Book Review by Neil Vickers
Derek Bolton and Grant Gillett, The Biopsychosocial Model of Health and Disease: New Philosophical and Scientific Developments. Houndmills: Palgrave, 2019. ISBN 978-3-030-11899-0. This book is an open access book, that can be downloaded free of charge.
The biopsychosocial model of health and disease (BPSM) is the nearest thing academic medicine has to an ideology. And in recent years, dissenting voices have been raised against it. In 2009, Nassir Ghaemi, a psychiatrist based at Tufts University, published a book entitled The Rise and Fall of the Biopsychosocial Model. For Ghaemi, the biopsychosocial model enabled psychiatrists to avoid confronting the very real disagreements dividing them on the causes of mental illness. Everybody knows that biology, psychology and the social world have a bearing on mental health. The BPSM, in his view, allowed practitioners with different theoretical allegiances to ignore each other’s views.
Although versions of the BPSM have been circulating since at least the 1920s, the term is usually traced to an article by George Engel from 1977.1 Engel contrasted the BPSM with biomedicine. Biomedicine defined disease solely in terms of somatic parameters. Molecular biology was its basic scientific discipline, leaving no room ‘for the social, psychological and behavioural dimensions of illness’. The BPSM was intended to remedy that shortcoming. Despite the immense good will of healthcare professionals, the BPSM at first boasted few scientific breakthroughs to rival those of biomedicine. Psychosocial risk factors are notoriously vulnerable to heavy and often unknown confounding by other variables. To take but one example: for decades, stress was thought to be the main cause of peptic ulcers, until H. Pylori was discovered in 1983. Now in fact, around 15% of cases of peptic ulcers occur in patients where there is no evidence of H. Pylori and stress is still known to be a risk factor. So the psychosocial risk hasn’t disappeared but it has assumed a more complex identity. Also, the mechanisms by which psychosocial factors take effect were and still are poorly understood, compared with biological ones, though over the last 40 years massive strides forward have been taken .
Now, a new book has appeared defending a version of the BPSM, drawing on Engel’s original, but updating it in the light of substantial developments in the sciences and philosophy since the 1980s. Its authors are Derek Bolton, a professor of psychopathology and philosophy at the Institute of Psychiatry, Psychology and Neuroscience in London, and Grant Gillett, a neurosurgeon and bioethicist based at the university of Otago in New Zealand.
Evidence for the existence of biopsychosocial causation has proliferated since Engel’s paper, mostly in the form of risks to population health. Research on the social determinants of health, the Adverse Childhood Events study in the US, and large-scale epigenetic studies such as the Dunedin Study all support biopsychosocial causation. Biopsychosocial factors are also implicated in the way we adapt to many long-term conditions.
For Bolton and Gillett a general account of the BPSM cannot be a guide to clinical practice in the way that Engel hoped. Rather, clinical versions of the BPSM will differ by condition. The BPSM of cardiovascular disease will be different from the BPSM for schizophrenia. A general model is still required philosophically, they say, to define ‘the foundational theoretical constructs—the ontology of the biological, the psychological and the social— and especially the causal relations within and between these domains.’
When Engel published his article, biomedicine effectively treated biochemistry as a branch of physics. Biological causation was assumed to be reducible to physico-chemical causation. But this is no longer tenable, say Bolton and Gillett. Of course, biological organisms exploit physics to extract energy for functioning, but their ability to do so depends on a range of interacting regulatory mechanisms. In modern biology, life is increasingly defined in terms of information transfer. ‘Information’, they write, ‘is not like energy, which is covered by the energy equations of physics and the corresponding … equations of chemistry. Rather, information is more like a switch, turning processes off and on, hence being representable typically by 0s and 1s.’ Regulatory control mechanisms never contravene the energy equations of physics and chemistry (because nothing ever does), but they represent a separate source of causation from these. And it turns out that regulation has wide application not only in biology, but also in psychological and social domains. Bolton and Gillett argue that it supplies a grounding for a unified model of the bio, the psycho and the social.
Having redefined the bio- Bolton and Gillett then move on to the psychosocial. I have space to pick out just one of their arguments. The amount of agency we have impacts directly on our health. Michael Marmot holds that ‘it is not simply position in the hierarchy that accounts for worse health among individuals of lower status … but what position in the hierarchy means for what one can do in a given society: the degree of autonomy and social participation.’ To exercise agency, we require recognition of our right to do so. This is why intersubjectivity is so important. We need others to ratify our experience. Our biology is intimately involved in this process. We do this by regulating one another’s heart rate, blood pressure and cortisol levels. Where the individual is denied agency, illness becomes more likely. The key point is that modern biology, informed by genetics and neuroscience effectively breaks down previous categories of biological, psychological, environmental and the social.
I have barely scratched the surface of this very rich book. Its four crisp chapters contain a model of cross disciplinary research and dialogue and will be of interest to anyone interested in what a modern version of the BPSM might look like. And what’s more, thanks to the Wellcome Trust, the whole book can be downloaded free of charge.
Neil Vickers is professor of English Literature and the Health Humanities at King’s College London.
Declaration of interest: I am writing a book with Derek Bolton, one of the authors of the book mentioned in this review. The book is about the impact of major illness on our membership of groups.
 Engel GL. The need for a new medical model: a challenge for biomedicine. Science 1977; 196: 129–36.