The biopsychosocial model: Reality check

Since its fortieth anniversary, George Engel’s biopsychosocial (BPS) model has enjoyed renewed attention from psychiatry. In 2018, British psychiatrist Linda Gask (2018) penned a heartfelt and personal corrective, In defence of the biopsychosocial model, concluding ‘… the biopsychosocial model is, and remains, a model for the whole of medicine – not just psychiatry’.

A wide-ranging work by Bolton and Gillett (2019) aims to rejuvenate Engel’s concept, recasting it as a biopsychosocial theory to give a ‘unified science’ of health and illness. Porter (2020) suggested it should be seen as a ‘biopsychosocial spectrum’, with separate conditions located at different points on the spectrum according to the aetiological factors that contribute to them. The well-known American psychiatrist and editor, Ronald Pies, has never been in any doubt:

… academic psychiatry – for at least the past 30 years – has advocated a ‘bio-psycho-social’ model of mental illness, as originally proposed by Dr George Engel … This position has been quite consistent … (Affective) disorders are best understood using a bio-psycho-sociocultural model, which has been the mainstay of academic psychiatry for over 30 years. (Pies, 2019)

Currently, the number of published papers on the topic of the BPS model is rising steadily, even exponentially. A PubMed search shows that in 1977, there was one paper, Engel’s original. The table shows how citations have increased since then:

1977	1978	1979	1980	1985	1990	1995	2000	2005	2010	2012	2014	2016	2017	2018	2019
1	2	3	11	10	22	29	46	90	126	163	211	247	264	279	319

Early uptake of the model was largely restricted to psychiatrists, to the extent that it was seen more or less as defining psychiatry as a discipline (see McLaren 2010 [1998] for details). However, it should not be forgotten that, however many psychiatrists embraced his notion, Engel was a gastroenterologist, not a psychiatrist, and he never mentioned mental disorder. Moreover, current interest in his work is largely restricted to English-speaking countries, and most of the recent increase shown in the table derives from non-psychiatric fields, such as chronic illness, disability and community health.

Be that as it may, the best we can say about the interest in his idea is that it is misplaced, as Thomas Huxley noted, ‘The great tragedy of science is the slaying of a beautiful hypothesis by an ugly fact’. Agreed, Engel’s idea of a unified model of brain–mind interaction has a lot to recommend it; the ugly fact is that he never wrote it. As long ago as 1998, it was shown that George Engel did not write a model, or theory, or anything of any intellectual significance addressing the question of integration of mind and body in health or disease (McLaren, 2010 [1998]).

Of the authors cited above, only Gask mentioned this paper, somehow missing the central point, that her favourite model doesn’t exist. The others simply ignored it. Gillett, for example, has a PhD in philosophy and is a professor of bioethics at a prestigious university (Otago). How, then, when he is unable to produce a copy of it, can he claim that ‘The (BPS) model is popular and much invoked in clinical and health education settings and has claim to be the overarching framework for contemporary healthcare’? This applies equally to Pies, who was offered the same challenge but has conspicuously failed to respond.

Bolton and Gillett’s work shows an interesting point in that, omitting to mention that the model doesn’t exist, they devoted most of the first chapter to arguing that psychosocial factors are influential in a wide variety of medical conditions. Their effort was entirely beside the point: the question they needed to answer was whether Engel wrote an integrative model of body and mind, not whether it would be a good idea.

Porter took it further, suggesting that the BPS model should be envisaged as a spectrum, with biology at one end and psychosocial factors at the other. That too doesn’t work: as every first year mathematics student knows, it is not possible to chart three parameters on a single axis. Separate factors can only be graphed on separate axes, meaning three. In any event, while it may have some descriptive value, a spectrum, or continuum, as it used to be known, explains nothing.

Let me declare my position: I strongly agree with Engel’s contention that biological reductionism is dehumanising and demeaning. I totally support the idea that ‘… a bio-psycho-sociocultural model, (should be) the mainstay of academic psychiatry’, not just for 30 years, but for as long as there are psychiatrists. For many years, I have been working to just that end (McLaren, 2010 [1998]). My grievance lies with the steady stream of influential psychiatrists claiming that Engel penned such an explanatory model when, as a matter of demonstrated fact, he didn’t.

In his Critical Notice on Teilhard de Chardin’s The Phenomenon of man (Medawar, 1961), Peter Medawar, the Nobel laureate immunologist, said: ‘(The) author can be excused of dishonesty only on the grounds that, before deceiving others, he has taken great pains to deceive himself’. That more or less sums up where psychiatry stands vis-à-vis Engel’s biopsychosocial ‘model’. As long as psychiatrists believe the hard work has been done, it won’t get done. Inevitably, self-deception leads to intellectual complacency.