Anorexia Nervosa

Anorexia Nervosa

Definition

The DSM-IV-TR criteria 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 equally to all individu-als, DSM-IV-TR provides a benchmark of 85% of the weight con-sidered normal for age and height as a guideline. Despite being of an abnormally low body weight, individuals with anorexia ner-vosa are intensely afraid of gaining weight and becoming fat, and remarkably, this fear typically intensifies as the weight falls.

DSM-IV-TR criterion C requires a disturbance in the per-son’s judgment about his or her weight or shape. For example, 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 semistarvation and place enormous psychological importance on whether they have gained or lost weight. For example, some-one with anorexia nervosa may feel intensely distressed if her or his weight increases by half a pound. Finally, criterion D requires that women with anorexia nervosa be amenorrheic.

The DSM-IV-TR criteria for anorexia nervosa are gener-ally consistent with recent definitions and descriptions of this ill-ness. In addition, in DSM-IV-TR, a new subtyping scheme was introduced. DSM-IV-TR suggests that individuals with anorexia nervosa be classed as having one of two variants, either the binge-eating/purging type or the restricting type. Individuals with the re-stricting type of anorexia nervosa do not engage regularly in either binge-eating or purging and, compared with individuals with the binge-eating/purging form of the disorder, are not as likely to abuse alcohol and other drugs, exhibit less mood lability and are less ac-tive sexually. There are also indications that the two subtypes may differ in their response to pharmacological intervention.

Epidemiology

Anorexia nervosa is a relatively rare illness. Even among high-risk groups, such as adolescent girls and young women, the preva-lence of strictly defined anorexia nervosa is only about 0.5%. The prevalence rates of partial syndromes are substantially higher. Despite the infrequent occurrence of anorexia nervosa, most studies suggest that its incidence has increased significantly dur-ing the last 50 years, a phenomenon usually attributed to changes in cultural norms regarding desirable body shape and weight Anorexia nervosa usually affects women; the ratio of men to women is approximately 1 : 10 to 1 : 20. Anorexia nervosa oc-curs primarily in industrialized and affluent countries and some data suggest that even within those countries, anorexia nervosa 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. Thus, anorexia nervosa appears more likely to develop in an environment in which food is readily available but in which, for women, being thin is somehow equated with higher or special achievement.

Etiology

At present, the etiology of anorexia nervosa is fundamentally unknown. However, from several sources, such as the epidemio-logical data just reviewed, it is possible to identify risk factors whose presence increases the likelihood of anorexia nervosa. It is also possible to describe the course and complications of the syndrome and to suggest interactions between features of the dis-order, for example, between malnutrition and psychiatric illness. Thus, as indicated in Figure 58.2, the difficulties that lead to the development of anorexia nervosa may be distinct from the forces that intensify the symptoms and perpetuate the illness once it has begun.

Genetic and Twin Studies

Anorexia nervosa occurs more frequently in biological relatives of patients who present with the disorder. The prevalence rate of anorexia nervosa among sisters of patients is estimated to be approximately 6%; the morbid risk among other relatives ranges from 2 to 4%. Some evidence for a genetic component in the etiol-ogy of anorexia nervosa comes from twin studies, which reported substantially higher concordance rates for monozygotic than for dizygotic twin pairs (Klump et al., 2001). However, conclusive data for genetic transmission of the disorder are not yet available

Family Studies

Individual psychiatric disorders in parents, dysfunctional fam-ily relationships and impaired family interaction patterns have been implicated in the etiology of anorexia nervosa. Mothers of individuals with anorexia nervosa are often described as over-protective, intrusive, perfectionistic and fearful of separation; fathers are described as withdrawn, passive, emotionally con-stricted, obsessional, moody and ineffectual. Family systems theorists have suggested that impaired family interactions such as pathological enmeshment, rigidity, overprotectiveness, and difficulties confronting and resolving conflicts are central fea-tures of anorexic pathology. However, few empirical studies have been conducted to date, particularly studies that also examine psychiatrically or medically ill comparison groups. Therefore, the precise role of the family in the development and course of anorexia nervosa, although undoubtedly important, has not been clearly delineated.

Psychosocial Factors

The increased prevalence of anorexia nervosa has been connected to the current emphasis in contemporary Western society on an unrealistically thin appearance in women. There is substantial evidence that a desire to be slim is common among middle- and upper-class white women and that this emphasis on slimness has increased significantly during the past several decades. In the USA, anorexia nervosa develops much more frequently in white adolescents than in adolescents from other racial groups. It has been suggested that a variety of characteristics may protect African-American girls from having eating disorders, including more acceptance of being overweight, more satisfaction with their body image and less social pressure regarding weight.

It has also been suggested that the emphasis of contem-porary Western society on achievement and performance in women, which is a shift from the more traditional emphasis on deference, compliance and unassertiveness, has left many young women vulnerable to the development of eating disorders such as anorexia nervosa. These multiple and contradictory role demands are embodied within the modern concept of a superwoman who performs all of the expected roles (e.g., is competent, ambitious and achieving, yet also feminine, nurturing and sexual) and, in addition, devotes considerable attention to her appearance (Gordon, 1990).

Psychodynamic Factors

Various psychoanalytic theories have been postulated (e.g., de-fense against fantasies of oral impregnation; underlying deficits in the development of object relations; deficits in self-structure), but such hypotheses are difficult to verify. Bruch (1973, 1982) suggested that anorexia nervosa stems from failures in early at-tachment, attempts to cope with underlying feelings of ineffec-tiveness and inadequacy, and an inability to meet the demands of adolescence and young adulthood. These ideas, as well as her conceptualization that the single-minded focus on losing weight in anorexia nervosa is the concrete manifestation of a struggle to achieve a sense of identity, purpose, specialness and control, are compelling and clinically useful. Cognitive–behavioral theo-ries emphasize the distortions and dysfunctional thoughts (e.g., dichotomous thinking) that may stem from various causal fac-tors, all of which eventually focus on the belief that it is essential to be thin.

Although the existence of a specific predisposing person-ality style has not been conclusively documented, certain traits have commonly been reported among women with anorexia nervosa. Women hospitalized for anorexia nervosa have greater self-discipline, conscientiousness and emotional caution than women hospitalized for bulimia nervosa and women with no eat-ing disorders. In addition, even after they have recovered from their illness, women who have had anorexia nervosa tend to avoid risks and to exhibit high levels of caution in emotional expression and strong compliance with rules and moral standards.

Developmental Factors

Because anorexia nervosa typically begins during adolescence, developmental issues are thought to play an important etiologi-cal role. Critical challenges at this time of life include the need to establish independence, a well-defined personal identity, ful-filling relationships, and clear values and principles to govern one’s life. Family struggles, conflicts regarding sexuality and pressures regarding increased heterosexual contact are also com-mon. However, it is not clear that difficulties over these issues are more salient for individuals who will develop anorexia nervosa than for other adolescents. Depression has been implicated as a nonspecific risk factor, and higher levels of depressive symptoms as well as insecurity, anxiety and self-consciousness have been documented in adolescent girls in comparison with adolescent boys. Similarly, the progression of physical and sexual matura-tion and the concomitant increase in women’s percentage of body fat may have a substantial impact on the self-image of adolescent girls, particularly because the relationship between self-esteem and satisfaction with physical appearance and body characteris-tics is stronger in women than in men.

Pathophysiology

An impressive array of physical disturbances has been docu-mented in anorexia nervosa and the physiological bases of many are understood (Table 58.1). Most of these physical disturbances appear to be secondary consequences of starvation, and it is not clear whether or how the physiological disturbances described here contribute to the development and maintenance of the psy-chological and behavioral abnormalities characteristic of ano-rexia nervosa. The remainder of this section briefly describes the major physical abnormalities of anorexia nervosa and what is understood about their etiology.

The central nervous system is clearly affected. Computed tomography has demonstrated that individuals with anorexia ner-vosa have enlarged ventricles, an abnormality that improves with weight gain. The cerebrospinal fluid concentrations of a variety of neurotransmitters and their metabolites are altered in under-weight patients with anorexia nervosa and tend to normalize as weight is restored. An intriguing exception may be the serotonin metabolite 5-hydroxyindoleacetic acid, which has been reported to be elevated in the cerebrospinal fluid of patients with anorexia nervosa after they have achieved a normal or near-normal weight. Kaye (1997) has suggested that the elevated 5-hydroxyindoleace-tic acid levels may reflect a serotoninergic abnormality that is tied to the obsessional traits often observed in anorexia nervosa.

Some of the most striking physiological alterations in ano-rexia nervosa are those of the hypothalamic–pituitary–gonadal axis. In women, estrogen secretion from the ovaries is markedly reduced, accounting for the occurrence of amenorrhea. In analo-gous fashion, testosterone production is diminished in men with anorexia nervosa. The decrease in gonadal steroid production is due to a reduction in the pituitary’s secretion of the gonadotropins luteinizing hormone and follicle-stimulating hormone, which in turn is secondary to diminished release of gonadotropin-releasing

hormone from the hypothalamus. Therefore, the amenorrhea of anorexia nervosa is properly viewed as a type of hypothalamic amenorrhea. It is of interest that in a significant minority amenor-rhea begins before substantial weight loss has occurred, suggest-ing that factors other than malnutrition, such as psychological distress, contribute significantly to the disruption of the repro-ductive endocrine system.

In an adult with anorexia nervosa, the status of the hy-pothalamic–pituitary–gonadal axis resembles that of a pubertal or prepubertal child – the secretion of estrogen or testosterone, of luteinizing hormone and follicle-stimulating hormone and of go-nadotropin-releasing hormone is reduced. This endocrinological picture may be contrasted with that of postmenopausal women who have a similar reduction in estrogen secretion but who, un-like women with anorexia nervosa, show increased pituitary go-nadotropin secretion. Furthermore, even the circadian patterns of luteinizing hormone and follicle-stimulating hormone secretion in adult women with anorexia nervosa closely resemble the pat-terns normally seen in pubertal and prepubertal girls. Although similar abnormalities are also seen in other forms of hypotha-lamic amenorrhea and are therefore not specific to anorexia ner-vosa, it is nonetheless striking that this syndrome is accompanied by a physiological arrest or regression of the reproductive endo-crine system.

The functioning of other hormonal systems is also disrupted in anorexia nervosa, although typically not as profoundly as is the reproductive axis. Presumably as part of the metabolic response to semistarvation, the activity of the thyroid gland is reduced Plasma thyroxine levels are somewhat diminished, but the plasma level of the pituitary hormone and thyroid-stimulating hormone is not elevated. The activity of the hypothalamic–pituitary–adrenal axis is increased, as indicated by elevated plasma levels of cortisol and by resistance to dexamethasone suppression. The regulation of vasopressin (antidiuretic hormone) secretion from the posterior pituitary is disturbed, contributing to the development of partial diabetes insipidus in some individuals.

Anorexia nervosa is often associated with the develop-ment of leukopenia and of a normochromic, normocytic anemia of mild to moderate severity. Surprisingly, leukopenia does not appear to result in a high vulnerability to infectious illnesses. Se-rum levels of liver enzymes are sometimes elevated, particularly during the early phases of refeeding, but the synthetic function of the liver is rarely seriously impaired so that the serum albu-min concentration and the prothrombin time are usually within normal limits. Serum cholesterol levels are sometimes elevated in anorexia nervosa, although the basis of this abnormality re-mains obscure. In some patients, self-imposed fluid restriction and excessive exercise produce dehydration and elevations of se-rum creatinine and blood urea nitrogen. In others, water loading may lead to hyponatremia. The status of serum electrolytes is a reflection of the individual’s salt and water intake and the nature and the severity of the purging behavior. A common pattern is hypokalemia, hypochloremia and mild alkalosis resulting from frequent and persistent self-induced vomiting.

It has become clear that individuals with anorexia ner-vosa have decreased bone density compared with age- and sex-matched peers and, as a result, are at increased risk for fractures. Low levels of estrogen, high levels of cortisol and poor nutrition have been cited as risk factors for the development of reduced bone density in anorexia nervosa. Theoretically, estrogen treat-ment might reduce the risk of osteoporosis in women who are chronically amenorrheic because of anorexia nervosa, but con-trolled studies indicate that this intervention is of limited, if any, benefit.

Abnormalities of cardiac function include bradycardia and hypotension, which are rarely symptomatic. The pump function of the heart is compromised, and congestive heart failure occa-sionally develops in individuals during overly rapid refeeding. The electrocardiogram shows sinus bradycardia and a number of nonspecific abnormalities. Arrhythmias may develop, often in association with fluid and electrolyte disturbances. It has been suggested that significant prolongation of the QT interval may be a harbinger of life-threatening arrhythmias in some individ-uals with anorexia nervosa, but this has not been conclusively demonstrated.

The motility of the gastrointestinal tract is diminished, leading to delayed gastric emptying and contributing to com-plaints of bloating and constipation. Rare cases of acute gastric dilatation or gastric rupture, which is often fatal, have been re-ported in individuals with anorexia nervosa who consumed large amounts of food when binge-eating.

As already noted, virtually all of the physiological abnor-malities described in individuals with anorexia nervosa are also seen in other forms of starvation, and most improve or disappear as weight returns to normal. Therefore, weight restoration is essen-tial for physiological recovery. More surprisingly, perhaps, weight restoration is believed to be essential for psychological recovery as well. Accounts of human starvation amply document the pro-found impact of starvation on mental health. Starving individuals lose their sense of humor, their interest in friends and family fadesand mood generally becomes depressed. They may develop pe-culiar behavior similar to that of patients with anorexia nervosa, such as hoarding food or concocting bizarre food combinations. If starvation disrupts psychological and behavioral functioning in normal individuals, it presumably does so as well in those with anorexia nervosa. Thus, correction of starvation is a prerequisite for the restoration of both physical and psychological health.

Diagnosis and Differential Diagnosis

Phenomenology

Anorexia nervosa often begins innocently. Typically, an adoles-cent 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 leaving home for camp, attending a new school, or a casual unflattering remark by a friend or family member. Initially, the dieting seems no different from that pursued by many young women, but as weight falls, the dieting intensifies. The restric-tions become broader and more rigid; for example, desserts may first be eliminated, then meat, then any food that is thought to contain fat. The person becomes increasingly uncomfortable if she is seen eating and avoids meals with others. Food seems to assume a moral quality so that vegetables are viewed as “good” and anything with fat is “bad”. The individual has idiosyncratic rules about how much exercise she must do and when, where and how she can eat.

Food avoidance and weight loss are accompanied by a deep and reassuring 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 becomes more serious and devotes little effort to anything but work, dieting and exercise. She may become depressed and emotionally labile, socially withdrawn and secretive and she may lie about her eating and her weight. Despite the profound distur-bances in her view of her weight and of her calorie needs, reality testing in other spheres is 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 physician.

In general, anorexia nervosa is not difficult to recognize. Uncertainty surrounding the diagnosis sometimes occurs in young adolescents, who may not clearly describe a drive for thin-ness and the fear of becoming fat. Rather, they may acknowl-edge only a vague concern about consuming certain foods and an intense desire to exercise. It can also be difficult to elicit the distorted view of shape and weight (criterion C) from patients who have had anorexia nervosa for many years. Such individu-als may state that they realize they are too thin and may make superficial efforts to gain weight, but they do not seem particu-larly concerned about the physical risks or deeply committed to increasing their calorie consumption.

Assessment

Special Issues in Psychiatric Examination and History

In assessing individuals who may have anorexia nervosa, it is important to obtain a weight history including the individual’s highest and lowest weights and the weight he or she would like to be now. For women, it is useful to know the weight at which menstruation last occurred, because it provides an indi-cation of what weight is normal for that individual. The patient should be asked to describe a typical day’s food intake and any food restrictions and dietary practices such as vegetarian-ism. The psychiatrist should ask whether the patient ever loses control over eating and engages in binge-eating and, if so, the amounts and types of food eaten during such episodes. The use of self-induced vomiting, laxatives, diuretics, enemas, diet pills, and syrup of ipecac to induce vomiting should also be queried.

Probably the greatest problem in the assessment of pa-tients with anorexia nervosa is their denial of the illness and their reluctance to participate in an evaluation. A straightforward but supportive and nonconfrontational style is probably the most useful approach, but it is likely that the patient will not acknowl-edge significant difficulties in eating or with weight and will ra-tionalize unusual eating or exercise habits. It is therefore helpful to obtain information from other sources such as the patient’s family.

Physical Examination and Laboratory Findings

The patient should be weighed, or a current weight should be obtained from the patient’s general physician. Blood pressure, pulse and body temperature are often below the lower limit of normal. On physical examination, lanugo, a fine, downy hair nor-mally seen in infants, may be present on the back or the face. The extremities are frequently cold and have a slight red–purple color (acrocyanosis). Edema is rarely observed at the initial pres-entation but may develop transiently during the initial stages of refeeding.

The basis for laboratory abnormalities is presented in the earlier section on pathophysiology. Common findings are a mild to moderate normochromic, normocytic anemia and leukope-nia, with a deficit in polymorphonuclear leukocytes leading to a relative lymphocytosis. Elevations of blood urea nitrogen and serum creatinine concentrations may occur because of dehydra-tion, which can also artificially elevate the hemoglobin and he-matocrit. 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.

Differences in Presentation

The symptoms of anorexia nervosa are remarkably homogene-ous, and differences between patients in clinical manifestations are fewer than in most psychiatric illnesses. As described before, younger patients may not express verbally the characteristic fear of fatness or the overconcern with shape and weight, and some patients with longstanding anorexia nervosa may express a desire to gain weight but be unable to make persistent changes in their behavior. It has been suggested that in other cultures, the ration-ale given by patients for losing weight differs from the fear of fatness characteristic of cases in North America.

Men have anorexia nervosa far less frequently than women. However, when the syndrome does develop in a man, it is typical. There may be an increased frequency of homosexuality among men with anorexia nervosa.