Psychobiological Processes in Health and Illness

Kate Hamilton-West

• Publisher: SAGE Publications Ltd
• Year: 2010
• Print ISBN: 9781847872449, 9781847872432
• eBook ISBN: 9781446244487
• Edition: 1
• Topic: Psychology
• Subtopic: History & Theory in Psychology
• Index: Psychology

?A fantastic contribution to health psychology. My PhD students and medical students are instructed to read it (not often I recommend books these days). It feels like the field has been waiting for this for a long time? - Dr Lis Cordingley

Senior Lecturer in Health Psychology, School of Medicine, University of Manchester

 

An engaging introduction to the interrelationships between mind and body across a broad range of topics including infectious illness, autoimmunity, cancer and pain. Taking a biopsychosocial approach, it brings together research from a number of disciplines including health psychology, psychoneuroimmunology and behavioural genetics.

 

Students are encouraged to consider how advances in psychobiological research can help us to uncover the true complexity of links between psychological, biological and social processes with respect to implications for health and how such advances can inform the development of interventions and treatment.

THE MIND-BODY CONNECTION

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OVERVIEW

This chapter presents some key concepts relevant to an understanding of psychobiological and psychosocial processes in health and illness. Although the focus of this book is on psychobiological processes, the two are very closely related, so it is important to acknowledge the role of psychosocial processes before proceeding further.

The biopsychosocial model of health is introduced and contrasted with the biomedical model of health. This discussion is set in the context of changing conceptualisations of mind and body and the emergence of ‘new’ fields of enquiry, including health psychology, behavioural medicine and psychoneuroimmunology. In so doing, we consider how advances in research are helping us to uncover the true complexity of links between psychological, social and biological processes with respect to their implications for health and how such advances may inform the development of new approaches to the treatment and prevention of illness.

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LEARNING OUTCOMES

By the end of this chapter you should be able to:

• explain what is meant by ‘psychobiological processes’
• explain what is meant by the terms ‘health’, ‘illness’ and ‘disease’
• explain what is meant by ‘normality’
• discuss global trends in disease, mortality rates and the causes of ill health
• describe the biopsychosocial model of health and compare it with the biomedical model
• discuss the influence of the biopsychosocial model on the development of new disciplines
• describe and differentiate between these disciplines
• describe the process of defining and measuring a psychological construct
• explain why psychobiological processes are important for understanding, preventing and treating disease and illness.

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CHANGING CONCEPTUALISATIONS OF MIND AND BODY

1.1 This book is entitled Psychobiological Processes in Health and Illness, so, before proceeding further, it is useful to begin by considering what exactly we mean by the terms ‘psychobiological’, ‘health’ and ‘illness’.

While the latter two terms may seem intuitive, there has been considerable debate over the years regarding the definition of both ‘health’ and ‘illness’, and the distinction between health, illness and disease. Further, to explain the term ‘psychobiological’, we need to break the word down into its two constituent parts – ‘psycho-’ ‘and ‘biological’. In this chapter, then, we also consider why both psychological and biological processes are relevant to an understanding of health and illness and how these two types of processes have come to be combined into a single term.

1.1.1 DEFINING HEALTH, ILLNESS AND DISEASE

What does it mean to be healthy? Well, we could start by considering that health indicates a lack of illness or a lack of disease – you are not ill, therefore you are healthy. This is a difficult starting point, though, since both illness and disease themselves are poorly defined (as discussed further below). Also, are you in optimum health if you are not diseased or is health something more than absence of illness?

The World Health Organisation, for example, has defined health as ‘a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity’ (WHO, 1946: 100). According to this definition, though, we would probably all be considered unhealthy. For example, you may not consider yourself completely healthy because you get out of breath walking up stairs or are unable to complete a marathon. At what point is our well-being less than complete?

Perhaps what really matters is the individual’s ability to perform daily functions, such as continuing to go to work, raise a family or drive a car. Disease does not necessarily preclude normal daily functioning, so what about a patient with a terminal illness who is still able to go to work – is this person healthy or ill?

Perhaps you could consider yourself to be a healthy person even if you are, from time to time, afflicted with a runny nose, headache or sore throat. If so, why do these symptoms not constitute a lack of health? Maybe, then, we should overlook symptoms that are highly prevalent in the population and consider whether or not the individual experiences symptoms that are abnormal.

This, too, raises problems. First, how do we define ‘abnormal’ and, second, is ‘abnormal’ necessarily unhealthy? In relation to the former point, what is ‘normal’ in terms of physical, social and mental functioning depends on a wide range of factors, including the individual’s age, gender, social status and culture. In relation to the latter point, it is clear that an individual can fall outside the range of statistical normality without necessarily being ill. For example, Veatch (1981) points out that the seven foot tall basketball player is not considered ill, nor are people with freckles, although both can be considered to be statistically abnormal (see Box 1.1).

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BOX 1.1

Statistical normality

Many human characteristics follow a normal distribution. This means that most individuals will be at or around the average value for the group (such as being the average height for a man or woman). The frequency of a particular measurement decreases as the distance from the average value increases (there are few very short or very tall people, but many people are of roughly average height). If measurements are plotted on a graph, with the measurement scale on the X axis and frequency on the Y axis, this results in a bell-shaped curve, or ‘Gaussian function’.

Individuals falling at the tail ends of the distribution are considered statistically abnormal. The cut-off value used most commonly is 95 per cent – that is, scores outside of the 95 per cent range (the top 2.5 or bottom 2.5 per cent) are abnormal.

It is important, however, to consider the ‘reference group’ used to calculate the normal range. For example, many people will appear abnormal if compared against norms for a different cultural group or age group or gender.

Many indicators of health (such as the level of glucose or cholesterol in the blood) follow a normal distribution. Individuals with values outside the normal range (for healthy individuals) are considered abnormal, although this does not necessarily indicate that these individuals are unhealthy. Many measures of psychological characteristics (such as intelligence, aggression) yield scores that are approximately normally distributed – that is, there are lots of people of roughly average intelligence, but few individuals with exceptional genius. As with indicators of physical health, abnormal scores on psychological measures do not necessarily indicate a need for treatment.

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Perhaps, then, we should consider the individual’s evaluation of his or her apparent symptoms. Are they abnormal for the individual and a source of distress or are they typical, tolerable? Thus, being unable to run a marathon could constitute evidence of ill health if the individual is normally able to run the marathon very easily and experiences distress in relation to this loss of physical fitness. Is this person really ill, though, or do they simply need to adapt their training routine?

It is clear, then, that although we may know in very general terms what we mean by the word ‘health’, providing a precise definition for this concept is far from straightforward. Further, it is evident that the related constructs of ‘illness’ and ‘disease’ are similarly ambiguous.

Engelhardt (1981: 39) writes that ‘the concept of disease is an attempt to correlate constellations of signs and symptoms for the purposes of explanation, prediction and control’, while Boorse (1977) proposes that a disease is only an ‘illness’ if it is serious enough to be incapacitating and therefore undesirable for the bearer, a title to special treatment and a valid excuse for normally criticisable behaviour. Thus, ‘the concept of disease acts not only to describe and explain, but also to enjoin to action. It indicates a state of affairs as undesirable and to be overcome’ (Engelhardt, 1981: 33).

In general, then, although these constructs are very difficult to define, a number of conclusions can be drawn:

• health is essentially an evaluative notion, based on adherence to physical, social and mental ‘normality’, although what is normal depends on a range of factors, including age, gender, culture and social status
• illness can be considered as a deviation from ‘normality’ that is perceived by the patient as distressing and entitling them to special treatment
• disease can be considered as an organising construct for explaining and responding to constellations of symptoms
• while health is a positive state of affairs, to be promoted and aspired to, both illness and disease are considered as negative states, to be treated or otherwise overcome.

1.1.2 THE ROLE OF PSYCHOLOGICAL PROCESSES

Thoughts, feelings and behaviours affect our health and well-being. Recognition of the importance of these influences on health and disease is consistent with evolving conceptions of mind and body and represents a significant change in medicine and the life sciences.

Baum & Posluszny, 1999: 138

It should be evident from the preceding discussion that psychological processes (thoughts, feelings and behaviours – also known as cognitions, emotions and actions) play an important role in health. First, as health is an evaluative notion, the same symptoms may be interpreted in different ways by different people. The individual’s interpretation of these symptoms will influence behaviours such as seeking medical help, over-the-counter remedies or alternative therapies, and these behaviours are likely to influence health outcomes.

Further, the very causes of ill health in humans are often psychological in nature, setting us apart from other animals. As Kass (1981: 19) points out, ‘other animals do not overeat, undersleep, knowingly ingest toxic substances, or permit their bodies to fall into disuse through sloth, watching television and riding about in automobiles, transacting business, or writing articles about health.’

The way we respond to stress as a species also highlights the role of psychological variables in the aetiology of illness. For example, Sapolsky (2002) explains that, while lions or zebras mobilise a stress response when faced with a physical threat, humans have a unique propensity to worry themselves sick by dwelling on anticipated stressors, such as what to say in a job interview.

The recognition that health is the result of a combination of biological, social and psychological factors, is often referred to the biopsychosocial model of health (Engel, 1977), where the term ‘model’ indicates a ‘complex integrated system of meaning used to view, interpret and understand a part of reality’ (Veatch, 1981: 523). Engel (1977) contrasted this model to the (then dominant) biomedical model, which assumes disease to be fully explained by deviations from the norm of biological (somatic) variables.

These two models not only provide very different frameworks for interpreting and understanding illness but also give rise to different approaches to treatment and prevention. The biomedical model, with its focus on medical responses to biological alterations, has resulted in the development of drugs and vaccines that have contributed to a dramatic decline in mortality rates in ...

Table of contents

• Cover Page
• Title Page
• Copyright Page
• Contents
• Preface
• Acknowledgements
• 1 The mind-body connection
• 2 The link between stress and illness
• 3 Positive processes in health and illness
• 4 A healthy disposition
• 5 Pain
• 6 At risk populations
• 7 Psychobiological interventions
• 8 methodological issues in psychobiological research
• 9 Summary and future directions
• Glossary
• References
• Index