Eating Disorders

Disturbances in eating behavior and attitudes severe enough to warrant a diagnosis affect perhaps some 6 percent of all adolescent and adult women in this country, making it one of the most common psychiatric disorders to affect this population. There are four categories of eating disorders recognized by the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) (American Psychiatric Association, 1994): Anorexia Nervosa (AN), Bulimia Nervosa (BN), Eating Disorder Not Otherwise Specified (EDNOS), and Binge Eating Disorder (BED).

AN and BN share many clinical features and this article will be devoted primarily to these two eating disorders. EDNOS and BED and eating disorders in men are discussed separately at the end of this article.

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Anorexia Nervosa

The term anorexia nervosa was coined by Sir William Gull in 1874, but many early reports of cases of self-starvation exist in the medical literature. AN affects about 0.5-1 percent of young women in the West. The main features of AN are emaciation (very low body weight), behavior aimed at producing weight loss (extreme dieting, purging, excessive exercise), and a morbid fear of becoming fat. Whereas the DSM-IV lists amenorrhea as one of diagnostic criteria, its value is being increasingly questioned because the absence or presence of amenorrhea does not materially alter the patient’s response to treatment or the outcome. There are two types of individuals with AN: those who predominantly restrict their food intake and those who binge and purge.

AN typically begins in the teenage years in young women who have embarked on dieting to lose weight. After some initial weight loss the self-starvation becomes more rigorous, amenorrhea sets in, fear of becoming fat intensifies, and emaciation occurs. About 40 percent of these individuals then develop binge eating and purging while still emaciated. After a few years about one-third begin to recover and regain normal weight, although the period of recovery is often characterized by chaotic eating: periods of fasting interspersed by binge eating and sometimes vomiting (i.e., a period of Bulimia Nervosa). About one of four remains chronically ill with AN. AN is a psychiatric disorder that has a high mortality; those with AN are perhaps five times more likely to die than expected of the general population. Most of the premature deaths occur as a result of the emaciation and complications or of suicide.

Many medical complications can occur as a result of the self-starvation and severe weight loss. Among those who purge, severe metabolic abnormalities may cause cardiac arrest (leading to sudden death) and kidney failure. Fatigue, intolerance of cold, depression, anxiety, obsessive-compulsive behaviors, insomnia, preoccupation with eating and weight, and low self-esteem plague most patients with AN, who have hopes that maintaining a very low weight would be the answer to all their problems. For those with the bulimic subtype of Anorexia Nervosa, alcohol and substance abuse, shoplifting, sexual promiscuity, and self-mutilation may also occur.

Treatment consists of restoration of the malnourished state, correction of metabolic disturbances, normalization of the disturbed eating behaviors, restructuring of abnormal eating and self-attitudes, and treatment of concommittant depression and anxiety. For those with very low body weight or severe metabolic disturbance, a period of inpatient treatment may be necessary. Osteopenia and osteoporosis may require more specialized treatment than just nutritional/weight restoration. A combination of psychotherapy, nutritional counseling, and medical treatment is almost always needed, whether the patient is treated in an inpatient or outpatient setting. For young patients living at home, family therapy focused initially on helping the family to help the patient normally and gain weight, and later to help the patient develop individuation and form an independent identity, is particularly helpful. Therapy aimed at increasing motivation for recovery may help those who are reluctant to give up their thinness. Antidepressant medications, particularly the serotonergic agents, may be useful in preventing relapse in AN restrictive subtype patients who have regained healthy weight, and in improving mood in those who have concommittant depression or anxiety or obsessive-compulsive features. In general, medications are not useful in helping AN patients to gain weight.

Bulimia Nervosa

Bulimia Nervosa (BN), a term coined by Gerard Russell in 1979, affects about 2 percent of young women in the West, although the figure approaches 5 percent if less severe cases are also included. Its main features are eating binges accompanied by a feeling of loss of control over eating, and purging behavior to get rid of the calories of the binge by self-induced vomiting and/or laxative abuse. Excessive exercising, abuse of diet pills to curb the urge to binge, abuse of diuretics to lose weight (although no calories are lost in this forced diuresis), and abuse of opecae to induce vomiting, which may cause muscle (and heart) damage, may also occur. Occasionally individuals with BN may chew large quantities of food when the urge to binge arises and then spit out instead of swallowing the food. In contrast to AN, patients with BN, by definition, have normal or high body weight. An emaciated patient with bulimic features would be diagnosed as AN, Bulimic subtype, not BN.

Onset of BN is typically in the late teens. After a period of dieting and weight loss and sometimes a phase of frank AN the urge to binge becomes overpowering. A sense of relief is soon followed by tremendous guilt during the binge, which, together with the discomfort of an over distended stomach, compels the individual to purge. Cycles of binge, purge, and self-starvation develop and the individual becomes consumed with thoughts of weight and eating. Depression sets in and sometimes the abnormal eating behaviors occupy the majority of the waking hours of the individual’s life. In a small proportion of individuals with BN, self-induced vomiting and self-starvation precede the onset of hinging.

Perhaps because of the shame, depression, and feelings of loss of control, more individuals with BN than individuals with AN seek help. Perhaps about two-thirds recover in a few years, whereas one-third have periods of remission alternating with periods of relapse. Major complications such as cardiac arrest, esophageal or gastric bleeding, and severe electrolyte disturbances may occur.

Treatment consists usually of cognitive-behavioral therapy to change the individual’s dysfunctional thoughts about weight and eating as well as self-concept and interpersonal relationships. Self-monitoring of eating behavior and attendant thoughts, identification of the antecedents to a binge/purge episode, and the restructuring of dysfunctional thoughts and behaviors to prevent binge/purge are some of the key components to this treatment. Also effective is interpersonal psychotherapy that focuses on issues such as role transition, loss, and interpersonal conflict. Treatment may be given in individual or group format. More recently self-help techniques that utilize treatment manuals and usually guided by a counselor have been found to be helpful and may be used as the first step of treatment, and cognitive-behavioral therapy or interpersonal therapy are used for those who failed to respond to self-help. Antidepressants, particularly the serotonergic agents, are sometimes useful in decreasing the dysphoria and the urges to binge. They are best used in combination with psychotherapy.

Eating Disorders in Non-Western Cultures

As already mentioned, AN and BN are becoming more common in developed and developing Asian countries such as Japan, China, Taiwan, and Hong Kong. By and large, patients with BN in these non-Western countries demonstrate identical clinical features to their counterparts in the West. However, about 30 percent of individuals with AN in non-Western countries do not show the characteristic morbid fear of fatness that is considered to be a sine qua non of AN in the West. This suggests that reasons for the strive for thinness may be different for individuals with AN in different cultures, but the implications of this finding remain to be clarified.

Binge Eating Disorder

Binge eating was first described by Albert Stunkard in 1954 in the context of eating disturbances in obese individuals, along with night eating and eating without satiation. BED affects some 2-3 percent of adults in the general population and 8 percent of those who are obese. In contrast to the preponderance of females in AN and BN, BED affects men and women about equally. Other differences between BED and BN/AN are that BED is probably at least equally common among ethnic minorities as among Whites, the age at presentation is older (3050 years vs. teens and late 20s), and most individuals with BED are overweight or obese. Although individuals with BED share many of the eating and self-attitude disturbances of individuals with BN, there is little “crossover” of individuals in these categories, that is, few people with BN develop BED or vice versa in longitudinal studies. Treatment consists of cognitive—behavior therapy which improves the eating behavior and attitudes, and in a small proportion of obese individuals with BED, this improvement is accompanied by some weight loss. BED seems to have a better prognosis than BN/AN, and individuals with BED seem to recover from their disorder in a few years, although the long-term outcome of BED remains unclear.

Eating Disorder Not Otherwise Specified

Currently, EDNOS is a category for all those individuals who have eating disturbances but do not meet specific criteria for AN, BN, or BED. For instance, an individual who has lost some weight but has not fallen below a body mass index (BMI) of 17 kg/ m2 would be given a diagnosis of EDNOS and not AN. Another example is an individual who binges and purges but not as frequency as twice a week or not for as long as 3 months will be given a diagnosis of EDNOS. Some studies have found that individuals with EDNOS may not have a more favorable prognosis than those diagnosed with AN or BN. It is certainly advisable that EDNOS individuals should get treatment for their eating disorder.

Eating Disorder in Men

AN and BN affect many more women than men; the female-to-male ratio in the majority of studies is about 10:1. Men with AN/BN are more concerned about muscularity than thinness, more likely to have a comorbid alcohol/substance use disorder, and of course do not meet criteria for menstrual disturbance. In men with AN, loss of sexual appetite secondary to lowered testosterone, which occurs as a result of weight loss, is gradual and unlikely to be a spontaneous complaint. Aside from these differences, the clinical features of AN/BN in men are essentially the same as those in women.

Risk factors for pathogenesis of AN/BN in men are probably similar to those in women, although several studies have found that sexual orientation and premorbid obesity may be specific risk factors for men: about 20 percent of males with AN/BN have a homosexual orientation, and premorbid obesity affects about 50 percent of men with AN/BN. Treatment and outcome are essentially similar to those for women.

As mentioned, BED is almost as common in men as in women; most studies have found a female-to-male preponderance of 3:2. Again, the clinical features of BED between the genders are similar. Treatment for BED in men is similar to that for women, although there has been little systematic study.

There is little data on outcome of BED in men, but there is no obvious reason to expect that it would be different.

Causes of AN and BN

Epidemiologic studies have found that AN and BN occur much more commonly in young White females in industrialized and developed countries. Non-White immigrants in Western countries such as Arab college students in London or Chinese young women in Toronto are more likely to develop AN or BN than their counterparts in their country of origin. Many case reports also suggest that AN and BN are becoming much more common in developed, industrialized Asian countries such as Japan and Hong Kong. These evidences indicate that there is a sociocultural influence on the pathogenesis of AN and BN.

Family studies have found that AN and BN tend to run in families and that there is cross-transmission of AN and BN in families (i.e., relatives of individuals with AN are more likely to have BN and vice versa). Twin studies have found that the concordance rates of AN and BN (i.e., both twins having the disorder) are higher in monozygotic (identical) than dizygotic (fraternal) twins. Large-scale population twin studies have suggested that both environmental and genetic influences are probably equally important in the development of these eating disorders.

Efforts to locate the genes that may be involved in the development of AN and BN have focused on genes involved in the control of feeding and mood. Genes involved in control of neurotransmitters, particularly those involved in serotonergic neurotransmission, are also being studied. No definitive results have emerged from these efforts but the search continues.

Environmental factors point to the role of dieting behavior in precipitating the onset of the eating disorders. The population that is most often engaged in dieting to control or lose weight is also the population that is most commonly afflicted with AN and BN (i.e., young women in the West), and several longitudinal studies have found that young women who are dieting are much more likely to develop AN or BN at follow-up. Other factors that may be involved include an overabundance of easily available food, relaxation of rules governing eating behaviors, increasing prevalence of obesity and the attendant emphasis on dieting to control weight, increasingly complex roles for women in an industrialized society, and childhood sexual abuse.

Some studies have found that the risk factors for the development of AN and BN may be different. Personality traits such as perfectionism, obsessimality, low risk taking, and negative self-evaluation may be more relevant for the development of AN, whereas premorbid obesity, rigorous dieting, and family history of obesity are more important for BN. These findings await confirmation.

In summary, it seems likely that genetic factors predispose certain individuals to develop an eating disorder, and that environmental (such as dieting to control weight) and developmental (such as onset of puberty and attendant weight gain) factors may trigger the expression of such factors.


Although the prediction in the 1980s that the eating disorders may reach epidemic proportions has not materialized, these disorders nevertheless constitute a severe health hazard for a significant minority of women. There is also evidence to indicate that they are becoming more common in some developed and developing non-Western countries. Unfortunately, progress in treatment and prevention has been slow, AN patients have a high mortality, and many individuals with AN and BN become chronically ill. Meanwhile, obesity has become a real public health issue, and although obesity is not classified as an eating disorder, some of its underlying mechanisms such as those involved in eating and weight control, as well as the social and cultural context that breeds it, may have much in common with those that underlie the eating disorders. One can hope that a broad-based research program to better our understanding of the biopsychosocial factors associated with the eating disorders and with obesity will bring more effective prevention and treatment.


  1. American Pyschiatric Association. (1994). Diagnostic and statistical manual of mental disorders (4th ed.) Washington, DC: Author.
  2. Brumberg, J. J. (1989) Fasting girls. New York: Plume.
  3. Fairburn, C. G. & Brownell, K. D. (Eds.). (2002). Eating disorders and obesity (2nd ed.). New York: Guilford.
  4. Hsu L. K. G. (1990). Eating disorders. New York: Guilford.

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