading light in the field and have been championing the wider adoption of evolutionary psychiatry.
Where do you see evolutionary psychiatry will go in future, what kind of barriers do you foresee?
You are very kind. Evolution is certainly a passion of mine and since I have retired from full time clinical work I have had more time to devote to it both administratively and academically. Yogi Berra, the baseball legend once said: ‘Its hard to make predictions especially about the future’. So, its hard to say how the future is going to pan out for evolution in psychiatry and medicine. With the pioneering work of evolutionists such as Randolph Nesse, Alfonso Troisi, Martin Brune and others, and with the formation of EPSIG (UK) and later the Irish EPSIG there has been a slightly increased acceptance of evolutionary ideas in mainstream psychiatry publications such as ‘World Psychiatry’ and the BJPsych (and its sister journals). Will this continue? Its hard to say.
One particular challenge that EP must meet is to make the move from theory to empirical data and then to clinical practice. EP is currently a largely theoretical pursuit. I think our colleagues in mainstream psychiatry are mainly clinical practitioners interested in what makes a difference to their patients. This will the challenge that the next generation of evolutionists like yourself must meet.
Thank you very much for talking with us Riadh, it has been an absolute pleasure. If people would like to follow you and your work where should they go?
Research Gate Riadh Abed FRCPsych
Twitter/X @RiadhAbed1
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I would love to read a more detailed explanation of the theory that schizophrenia is related to outgroup intolerance. I have been diagnosed with schizotypal personality disorder and am extremely eager to understand it. The presentation of the theory in this interview is very compressed, and I struggle to understand it.