Eating Disorders

September 1, 2011

Eating disorders (ED) are classified in the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) on the basis of symptom clusters, characterized by severe disturbances in eating behavior and excessive concern about body shape or weight. Patients generally deny symptoms, are reluctant to seek help despite significant medical and psychiatric comorbidity, and are brought to care by family worried about their severe weight loss.

Anorexia nervosa (AN) includes an intense fear of gaining weight, refusal to maintain a normal weight, disturbed perception of one’s own shape or size, and, if female, amenorrhea of at least three consecutive cycles. Anorexia nervosa is subcategorized as (a) restricting (severe diet/low intake) or (b) binge eating/purging type (self-induced vomiting, misuse of laxatives, diuretics, or enemas). Comorbid symptoms include depression or sadness, social withdrawal, irritability, insomnia, or decreased sexual interest. Depression may be secondary to the physiological sequelae of semistarvation and resolve only after partial or complete weight restoration. Obsessive-compulsive features like frequent thoughts of food, hoarding food, picking/pulling apart small portions of food or collecting recipes, and concerns of eating in public are common.

Bulimia nervosa (BN) includes recurrent episodes of out-of-control, excessive or binge eating (occurring on an average, at least twice a week for 3 months), and selfevaluation, unduly influenced by body shape and weight. Individuals are typically ashamed and binge eat in secrecy. Unlike anorexia nervosa, bulimia nervosa patients are typically within normal weight range and restrict their total caloric consumption between binges. Patients with Bulimia nervosa may have difficulties with impulse regulation and substance abuse.

Many patients, particularly in younger age groups, have a combination of Eating Disorders symptoms that cannot be easily categorized as either Anorexia nervosa or Bulimia nervosa and are technically diagnosed as eating disorders—not otherwise specified (ED-NOS). The Eating Attitudes Test, Eating Disorders Inventory, or Body Shape Questionnaire may be helpful in assessing Eating Disorders.

Anorexia nervosa often begins in the midteens and affects up to 4% of adolescents and young adults. In females, the lifetime prevalence of Anorexia nervosa ranges from 0.5% to 3.7% when more broadly defined while Bulimia nervosa ranges from 1.1% to 4.2%. Both are 6 to 10 times more common in females, and are more prevalent in industrialized societies. Rates are rising in countries like Japan and China, where women are increasingly exposed to cultural change and modernization. In the United States, eating disorders are common in young Hispanic, Native American, and African American women, but are still less frequent than in Caucasian women. Female athletes involved in running, gymnastics, or ballet, and male bodybuilders and wrestlers are at greater risk.

Biological and psychosocial factors are implicated in the pathophysiology, but exact mechanisms remain unknown. Endogenous opioids may reduce hunger in patients with Anorexia nervosa, while endorphin levels increase after purging and initially induce feelings of well-being. Diminished neurotransmitter (norepinephrine) turnover and activity are suggested by reduced 3-methoxy-4hydroxyphenylglycol in the urine and cerebrospinal fluid of some patients with Anorexia nervosa. Antidepressants often benefit patients with Anorexia nervosa or Bulimia nervosa and implicate a role for the neurotransmitters serotonin and norepinephrine. Starvation from Anorexia nervosa or Bulimia nervosa results in hypercortisolemia (elevated blood cortisol), nonsuppression of dexamethasone, suppression of thyroid function and amenorrhea (absence of menstrual periods). Computerized tomographic (CT) studies of the brain may show enlarged sulci and ventricles (abnormal brain structure), a finding that is reversed when patients with Anorexia nervosa gain weight. Positron-emission tomography (PET) scan indicates higher metabolism in the caudate nucleus (a structure in the brain) during the anorectic state than after hyperalimentation (enriched tube or intravenous feeding). Firstdegree female relatives and monozygotic (identical) twins of patients with Anorexia nervosa have higher rates of Anorexia nervosa and Bulimia nervosa. Children of patients with Anorexia nervosa have a lifetime risk for Anorexia nervosa which is 10-fold that of the general population (5%). High levels of hostility, chaos, and isolation and low levels of nurturance and empathy are reported in families of children presenting with ED. Some believe self-starvation develops as adolescents struggle to be unique and independent, yet respond to societal pressures to be slender.

Any medical illness like malignancy, brain tumors, epilepsy, gastrointestinal disease, or AIDS that is associated with weight loss can simulate Anorexia nervosa and sometimes Bulimia nervosa. Likewise, patients with major depression may have a decreased appetite but no associated fear of obesity or body image disturbance, unless a comorbid ED exists. Patients with somatization disorder do not generally express a morbid fear of obesity, and are less likely to have severe weight loss or amenorrhea. Patients with schizophrenia may have delusions about food being poisoned but rarely are concerned with caloric content. Kluver-Bucy syndrome is a rare condition characterized by hyperphagia (excessive eating), hypersexuality, and compulsive licking and biting. Klein-Levin syndrome, another uncommon disorder, is more frequent in men, and consists of hyperphagia and periodic hypersomnia (excessive sleeping).

Medical Comorbidity of Eating Disorders. Complications are related to weight loss and purging (vomiting and laxative abuse).


A comprehensive treatment plan includes a combination of nutritional rehabilitation with behavior changes, psychotherapy, and medication. Treatment guidelines are readily available with an abridged, up-to-date version at

Indicators for hospitalization include weight less than 75% of the estimated healthy weight, serious electrolyte or metabolic abnormalities, significant vital sign abnormalities, failure of intensive outpatient intervention, or comorbid psychiatric illness, particularly suicidality. Nutritional rehabilitation supports 2-3 lb/week weight gain for a hospitalized patient and 0.5-1 lb/week for an individual treated as an outpatient. Intake levels should start at 30-40 kcal/kg per day in divided meals. Inpatient treatment includes monitoring daily morning weights, vital signs, fluid intake and output, and frequent physicals to detect circulatory overload, refeeding edema, or bloating. Monitoring low potassium or phosphorus levels and obtaining an electrocardiogram will help to detect medical complications. Stool softeners and not laxatives are preferred for treatment of constipation, while vitamins and mineral supplements replenish deficiencies. Praising positive effort yet restricting exercise and purging are important behavioral strategies. Close supervision and restricted access to bathrooms for at least 2 hr after meals may be necessary.

Psychosocial treatments are required during hospitalization and after discharge. Commonly used models include dynamic expressive-supportive therapy and cognitive behavioral techniques. Planned meals with self-monitoring as well as exposure and response prevention can strengthen gains. Support or therapy groups or 12-step programs like Overeaters Anonymous may provide adjunctive treatment and diminish relapse. Family therapy and marital therapy is helpful with dysfunctional family patterns and interpersonal distress.

Medications for treatment of Anorexia nervosa can be initiated before or after weight gain. Individuals can maintain normal eating behaviors as well as treat associated psychiatric symptoms. Antidepressants like serotonin-specific reuptake inhibitors, for example, fluoxetine (Prozac) are commonly considered, particularly if, depressive, obsessive, or compulsive symptoms persist in spite of or in the absence of weight gain. Tricyclic antidepressants should be used with caution due to greater risks of cardiac arrhythmias or hypotension. Occasionally, low doses of antipsychotics can be used for marked agitation with psychotic thinking. Antianxiety medications like benzodiazepenes can be helpful for extreme anticipatory anxiety before eating. Estrogen replacement alone does not generally appear to reverse osteoporosis or osteopenia, and unless there is weight gain, it does not prevent further bone loss. There is no evidence regarding efficacy of biphosphonates in treatment of associated osteoporosis. Agents which encourage bowel motility, such as metoclopramide are commonly used for bloating and abdominal pains due to gastroparesis and premature satiety (“fullness”) but require monitoring for drugrelated extrapyramidal side effects.

Antidepressants are also used to reduce the frequency of disturbed eating behaviors and treat comorbid depression, anxiety, obsessions, and impulsedisorder symptoms in Bulimia nervosa. Fluoxetine is currently approved by the Food and Drug Administration for Bulimia nervosa, but other antidepressants like sertraline (Zoloft), paroxetine (Paxil), citalopram (Celexa), imipramine, nortriptyline, desipramine, and monoamine oxidase inhibitors (MAOI) have also been used. Doses of tricyclic antidepressants and MAOI antidepressants parallel those used to treat depression, but higher doses of fluoxetine (60-80 mg/day) may be needed to treat Bulimia nervosa. Bupropion is contraindicated in purging bulimic patients, who have greater risk of seizures. Lithium remains an adjunct for comorbid bipolar disorders or treatment resistance.

As a general guideline, it appears that one third of individuals fully recover, one third retain subthreshold symptoms, and one third with higher psychiatric comorbidity remain chronically eating disordered. Long-term follow-up of Anorexia nervosa shows recovery rates ranging from 44% to 76% with prolonged recovery time, but mortality up to 20% is primarily from cardiac arrest or suicide. Short-term success with Bulimia nervosa is 50-70%, with relapse rates between 30% and 50% after 6 months. Although there are little long-term data on Bulimia nervosa, patients generally fare better as compared to Anorexia nervosa patients.

SEE ALSO: Adolescence, Anorexia nervosa, Binge eating disorder, Body image, Bulimia nervosa, Depression

Suggested Reading

  • American Psychiatric Association. (1994). Diagnostic and statistical manual of mental disorders (4th ed.). Washington, DC: American Psychiatric Association.
  • American Psychiatric Association. (2000). Eating disorders measures. Handbook of psychiatric measures (pp. 647-673). Washington, DC: American Psychiatric Association.
  • American Psychiatric Association Work Group on Eating Disorders. (2000). Practice guideline for the treatment of patients with eating disorders (revision). American Journal of Psychiatry, 15XSuppl. 1), 1-39.
  • Becker, A. E., Grinspoon, S. K., Klibanski, A., et al. (1999). Eating disorders. New England Journal of Medicine, 340, 1092-1098.
  • Kay, J., Sansone, R. A., et al. (2001). Eating disorders. Hospital Physician Psychiatry Board Review Manual, 5(2), 1-12.

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