Eating Disorders: Diagnosis and Treatment

Diagnosis

The American Psychiatric Association's diagnostic criteria for Anorexia Nervosa are summarized as follows:¹

• Refusal to maintain body weight at or above a minimally normal weight for age and height (eg, weight loss leading to maintenance of body weight less than 85% of that expected; or failure to make expected weight gain during period of growth, leading to body weight less than 85% of expected).
• Intense fear of gaining weight or becoming fat, despite being significantly underweight.
• Disturbance in the way in which one's body weight or shape is experienced, undue influence of body weight or shape on self-evaluation, or denial of the seriousness of the current low body weight.
• In postmenarcheal females, amenorrhea, ie, the absence of at least 3 consecutive menstrual cycles.

The condition is subclassified as either the restricting type or the binge-eating/purging type, depending on whether the individual regularly engages in binge-eating or purging behavior (eg, self-induced vomiting or the misuse of laxatives, diuretics, or enemas).

The diagnostic criteria for Bulimia Nervosa are summarized below:

• Recurrent episodes of binge eating during discrete periods of time (eg, within any 2-hour period), characterized by eating an amount of food that is definitely larger than most people would eat during a similar period of time, and a sense of lack of control over eating during the episode.
• Recurrent inappropriate compensatory behavior to prevent weight gain, such as self-induced vomiting; misuse of laxatives, diuretics, enemas, or other medications; fasting; or excessive exercise.
• Episodes of binge eating and inappropriate compensatory behaviors occurring, on average, at least twice a week for 3 months.

Several screening questionnaires are available for primary care clinicians. For example, in the questionnaire below, developed at St. George's Hospital Medical School in London in 1999, positive responses to 2 or more questions indicated a diagnosis of Anorexia or Bulimia, with a sensitivity and specificity of 100% and 87.5%, respectively:⁵

• Do you make yourself sick because you feel uncomfortably full?
• Do you worry you have lost control over how much you eat?
• Have you recently lost more than 14 pounds in a 3-month period?
• Do you believe yourself to be fat when others say you are too thin?
• Would you say that food dominates your life?

Laboratory studies should include a complete blood count, electrolytes, calcium, magnesium, phosphorous, blood urea nitrogen, creatinine, urinalysis, electrocardiogram, and thyroid function tests. Pregnancy testing is indicated in all females with amenorrhea. Bone-density testing and MRI of the brain may be indicated if osteoporosis or impaired cognition is suspected.

Treatment

Medical comorbitities, including electrolyte disturbances and dehydration, should be treated and, when possible, prevented.

Hospitalization is indicated for severe malnutrition (body weight less than 75% of ideal), suicidal ideation, electrolyte disturbances, dehydration, abnormal vital signs (eg, bradycardia, hypothermia), cardiac arrhythmias, and failure of outpatient treatment.

Vitamin and mineral supplementation may be necessary. An inpatient or outpatient structured eating program may help restore healthy eating habits.

Psychotherapy is a mainstay of treatment for certain eating disorders. Because drug therapy is, for the most part, ineffective for anorexia nervosa,⁶ psychotherapy is often the treatment of choice. However, not all forms of therapy have undergone rigorous testing. Family-based therapy appears to be more effective in anorexic adolescents (but not adults) than other therapeutic modalities. In adults, psychotherapy has been found to reduce anorexic behaviors in up to 60% of patients. However, more stringent assessment of the effects of cognitive-behavioral therapy indicated that only 17% of patients could be considered fully recovered.⁷

In persons with Binge-Eating Disorder, a disorder characterized by excessive bingeing without compensatory behavior, cognitive-behavioral therapy and interpersonal therapy reduced binge eating by 48% to 98%8 and produced abstinence rates of about 60%.⁶

Most studies show cognitive-behavioral therapy to be more effective than drug therapy for persons with Bulimia Nervosa.9 Fluoxetine was approved for treatment of Bulimia by the FDA and is significantly efficacious in about 60% of cases. Combining medication with psychotherapy improves the effectiveness of both treatments.⁶ Also, self-help manuals appear to be as effective as psychotherapy in reducing binge episodes for some patients.¹⁰

Group support in a structured setting can be very helpful. Groups based on principles of cognitive-behavioral or dialectic behavioral therapy, have been shown to be effective. Twelve-step programs such as Overeaters Anonymous are often effective as well.