Eating Disorders and the Brain

Bryan Lask, Ian Frampton

• Publisher: Wiley
• Year: 2011
• Print ISBN: 9780470670033
• eBook ISBN: 9781119973645
• Edition: 1
• Topic: Medicine
• Subtopic: Anatomy

Why is the brain important in eating disorders? This ground-breaking new book describes how increasingly sophisticated neuroscientific approaches are revealing much about the role of the brain in eating disorders.  Even more importantly, it discusses how underlying brain abnormalities and dysfunction may contribute to the development and help in the treatment of these serious disorders.

• Neuropsychological studies show impairments in specific cognitive functions, especially executive and visuo-spatial skills.
• Neuroimaging studies show structural and functional abnormalities, including cortical atrophy and neural circuit abnormalities, the latter appearing to be playing a major part in the development of anorexia nervosa.
• Neurochemistry studies show dysregulation within neurotransmitter systems, with effects upon the modulation of feeding, mood, anxiety, neuroendocrine control, metabolic rate, sympathetic tone and temperature.

The first chapter, by an eating disorders clinician, explains the importance of a neuroscience perspective for clinicians. This is followed by an overview of the common eating disorders, then chapters on what we know of them from studies of neuroimaging, neuropsychology and neurochemistry. The mysterious phenomenon of body image disturbance is then described and explained from a neuroscience perspective. The next two chapters focus on neuroscience models of eating disorders, the first offering an overview and the second a new and comprehensive explanatory model of anorexia nervosa. The following two chapters offer a clinical perspective, with attention on the implications of a neuroscience perspective for patients and their families, the second providing details of clinical applications of neuroscience understanding. The final chapter looks to the future.

This book succinctly reviews current knowledge about all these aspects of eating disorder neuroscience and explores the implications for treatment.  It will be of great interest to all clinicians (psychiatrists, psychologists, nurses, dieticians, paediatricians, physicians, physiotherapists) working in eating disorders, as well as to neuroscience researchers.

Chapter 1

Why Clinicians Should Love Neuroscience: the Clinical Relevance of Contemporary Knowledge

David Wood

Ellern Mede Service for Eating Disorders, London, UK

1.1 Introduction

Clinicians at times appear to have an uneasy relationship with neuroscience. At a superficial level it may seem that there might be little need to question whether the relationship between neuroscience and clinical work is problematic. However, despite their now reasonably lengthy coexistence, there still exists a tension between these two fields of endeavour. This leads to misunderstanding, and even distrust, which inhibits the undoubted opportunities—if not necessity—for creative and fruitful interaction. Questions are still asked within the clinical domain about the relevance of neuroscientific study, and neuroscientists can become so absorbed and fascinated with their subject that they lose sight of the clinical relevance of what they are studying. It is the contention of this chapter that the relationship between neuroscience and clinical work should not be problematic, and that those on both sides of the divide can learn, not only to live together, but also to admire each other's concepts.

Why should we love neuroscience? Of course, telling someone what he or she should love is a supremely arrogant and rather fruitless enterprise, as anyone who has tried to get their child to love eating, say, oysters will know. But neuroscience is not just an acquired taste; it does not require great familiarity to appreciate its qualities. It is certainly possible to comprehend the wonder, awe and excitement that this field of endeavour can evoke without having to fully understand its every detail. And without some appreciation of the currently available knowledge about the brain, clinicians are in danger of setting off down many a blind alley in carrying out clinical practice.

In order to support this argument, it is first necessary to review some fundamental problems. This will be followed by a brief, and highly condensed, overview of some current neuroscience facts, which will then be reviewed within the context of current developments within the field of eating disorders.

1.2 The Legacy of Mind–Body Dualism

The tension between clinical work and neuroscience would seem to be supported by the continuing predominance of dualistic thinking, not only within scientific discourse, but in postmodern culture more generally. Given the lengthy history of dualism, from Plato, down through Descartes, to William James and beyond, it is not surprising that it does not easily throw in the towel. The fundamental problem with which Homo sapiens has wrestled for so long is how can we reconcile our sense of ourselves as free agents, capable of choosing our path through life, with a notion of our bodies (including our brains) being constructed of physical stuff that obeys the deterministic laws of nature.

Plato considered that humans had earthly bodies and ethereal souls, and put the mental properties of reason, desire and appetite firmly in the domain of the soul. Indeed, Aristotle thought that the brain was merely an organ for cooling the blood and that the heart was really where the passions lay. Continuing in the Platonic tradition, Descartes, in his pamphlet ‘On the Passions of the Soul’ [1], decided that bodies were made up of stuff such as blood, muscles, nerves and so on, and were controlled by ‘bodily spirits’, whereas our thoughts and our passions belonged to the soul, and our mental experiences were instances of awareness of the movements of the bodily spirits via contact between soul and body in the pineal gland. It is hard to know what Plato would have made of someone whom we might now diagnose as suffering from anorexia nervosa (AN). It is reasonable to surmise that he would probably not have considered them to be suffering from an illness. More likely he would have marvelled at the way in which they were able, with so much stoicism, to conquer their appetites and disentangle themselves from the world of the senses, thus liberating their ethereal soul from the constraints of the material body. For Plato and his successors, the passions were seen as something that needed to be subjugated, brought under control, an idea that presages the current interest in emotion regulation and AN.

Dualist accounts, particularly of emotion, have been hard to shake off, and continue beyond Descartes, through Locke and Hume, to William James, Popper and Eccles [2], and even perhaps to some elements of modern emotion theory such as the somatic marker hypothesis [3–6]. They remain alive and well in some clinicians' apparently unshakeable belief that AN is a ‘brain’ disease, just as in others' similarly unshakeable beliefs that it is a ‘mental’ illness without physical correlates. But to argue either way implies a distinction between brain and mind that really can no longer be justified.

In essence, all dualist accounts come up against the difficulty that there is no convincing explanation of how, if brain and mind are of different stuff, they can interact, and how mental events can have a causative role in behaviour. There would seem to be little doubt that despite Cartesian dualism's refusal to go quietly, the general direction of neuroscientific endeavour has been inexorably towards a monist1 position. However, this has brought with it new difficulties.

1.3 Free Will and Determinism

Despite the issue of free will and determinism having an indisputable and central relevance to ethical and legal debates about whether the state and its representatives have the right to intervene when a patient with AN asserts her right to starve herself to death, there is virtually no discussion of it in the clinical literature. The assertion that human beings are free2 to choose their own destiny can really only be upheld if one espouses a dualist position. To be free is only possible if the mind is free of the body. It seems reasonable to suppose that much of the objection to a monist position arises because of fear of confronting the logical, determinist consequence of that position: that is, we are actually not free to choose, in the sense that we cannot choose whatever we want.

This issue generates a number of complicated problems in relation to ‘mental’ illness. For instance, if we define a wish (to exercise the ‘freedom’) to hurt oneself, or to be reckless of danger (such as when one is refusing to eat), as a characteristic of a mental illness, then we are denying that it is an act of free will and claiming that it is not an infringement of the patient's right to self-determination if we intervene. However, this often makes us uncomfortable, and if as a consequence we allow the patient to choose such a course of action, we can hardly define it as a sign of a mental illness.

If we accept that mind and body are two sides of a materialist, and hence deterministic, coin, then there can be no truly ‘free’ will, as any future event is deterministically caused by the past, and we have no control over that. Free will is incompatible with a materialist, monist position. Some authors have gone to considerable lengths to find a way out of this impasse. For instance, Hameroff and Penrose [7] have proposed that indeterminacy which can account for free will is introduced into a material deterministic system such as the brain by ‘quantum effects in cytoskeletal microtubules within neurones’. But we do not need to go as far as this to find a way out of the problem. Let us instead take a simpler, clinically-based perspective.

1.4 Clinical Implications

Let us consider a common clinical scenario of a teenage girl who has ‘never been a problem’ to her parents (by which it might be meant that she has not before asserted herself or easily engaged in conflict), has worked hard at school and achieved well, and has been compliant at home. She is likely to have been described as ‘sensitive’ in that she takes things to heart and can be quite easily hurt or upset by comments from friends. Not infrequently, her family has accommodated to her sensitivity by adapting to a life in which conflict is avoided, or in which, in order to avoid upset, her parents have become overly solicitous and protective.

Often, because of this previous experience of an ideal child, parents are deeply shocked and bewildered by what seems to be a very rapid change into someone they feel they hardly know. Compliance has been replaced by opposition, which at times is violent and extreme, although this may only occur in situations in which food is involved. Their sense of themselves as competent parents is under threat and they feel a bewildering range of emotions, including resentment, anger and frustration, about which they usually then feel guilty. What is the clinician to make of this?

Specialists in the field are now clear that what is disordered in ‘eating disorders’ is far more than attitudes to eating, food, weight and shape. But given their prominence, let us begin by considering the issue of food intake and energy balance.

1.5 Restriction of Energy Intake and Increase in Energy Output

From a clinical perspective, the restriction of energy intake manifests itself in a number of different ways. The patient is often preoccupied with ‘healthy eating’ (which in reality is very unhealthy, in that the amount of energy that her diet is providing is substantially less than that required to sustain normal life). She will often have a particular fear of, or revulsion towards, energy-dense foods, which in essence means foods that contain fat. Very often she will have a belief that any fat that is consumed immediately reappears as fat on her body. Even when all fat has been eliminated from her diet, she will continue to reduce the amount of food consumed until either she has reached zero intake or she has been admitted to hospital. To the clinician it is obvious that this fear of energy intake is very far removed from the popular idea of someone who is dieting or slimming in order to lose weight. It has all the features of a genuine phobia with the attendant intense and frequently overwhelming anxiety that makes it impossible for the patient to approach food voluntarily.

Along with the avoidance of energy intake, those suffering with AN are frequently dominated by an intense drive to expend energy. Again, the intensity of this drive is far removed from the activity of those who want to ‘get fit’ or to use exercise as a way of losing a little weight. The activity can take almost any form. If she has previously enjoyed sport, the patient will intensify the amount of time she spends in swimming, running, cycling or gymnastics. It is clear that the motivation is no longer that of enjoyment. The patient is driven by something that has long since ceased to be under her control, and which leaves her feeling unbearably guilty, bad and lazy. It is extremely difficult for her to sit down for anything other than the briefest periods; she will be found doing her homework standing up, eating standing up, listening to the radio or watching television standing up—in fact, doing anything standing up that can be done standing up. Even when she does sit down she will often hold her body in a tense position, or will jiggle her legs up and down ceaselessly.

Patients with AN behave as if their homeostatic systems, which normally should be seeking a balance between energy input and output, have become reset, so that any situation in which input equals or exceeds output provokes extreme anxiety. Normally, when output exceeds input, these homeostatic systems should trigger activation of responses that are accompanied by subjective experiences of hunger and the initiation of food-seeking and eating behaviour. In this situation the survival goal is restoration of energy balance, and any activity that moves the organism back towards that goal should produce a positive emotional state, whereas activity that results in moving further away from that goal should produce a negative emotional state.

For the patient with AN, something has happened that has reset the desired goal away from energy balance, so that her emotional state becomes more negative the nearer she moves towards energy balance. And once a severe negative energy balance occurs, neurotransmitter imbalance dramatically complicates the situation (see Chapter 5).

1.6 Non-Eating-Related Concerns

One of the advantages of working in an inpatient unit is that one spends a considerable amount of time in daily contact with patients in a way that is denied to those engaged exclusively in outpatient practice. This allows one to see even more clearly that their concerns are not just centred on food, weight and shape. Although there is no doubt that abnormal attitudes to energy intake and output (i.e. restricted food intake and increased activity) are central, patients with eating disorders invariably have serious difficulties with, amongst other things, perfectionism, rigidity, obsessionality, submissiveness, low self-esteem, sexuality and quite generalised difficulties with putting feelings into words (alexithymia).

One soon notices that patients not only deny themselves the comfort of food, but also the comfort of warmth, or of sitting on soft chairs. They find it very difficult to make eye contact, or to say ‘hello’ when greeted. Some may ‘fly off the handle’ for apparently obscure reasons. It is difficult for those who have not worked with patients with AN to comprehend their extreme sensitivity to the ways they respond to stimuli from the external world. It is as if the ‘gain’ on the input controls is turned up to maximum. Small changes in the external environment are experienced as ‘catastrophic’ and lead to massive reactions. If someone is only a minute or two late to an appointment it will be experienced as a major disaster and interpreted as evidence that the patient is not worth anything or that they are hated. A voice raised in mild irritation is experienced as a shout and a mild, relatively polite, justifiable criticism will be experienced as ‘character assassination’.

It is frequently noted that people with AN evidence a strong need to feel in control of their environment. They find it difficult to allow others to make decisions and can very easily become upset if someone disagrees with them. Parents may be accused of ‘not listening’ when actually what is meant is that the parents are not obeying their demands. They insist on life being arranged the way they want it and often find it extremely difficult to understand why this might present prob...

Table of contents

• Cover
• Title Page
• Copyright
• Dedication
• List of contributors
• Acknowledgements
• Preface
• Chapter 1: Why Clinicians Should Love Neuroscience: the Clinical Relevance of Contemporary Knowledge
• Chapter 2: Eating Disorders: an Overview
• Chapter 3: Neuroimaging
• Chapter 4: Neuropsychology
• Chapter 5: Neurochemistry: the Fabric of Life and the Fabric of Eating Disorders
• Chapter 6: Body-Image Disturbance
• Chapter 7: Conceptual Models
• Chapter 8: Towards a Comprehensive, Causal and Explanatory Neuroscience Model of Anorexia Nervosa
• Chapter 9: Neurobiological Models: Implications for Patients and Families
• Chapter 10: Implications for Treatment
• Chapter 11: Future Directions
• Index
• Color Plates