16.1 Introduction
This chapter discusses eating disorders. In the current psychiatric nomenclature of DSM-IV-TR the eating disorders consist of two clearly defined syndromes, anorexia nervosa and bulimia nervosa, but many individuals presenting for treatment of an eating disorder fail to meet the formal criteria for either. It is likely that eating disorders are more heterogeneous than the DSM indicates and the categories may be too restrictive. A broader approach is to think of an eating disorder as a persistent disturbance of eating behavior intended to control weight that impairs psychological functioning and/or physical health.
The DSM-IV-TR criteria for anorexia nervosa (AN) require the individual to be significantly underweight for age and height. Although it is not possible to set a single weight-loss standard that applies to all individuals, DSM-IV-TR provides a guideline of 85% of the weight considered normal for age and height. Despite being of an abnormally low body weight, individuals with anorexia nervosa are intensely afraid of gaining weight and becoming fat, and this fear typically intensifies as the weight falls.
DSM-IV-TR criterion C requires a disturbance in the person’s judgment about his or her weight or shape. Despite being underweight, individuals with anorexia nervosa often view themselves or a part of their body as being too heavy. Typically, they deny the grave medical risks engendered by their semi-starvation and place enormous psychological importance on whether they have gained or lost weight. Patients with anorexia nervosa may feel intensely distressed if their weight increases by half a pound. Criterion D of DSM-IV-TR additionally requires that women with anorexia nervosa be amenorrheic.
Although the criteria seem relatively straightforward, the greatest problem in the assessment of patients with anorexia nervosa is their denial of the illness and their reluctance to participate in an evaluation. A straightforward but supportive and non-confrontational style is probably the most useful approach to making a diagnosis and treatment, but it is likely that the patient will not acknowledge significant difficulties in eating or with weight and will rationalize unusual eating or exercise habits. It is therefore helpful to obtain information from other sources, such as the patient’s family.
There are two types of anorexia nervosa:
- Restricting type: The person restricts food intake and does not engage in binge-eating or purging behavior.
- Binge eating/purging type: The person self-induces vomiting or misuses laxatives, diuretics, or enemas.
16.2.1 Physiological Disturbances
An impressive array of physical disturbances has been documented in anorexia nervosa (Table 16.1). Most of these appear to be secondary consequences of starvation, and it is not clear whether or how the physiological disturbances listed contribute to the development and maintenance of the psychological and behavioral abnormalities characteristic of the illness.
Table 16.1 Medical problems associated with anorexia nervosa.
| Skin | Lanugo |
| Cardiovascular | Hypotension |
| Bradycardia | |
| Arrhythmias | |
| Hemopoietic system | Normochromic normocytic anemia |
| Leukopenia | |
| Fluid and electrolyte balance | Elevated urea nitrogen and creatinine |
| Hypokalemia | |
| Hyponatremia | |
| Hypochloremia | |
| Alkalosis | |
| Gastrointestinal system | Elevated liver enzymes |
| Delayed gastric emptying | |
| Constipation | |
| Endocrine system | Diminished thyroxine level with normal thyroid stimulating hormone level |
| Elevated plasma cortisol | |
| Diminished secretion of luteinizing hormone, follicle stimulating hormone, estrogen, or testosterone | |
| Bone | Osteoporosis |
Common laboratory findings are a mild-to-moderate normochromic, normocytic anemia and leukopenia, with a deficit in polymorphonuclear leukocytes leading to a relative lymphocytosis. Elevations of blood urea nitrogen and serum creatinine concentrations may occur because of dehydration, which can also artificially elevate the hemoglobin and hematocrit. A variety of electrolyte abnormalities may be observed, reflecting the state of hydration and the history of vomiting and diuretic and laxative abuse. Serum levels of liver enzymes are usually normal but may transiently increase during refeeding.
Cholesterol levels may be elevated. The electrocardiogram typically shows sinus bradycardia and, occasionally, low QRS voltage and a prolonged QT interval. A variety of arrhythmias have also been described in the literature.
16.2.2 Epidemiology
Anorexia nervosa is a relatively rare illness. The point prevalence of strictly defined AN is only about 0.5%. The prevalence rates of partial syndromes (those not meeting the complete criteria) are substantially higher. Some studies suggest that its incidence has increased significantly during the last 50 years, and that the increase is due to changes in cultural norms regarding desirable body shape and weight. Anorexia nervosa mostly affects women, the ratio of men to women being between 1 : 10 and 1 : 20. It occurs primarily in industrialized and affluent countries, with data suggesting that the condition is more common among the higher socioeconomic classes. Some occupations, such as ballet dancing and fashion modeling, appear to confer a particularly high risk for the development of anorexia nervosa.
16.2.3 Course
The course of the illness is fairly typical across cases. An adolescent girl or young woman who is of normal weight or, perhaps, a few pounds overweight decides to diet. This decision may be prompted by an important but not extraordinary life event, such as attending a new school. Initially the dieting seems moderate but it intensifies as weight falls. Dietary restrictions become broader and more rigid. The person begins to avoid meals with others. The individual has idiosyncratic rules about eating and exercise. Food avoidance and weight loss are accompanied by a sense of accomplishment, and weight gain is viewed as a failure and a sign of weakness. Physical activity, such as running or aerobic exercise, often increases as the dieting and weight loss develop. Inactivity and complaints of weakness usually occur only when emaciation has become extreme. The person’s life becomes centered around food and exercise. The person may become depressed and emotionally labile, withdrawn and secretive. She or he may lie about weight and eating behavior. Despite the profound disturbances in the way the person views her or his weight and calorie needs, reality testing is otherwise intact, and the person may continue to function well in school or at work. Symptoms usually persist for months or years until, typically at the insistence of friends or family, the person reluctantly agrees to see a professional. When the illness occurs in males the course is very similar to that in females.
Patients with this illness exhibit significant impairment in their lives as a result of their eating rituals and chronic states of semi-starvation. There is also an associated mortality. Data suggest that 10–20% of patients who have been hospitalized for AN will, in the next 10–30 years, die as a result of their illness. Much of the mortality is due to severe and chronic starvation, which eventually terminates in sudden death. A significant proportion of patients commit suicide.
16.2.4 Etiology
Anorexia nervosa occurs most frequently in biological relatives of patients who present with the disorder. However, conclusive data for genetic transmission of the disorder are not yet available.
Because anorexia nervosa typically begins during adolescence, developmental issues are thought to play an important etiological role. These include the critical challenges of establishing independence, defining a personal identity, family struggles, and conflicts regarding sexuality. However, it is not clear that difficulties over these issues are more salient for individuals who will develop anorexia nervosa than for other adolescents.
Family traits, such as over-protective mothers and passive fathers, have been identified in the literature as typical of parents of suffers. But few empirical studies have been conducted to date, particularly studies that also examine psychiatrically or medically ill comparison groups. Hence, despite theorizing, the precise role of the family in the development and course of anorexia nervosa has not been clearly delineated.
Cognitive–behavioral theories emphasize the distortions and dysfunctional thoughts (e.g., dichotomous thinking) that may stem from various causal factors, all of which eventually focus on the belief that it is essential to be thin. Certain personality traits have commonly been reported among women with the illness. These include high degrees of self-discipline, conscientiousness, and emotional caution. Depression has been implicated as a nonspecific risk factor.
Social psychologists suggest that an increased prevalence of anorexia nervosa is related to the emphasis in contemporary Western society on an unrealistically thin appearance in women which has increased significantly during the past several decades. Other authors have noted that the core features of the illness have been described in other cultural settings, indicating that the current societal emphasis on thinness is not a necessary precondition for the development of this syndrome.
16.2.5 Differential Diagnosis
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