The eating disorders (such as anorexia nervosa and bulimia) and obesity, have become major public health problems throughout the developed world. And, they are beginning to cause concern in the developing world. It was not always thus. Anorexia nervosa was something of a clinical curiosity until the 20th century and was relatively uncommon until after World War II. Bulimia nervosa was not formally described before 1979. Obesity, which at one time was considered the mark of the successful man, is now recognized to be a serious health hazard. It has reached epidemic proportions, consuming an ever larger proportion of the health resources of many countries.

It is customary in current medical practice, as well as in formal nosological systems, [such as the Diagnostic and Statistical Manual of the American Psychiatric Association, 4th edition (DSM-IV) and the International Classification of Disease (ICD 10)], to distinguish between ‘eating disorders’ (which are viewed primarily as disorders of behavior), and disorders of body weight, such as obesity. The eating disorders are categorized as mental illnesses, and as such, are the province of psychiatrists and allied mental health workers. Obesity, on the other hand, which is seen primarily as a physical condition, is more the concern of specialists in internal medicine. However, a moment's reflection will reveal that such a separation is both arbitrary and unjustified. Obesity arises from behaviors which are physiologically inappropriate (such as consuming food when there is no metabolic need); conversely eating disorders can cause profound alterations in physiology and body composition. Furthermore, many of the drugs used in the treatment of eating disorders, such as the newer ‘atypical antipsychotics’, frequently cause obesity, and some appetite suppressants prescribed for obesity, can cause marked changes in mood and behavior. Thus, the distinction between the two groups of conditions is not as clear-cut as DSM-IV and ICD-10 make it appear. Most patients who develop one of the eating disorders are extremely frightened of gaining weight. The disordered eating can be viewed as a pathological reaction to this fear and a distorted attempt to establish control of body weight.

This book, as its title implies, focuses on the place of drugs in the treatment of both sets of illnesses – the eating disorders and obesity. It is arranged in two parts: Part I addresses the science of eating behavior. It examines the physiology, psychology and pharmacology of normal eating, addressing two fundamental questions: ‘why do we eat?’ and ‘why, having started eating, what makes us stop?’ Part II is clinically oriented. It covers each of the recognized eating disorders, and obesity. Each of its constituent chapters reviews the clinical features, the epidemiology and pathophysiology of the particular disorder being covered, before going on to discuss the available treatment options with particular reference to drugs. The last two chapters deal with disorders of eating and body weight at the two ends of the life cycle: childhood and adolescence at one end; old age at the other.

In our society, the homily that “Cleanliness is next to godliness” has given way, as Hilde Bruch so pithily expressed it, to: “Slenderness is next to godliness”. That this is indeed the case, is exemplified by icons of American beauty such as beauty pageant contestants and Playboy centerfolds, who have become progressively thinner and thinner over the past 50 years. Similar standards of what constitutes the desirable female figure have now spread throughout the developed world and are percolating through the developing world as well. This concern with being too fat is what typically lies behind the onset and continuance of the specific eating disorders such as anorexia nervosa and bulimia nervosa.

The eating disorders are serious maladies which can give rise to a host of debilitating physical and psychological consequences. It is estimated that the global burden of disease for which these illnesses are responsible in women, is higher than that due to schizophrenia or bipolar affective disorder. Obesity is of even greater concern. It is associated with a whole range of serious, life-threatening medical conditions such as diabetes, hypertension and coronary heart disease, and significantly prejudices longevity. Obesity-related conditions contribute to several hundred thousand deaths a year in the United States alone.

This book was written to help all the many health professionals, and their patients, who are wrestling with the myriad physical and psychological problems caused by eating disorders and obesity. I trust that it will also inform policy makers and public health planners.

I wish to express my thanks to Dr. Janet Polivy, Dr. Peter Herman and Dr. Patty Pliner of the feeding research group in the Department of Psychology in the University of Toronto for including me in their weekly seminars. These provided a stimulating collegial environment which helped me greatly during the course of writing this book. I would also like to thank Peter Brown, of IOS Press for his continuing commitment to this project, and for his stalwart support throughout. Finally, I wish to express gratitude to my wife, Sarah Romans, a fellow health professional, for the unstinting assistance she has given me throughout this book's gestation.

Trevor Silverstone

Toronto, May 2005