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Institute of Mental Health



What is mental health?

By tonydavid, on 13 August 2019

All of a sudden, everyone is talking about mental health. But what does it mean? First of all, is it just a euphemism for mental illness which avoids (yet perpetuates) stigma? Are mental health and mental illness poles on a continuum? And if so, how do you decide when good health passes into ill health?

If we look at general health – physical health – we might learn some useful lessons. In 1948, the World Health Organisation (WHO) defined Health as: “A state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.” This was regarded at the time as bold and progressive, perhaps part of the spirit of post war optimism. Now at best, it seems utopian. At worst it implies medicalisation of all aspects of life. A group of international but mostly Dutch public health physicians, researchers, policy makers and educationalists [Huber et al, 2011] have recently proposed that a new definition of health based on “the ability to adapt and to self manage” be considered. Their initiative is driven by the fact that the health challenges of the 21st Century are dominated by chronic conditions and ageing which are inescapable for the majority so should encourage adaptation rather than eradication. Indeed it is a truism that for most people, ageing may not be great but at least it is better than the alternative. Huber and colleagues also suggest that physical, mental and social domains be separated when definitions of health are contemplated.

Another problem with definitions of health which include notions of function is that it depends so much on what resources are available to the individual, in order to for example, overcome or manage disability or adapt to change.

In reviewing definitions of mental health I am struck by how they tend towards the mystical. Returning to the WHO, their 2014 definition of mental health is: “A state of well-being in which every individual realizes his or her own potential, can cope with the normal stresses of life, can work productively and fruitfully, and is able to make a contribution to her or his community.” Terms like ‘a sense of coherence’; ‘self actualization’ and ‘mastery’ crop up in other proposed definitions [see Maxwell et al, 2015 for approaches to this issue]. I am minded to call these states ‘bliss’ rather than mere ‘health’. This again merits concern about over-medicalisation. If health (mental or physical) approaches a state of perfection it dooms the rest of us to the status of ill health. Feeling pain – from time to time if predictable and not extreme – is surely healthy. Same for fatigue. Same for anxiety and depression.

As for well-being – another term often bracketed with health and just as slippery – definitions are elusive. It is economists like Richard Layard, rather than mental health professionals, who are most comfortable with ‘well-being’ sometimes simplifying it further to ‘happiness’. Their work has shown that basic needs – food, shelter, safety – are a prerequisite but above that threshold it is a highly subjective phenomenon and moreover, it is highly relative. Our sense of well-being is strongly associated with our social status and wealth relative to others rather than in absolute terms. While we would be foolish to ignore this window into human nature, it provides a problematic basis for a definition of health (or illness) which, as I see it, at least ideally should be somewhat ‘objective’.

My preferred stance is to expand the range of what is regarded as healthy, whether it be physical or mental and restrict what is regarded as unhealthy. It means that the former no longer feels like an unattainable goal but something broader, more recognisable, imperfect, ‘good enough’. This holds back the encroachment of pathology into everyday life thus avoiding iatrogenic illness, expensive unnecessary treatments and fear. However, even if it is agreed that the transition between health and illness occurs way up toward the ill end of the spectrum it still leaves the thorny issue of whether a line should be drawn – creating a category of illness or ill people – and if so, where exactly should it be drawn.

I have argued [David, 2010] that there are dangers in not drawing a line somewhere, while acknowledging that, in the mental health field, this is unlikely to be carving nature at its joints. The main one being that diagnosis becomes not just arbitrary but up for grabs – by Big Pharma, politicians and anyone else. This in turn is likely to lead again to over-medicalization and sometimes discrimination. From a practical point of view, planning health services and doing research are hampered unless the health problem – the diagnosis – is clearly and reliably defined and communicable.

Finally should we be separating mental and physical health? Some would argue that this is hopelessly dualist. Most people agree that our minds arise out of and are entirely dependent on our bodies. There are biological as well as psychological and social elements within all psychiatric disorders and indeed all diseases. The biopsychosocial model is an important guide and underpinning philosophy here [see Bolton and Gillett, 2019]. Let’s stay with dualism and instead of conceiving of a single health-illness dimension, we consider two orthogonal dimensions, like the points on a compass with mental health-to-ill health running from west to east and physical health-to-ill health running north to south. A person is unlikely to feel in good mental health if they are in poor physical health and vice versa. I would imagine most patients would aggregate in the south east quadrant of the graph while I would hope that most of us spend most of our time in the ‘north west’.

Just as ‘Peace’ may be defined as “the absence of war”, so ‘Health’ – contrary to the WHO – may be usefully and simply ascribed to “the absence of disease”. It’s actually not a bad place to start.


Tony David, Director, UCL Institute of Mental Health. August 2019




Huber M, Knottnerus JA, Green L, Horst H, Jadad AR, Kromhout D, et al. How should we define health? BMJ 2011; 343 :d4163

Manwell LA, Barbic SP, Roberts K, et al. What is mental health? Evidence towards a new definition from a mixed methods multidisciplinary international survey BMJ Open 2015;5:e007079. doi: 10.1136/bmjopen-2014-007079

David AS. Why we need more debate on whether psychotic symptoms lie on a continuum with normality. Psychol Med 2010, 40: 1935-42.

Bolton D, Gillett G. The Biopsychosocial Model of Health and Disease. Palgrave Pivot, Cham, 2019, 1-145.

UCL Institute of Mental Health has a blog

By Maria Thomas, on 9 July 2019

Welcome to UCL Institute of Mental Health (IoMH) blog.

Here we will invite guests and IoMH team to contribute their thoughts and research in current mental health topics.

You can find out more about the Institute on our website: https://www.ucl.ac.uk/mental-health/

Watch this space!