Eating Disorders (PDF)

 i Eating Disorders  ii  1 iii Eating Disorders S E CO N D E D I T I O N Pamela K. Keel  1 iv Oxford University Press is a department of the University of Oxford. It furthers the University’s objective of excellence in research, scholarship, and education by publishing worldwide. Oxford is a registered trade mark of Oxford University Press in the UK and certain other countries. Published in the United States of America by Oxford University Press 198 Madison Avenue, New York, NY 10016, United States of America. © Oxford University Press 2017 This book was previously published by: Pearson Education, Inc. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, without the prior permission in writing of Oxford University Press, or as expressly permitted by law, by license, or under terms agreed with the appropriate reproduction rights organization. Inquiries concerning reproduction outside the scope of the above should be sent to the Rights Department, Oxford University Press, at the address above. You must not circulate this work in any other form and you must impose this same condition on any acquirer. Library of Congress Cataloging- in- Publication Data Names: Keel, Pamela K., 1970– Title: Eating disorders / Pamela K. Keel. Description: Second edition. | Oxford : Oxford University Press, [2017] | Includes bibliographical references and index. Identifiers: LCCN 2016011938 (print) | LCCN 2016014569 (ebook) | ISBN 9780190247348 | ISBN 9780190247355 (ebook) Subjects: LCSH: Eating disorders. Classification: LCC RC552.E18 K44 2017 (print) | LCC RC552.E18 (ebook) | DDC 616.85/26—dc23 LC record available at http://lccn.loc.gov/2016011938 9 8 7 6 5 4 3 2 1 Printed by WebCom, Inc., Canada  v Contents Preface ix Acknowledgments xiii 1. Introduction: What Are Eating Disorders? 1 Anorexia Nervosa 2 Bulimia Nervosa 5 Binge-Eating Disorder 7 Other Specified Feeding or Eating Disorder 8 Unspecified Feeding or Eating Disorder 11 Eating Disorders as a Continuum of Problems 12 Conclusion 14 2. Related Conditions That Are Not Eating Disorders 16 Pica 17 Rumination Disorder 18 Avoidant/Restrictive Food Intake Disorder 19 Obesity 21 Conclusion 25 3. Who Suffers From Eating Disorders? 27 Who Suffers in Treatment Samples 27 Who Suffers in Community-Based Samples 28 Eating Disorders and Men 29 Eating Disorders and Race/Ethnicity 32 Eating Disorders in Non-Western Cultures 37 History of Eating Disorders 40  vi | Co n t e n t s vi Modern Trends in Incidence and Prevalence of Eating Disorders 50 Conclusion 52 4. Finding the Causes of Eating Disorders: Going Beyond Descriptive Methods 54 Hypotheses 54 Longitudinal Studies 55 Experimental Studies 62 Naturalistic Investigations 66 Conclusion 67 5. Body Image, Dieting, and Eating Disorders: Can We Blame the Media? 69 The Cultural Ideal of Thinness 70 Why Does Thin = Good? 72 Societal Denigration of Overweight and Obesity 75 Body Image 79 Dieting 81 Conclusion 83 6. Family and Peer Factors in the Development of Eating Pathology 85 Psychoanalytic Model of Family Influence 85 Psychodynamic Model of Family Influence 87 Family Systems Model of Family Influence 90 Social Learning Model of Family Influence 92 Influence of Parental Modeling Versus Parental Direct Comments 94 Peer Influences on Eating Pathology 95 Conclusion 100 7. Psychological Factors in the Development of Eating Disorders: The Contributions of Personality and Cognitive- Affective Processes 101 Personality 101 Cognitive and Affective Processes 106 Conclusion 117 8. Biological Bases, Correlates, and Consequences of Eating Disorders 119 Brain Function and Eating Disorders 120 Genetic Contributions to Eating Disorders 131 Physical Consequences of Eating Disorders 139 Conclusion 143 9. Treatment 146 Treatment Use 146  Co n t e n t s | vii vii Treatment Modalities 148 Psychotherapy Content and Theoretical Orientations 153 Nonpsychotherapy Interventions 165 Conclusion 168 10. Prevention 170 Prevention Paradigms 170 Prevention Themes and Content 172 Implementing Prevention and Levels of Intervention 172 Conclusion 179 11. Long- Term Course and Outcome 182 Anorexia Nervosa 182 Bulimia Nervosa 186 Binge- Eating Disorder 190 Purging Disorder 191 Comparison of DSM- 5 Eating Disorders 193 Conclusion 195 12. Conclusion 196 Case Studies Revisited 196 Current Knowledge and Ongoing Debates 201 Future Directions 209 Glossary 211 References 219 Additional Resources 251 About the Author 253 Index 255  viii  ix Preface I wrote the first edition of Eating Disorders to address a problem I encountered while teach- ing an undergraduate course on this topic. After using a sourcebook of peer- reviewed jour- nal articles for two years, I realized that before progressing to the primary literature, my students needed a text that summarized and synthesized the research base. The problem was that no such text existed. My solution was to write the book I needed and hope that it would be helpful to other instructors and students facing the same problem. This means that I am both the author of this book and an instructor who has used it in my courses. As time passed, I became increasingly (and at times uncomfortably) aware of the gap between what the first edition covered and what was now known about eating disorders. Initially this gap gave me an opportunity to present new and exciting findings in my lectures to supplement the reading. However, as more time passed and the gap grew wider, I knew that the only way to effectively teach my students was to write a second edition. Since the publication of the first edition of this book in 2005, many new and important findings have emerged in the field. A new edition of the Diagnostic and Statistical Manual of Mental Disorders was published, altering the definitions of existing eating disorders and including new eating disorders. Indeed, my own program of research has focused heavily on defining and characterizing the new syndrome of purging disorder— a condition that was not even mentioned in this book’s first edition! To reflect these and other advances in the field, information on purging disorder and night eating syndrome has been added to the second edition along with new case studies for each, and a new chapter has been included to address the related conditions of feeding disorders and obesity. The book has also been updated with new findings on the epidemiology of eating disorders to reflect the replication of the National Comorbidity Survey and several epidemiological studies focusing on eating disorders in racial and ethnic minority groups. Other changes include an increased focus on eating pathology in boys and men, more discussion of the influence of peers and social media on eating disorder risk, and descriptions of new findings from neuroimaging studies. One of the most exciting aspects of working on the second edition was the opportunity to  x | P r e faCe x review new studies of prevention programs that reduce risk for the onset of eating disorders, as these studies have fundamentally altered conclusions regarding the success of prevention efforts in the field. While the coverage of information on eating disorders has been fully updated for the second edition, the topic of eating disorders remains compelling for the same reasons as presented in the first edition. Eating disorders provide a perfect opportunity to examine the intersections of culture, mind, and body. To truly appreciate the causes and consequences of these disorders, one must be willing to consider topics that span the humanities (history, art, and literature), the social sciences (psychology, anthropology, women’s studies, and econom- ics), and the natural sciences (anatomy, physiology, pharmacology, and genetics). As a conse- quence, there is truly something for everyone in the study of eating disorders. Few topics of inquiry allow individuals from so many disciplines to make significant contributions. Eating disorders are all around us. Almost anyone who picks up this book knows someone who has suffered from an eating disorder. Unlike numerous other topics in aca- demia, eating disorders are often part of our personal lives. Even individuals who are for- tunate enough to have never had an eating disorder or watched a loved one suffer from an eating disorder probably know someone who has. Eating disorders are very topical. Many famous individuals have acknowledged the impact of these disorders on their lives. Thus even people who have not personally known someone with an eating disorder have a sense of familiarity with the problem. This topicality has two consequences. First, people probably know more about eating disorders than about many other subjects that might be covered by a textbook. Second, they probably have far more misinformation about eating disorders than they do about other textbook topics. Thus eating disorders can be both familiar and challenging (rather than more common combina- tions of familiar and boring or challenging and intimidating). The field of eating disorders is still young. Sections of this book were difficult to write because there remains much that we simply do not know about these disorders. However, this limitation also represents an opportunity. Because there is so much left to learn, there are many ways that people can make a significant contribution to the knowledge base of these disorders. Young people have completed many fascinating and illuminating studies in the eating disorders field. This book includes many studies conducted by college under- graduates because of the important conclusions that can be drawn from them. Case Studies Like most textbooks on psychopathology, this one uses case studies to help bring its subject matter to life. Case studies are particularly important for illustrating eating disorders, since these disorders never exist in a vacuum but rather occur in the context of an individual’s life. To balance the competing demands of breadth and depth, five case studies are followed throughout the book. Instead of presenting 25 different cases briefly, the book integrates the topics of different chapters into the lives of these five individuals, providing further in- sight into each one. For this reason, it is best if the chapters are covered in order. Reading Chapter 1 first would be worthwhile even for individuals who are intimately familiar with  P r e faCe | xi xi the definitions of eating disorders, because that is where I introduce the cases that guide the reader throughout the text. Similarly, even if the time constraints that are present in any course mean that the final chapters are not part of the assigned reading, it is still worth reading them to learn more about how things turn out for the individuals introduced in Chapter 1. Features for Students Terms that may be new to students are defined within chapters and are included in a glos- sary at the end of the book. Glossary terms are presented in boldface type in the text and are listed at the end of the first chapter in which they play a key role. Italic type is used for other key terms to draw students’ attention to important topics within chapters. Tables and figures are also included as study aids. While figures reinforce the information described in the text, tables often provide additional information. Thus figures are illustrative, and tables provide concise reviews of information often not presented elsewhere in the book. Each chapter includes a brief conclusion. The conclusion is not intended to serve as an abstract for the full chapter. Instead, it provides empirically supported take-home points regarding the topic of the chapter (when such conclusions are possible). This book includes a chapter devoted to research methodology (Chapter 4), with ex- amples from studies of eating disorders. This chapter is designed to enable students who have not completed prior coursework on research methods to critically evaluate the strengths and weaknesses of conclusions drawn from the empirical literature. The chapter also may serve as a refresher for students in advanced psychology courses who have already completed coursework on research methods.  xii  xiii Acknowledgments I want to start by thanking the instructors and students who used the first edition of Eating Disorders. Writing is an important form of communication only when someone reads what you have written. Without those readers, there would be no second edition. I want to thank the reviewers of the chapter drafts, who provided exceptionally helpful feedback regarding opportunities to improve coverage of this growing field so that the book remains useful for a broad audience. I also want to thank the students who have taken my eating disorders class, because they have provided valuable feedback (both positive and negative) about as- pects of the first edition which were most and least effective for their learning. Comparison of the first and second editions will reveal a dramatic decline in the number of detailed tables: Students talked, and I listened. I am deeply indebted to the efforts of many members of the Oxford University Press staff, including Sarah Harrington and Andrea Zekus. Finally, I want to thank you for your interest in this topic. Pamela K. Keel  xiv