Ask the Expert: Eating Disorders

Interpretation of results of the evaluation with the patient can be a pivotal point in their management. As physicians, psychiatrists are uniquely able to help patients make the connection between behavior (e.g., restrictive eating or purging) and signs, symptoms, and laboratory test results. For example, restrictive eating results in weight loss and amenorrhea that contribute to the development of osteopenia, an unwanted physiological complication for most patients. Another example would be purging by vomiting (a behavior that can result in hypokalemia and predispose to potentially fatal cardiac arrhythmias). This psychotherapeutic use of signs, symptoms, and laboratory tests is a strategy that can often aid the patient in overcoming denial and facilitate entry into formal treatment.

Cognitive-behavioral therapy is the most effective treatment for BN and can be provided in individual or group sessions over the course of 8–20 weeks (8). There are three phases to classic CBT–BN. The first phase is education about the theory underlying the maintenance of disturbed eating and dysfunctional weight control behavior (for example, restrictive eating, purging by vomiting, laxative abuse, or over-exercise). Using a diary format, the second phase is geared to identifying the frequency and timing of the problematic behavior. Events or factors preceding and following these behaviors are identified and recorded. The third phase is finding ways to alter the problematic behavior unique to the patient utilizing a specific sequence of behavioral tasks and “experiments.” Between 30% and 50% of patients who start classic CBT treatment cease binge eating and purging, but the rest either drop out of treatment or achieve a reduction, but not a cessation, of binge eating and purging. In the last few years CBT has been enhanced (CBT-E) to promote recovery in patients who have comorbid disorders (9). Strategies are included designed to impact core low self-esteem and promote coping with interpersonal life. Although there are self-help manuals that are very useful, the most effective outcomes are with experienced therapists who have received specialized training in CBT.

CBT has been studied for patients with AN and with BED (10). Thus far, the evidence for effectiveness in AN is weak. However, CBT for BED is effective in reducing episodes of binge eating; but among the large minority who are overweight or obese, CBT is not helpful in weight reduction.

Although manualized self-help is not as effective as individual or group treatment led by trained therapists, reduction in symptoms can occur; however, nonadherence and high drop-out rates are common. Patients with BED are more likely to complete self-help and more likely to benefit than are patients with BN. Guidance by health care professionals can improve the outcome in patients with BN (11).

Fluoxetine (trade name Prozac) is the only medication approved by the Food and Drug Administration (FDA) for any of the three major eating disorders. It is a selective serotonin reuptake inhibitor. It is only approved for BN at a recommended dose of 60 mg for adults only, although it is often effectively used off-label for adolescents with BN. Unfortunately, it is often used inappropriately for underweight AN patients; several studies have found fluoxetine to be ineffective in AN. This may be because some underweight AN patients have inadequate intake of 5-hydroxytryptophan (an amino acid) that is thought to be a precursor to serotonin. If this results in low levels of serotonin in the brain, a medication that inhibits reuptake of serotonin would be expected to be ineffective.

Multiple medications have been tried for AN including the atypical antipsychotics, but the results have been disappointing (12). Although in one randomized placebo-controlled trial (13) olanzapine was found to decrease minimally the length of time required to achieve ideal body weight, few eligible patients agreed to participate in the trial and the drop-out rate was high. The drug is generally unacceptable to patients because it can cause weight gain. Very few placebo-controlled randomized drug trials have been completed with AN patients.

Although there are currently no FDA-approved medications for BED, research in this area is active (14). Multiple antidepressants, especially the selective serotonin reuptake inhibitors, have been found to reduce binge eating in the short term, but in the large minority of patients who are overweight or obese, weight loss has not occurred. Although topiramate has been found to reduce both binge eating and weight, there are serious side effects that limit its usefulness including trouble concentrating, word-finding difficulty, and metabolic acidosis.

This exciting recent development utilizes the family to promote weight restoration among adolescents with AN (15). There are three phases to treatment. In the first phase, the parents take over control of the eating of the adolescent and, using guidance from the family therapist, ensure consumption of the prescribed calories until weight gain is steady and close to ideal body weight. In the second phase, control of eating is gradually transferred to the adolescent. In the third phase, individual therapy with the adolescent begins with the goal of ensuring achievement of appropriate developmental steps.

The first phase of this treatment cannot usually be provided in a general psychiatric practice because multiple lengthy sessions are often necessary, including direct supervision of meals in the presence of the family therapist. However, by the time the second phase begins and therapy to ensure achievement of normal developmental steps is needed, a psychiatrist specializing in the treatment of adolescents could be very effective.