Bulimia nervosa

Description

Bulimia nervosa is an eating disorder that affects women 9-10 times more often than men. It has three key features:

• Intense preoccupation with body weight and shape

• Repetitive episodes of binge eating (uncontrollably eating a large quantity of food in a defined period—usually less than two hours)

• Routinely taking extreme measures to prevent weight gain, including self induced vomiting, fasting, excessive exercise, and misuse of laxatives and diuretics.

The condition is characterised by the patient's inability to control the urge to indulge in binge eating. Medical complications are caused by the weight reducing behaviours, particularly vomiting and laxative misuse. The frequency of these behaviours is, on average, at least twice a week for three months. Episodes may be spontaneous or planned and can be triggered by stress, intense hunger, or dysphoria. Patients are usually in the normal weight range.

Treatment

Despite the availability of effective treatments, few people with bulimia nervosa seek help. One study found that only 1 in 10 people with the condition are in treatment.¹

Treatments that are likely to work

Antidepressants

Antidepressants can reduce binge eating and purging, and improve depressive symptoms and attitude towards food. There is not enough evidence on how long the benefits last or for comparing the effects of different classes of antidepressants. Antidepressants and cognitive behaviour therapy are equally effective for bulimia nervosa, though dropout rates are higher with antidepressants, probably due to their side effects. For information on drug doses, see www.besttreatments.org/bulimianervosa.

Cognitive behaviour therapy

As with antidepressants, cognitive behaviour therapy can reduce binge eating and purging, and improve depressive symptoms and attitude towards food. It may be preferable to medication in patients who are sensitive to, or wish to avoid, side effects of medication. Cognitive behaviour therapy and other psychological treatments seem to be equally good at treating binge eating, although cognitive behaviour therapy is better at improving depression scores. There is some evidence that cognitive behaviour therapy has long term benefits in treating bulimia, but there is insufficient evidence about patients' characteristics that predict response.

Combination treatment with antidepressants and psychotherapy

Remission rates of some (but not all) symptoms are higher with combination treatment than with either treatment alone. Patients are more likely to withdraw from combined treatment or antidepressants alone than from psychotherapy alone. Some trials of combination treatment with antidepressants and psychotherapy have excluded patients with severe comorbid conditions such as depression and substance abuse, yet these conditions are common in patients seen in a clinical setting.

Other psychotherapies

Other psychotherapies, such as interpersonal psychotherapy and dialectical behaviour therapy (see definitions on www.besttreatments.org/bulimianervosa), are better than control (being on a waiting list for treatment) at improving binge eating and other symptoms of bulimia. The few trials of these psychotherapies have been hampered by small sample sizes and lack of blinding. It remains unclear which of these many techniques works best.

Treatments that need further study

Antidepressants as maintenance

There is not enough evidence on whether antidepressants have a role as maintenance therapy. Two very small randomised controlled trials (total of 18 patients) found that maintenance treatment with a tricyclic antidepressant was no better than placebo.

Newer antidepressants

There have been no randomised controlled trials of the newer antidepressants mirtazapine, reboxetine and venlafaxine in treating bulimia nervosa.

Selective serotonin reuptake inhibitors other than fluoxetine

The only selective serotonin reuptake inhibitor shown to work in bulimia nervosa is fluoxetine.