Management and treatment strategies in bulimia nervosa
Uncomplicated bulimia nervosa can be treated in primary care (given access to appropriate support services), referral should be made if there is a lack of progress, the patient is pregnant or has a pre-existing condition such as diabetes.
General considerations about the patients health or mental wellbeing may also prompt referral as should suicidal tendencies. With the most effective treatments 50% of patients can be expected to be free of symptoms between two and 10 years after diagnosis. 20% of patients will develop chronic bulimia nervosa and the remaining 30% were either follow a relapsing and remitting course or develop chronic subclinical bulimic symptoms (other studies show even larger numbers in sustained remission – described in the NICE guideline).
Although long-term follow-up studies in this condition are few, it seems that untreated, the majority of bulimics will continue to be symptomatic for many years.
Cognitive behavioural therapy has strong evidence to support its use. A specific therapy has been developed for use in bulimia and it utilises three distinct but overlapping phases:-
- Education – the patient and where appropriate the carer receive education dealing with the aetiology, risk factors, clinical features, epidemiology and treatments for bulimia nervosa. Using this information the patient is given strategies for resisting the urge to binge or purge. A food diary may be introduced with encouragement for the patient to eat normal portions of food more regularly.
- Behavioural experiments - in this phase patient is encouraged to broaden their diet and introduce food they have been avoiding. The patient's beliefs around certain food categories are explored and the introduction of previous “forbidden” elements is tried.
- Maintenance phase - strategies to avoid relapses are agreed, coping mechanisms for relapses are introduced.
A Clinical Evidence report on 34 randomised controlled trials of CBT showed a significant increase in the proportion of patients abstaining from a binge-purge cycle of 43% with only 5% in the control group abstaining.
The same review uncovered insufficient evidence to recommend any other form of psychotherapy. Guided self-help cognitive behavioural therapy conducted in the primary care setting was as good as specialist CBT in one randomised control trial.
The use of antidepressant medication in the treatment of bulimia has been studied in adults. There is no evidence base for the use in adolescents and they do not have a licence for use in this indication. In adolescents drug treatment should not therefore be a first line intervention.
In adults there is evidence for the efficacy of tricyclic antidepressants, irreversible monoaimine oxidase inhibitors (but not moclobamide) and to a lesser extent SSRIs.
There is also evidence that a combined approach of Cognitive Behavioural Therapy (CBT) and antidepressant use enhances the effect of CBT. Doses of antidepressants used in the trials are similar to those used to treat depression (with the exception of fluoxetine at 60mg daily).
It is thought that the use of irreversible monoaimine oxidase inhibitors may cause further problems, as the exclusion of tyramine from the diet may focus the patient further on food.
NICE clinical recommendations in bulimia nervosa
- As an alternative or additional first step to using an evidence-based self-help programme, adults with bulimia nervosa may be offered a trial of an antidepressant drug.
- Patients should be informed that antidepressant drugs can reduce the frequency of binge eating and purging, but the long-term effects are unknown. Any beneficial effects will be rapidly apparent.
- Selective serotonin reuptake inhibitors (SSRIs) (specifically fluoxetine) are the drugs of first choice for the treatment of bulimia nervosa in terms of acceptability, tolerability and reduction of symptoms.
- For people with bulimia nervosa, the effective dose of fluoxetine is higher than for depression (60 mg daily).
- No drugs, other than antidepressants, are recommended for the treatment of bulimia nervosa.
And when comparing a combined approach of antidepressants and CBT verses CBT alone NICE makes the following points:-
- There have been few comparisons of psychological and pharmacological treatments, and their combination, with the result that any practice recommendations must be tentative.
- Few studies have included post-treatment follow-up periods, a problem with almost all the studies that have used drugs.
- The comparisons of cognitive behavioural therapy – bulimia nervosa (CBT-BN) with antidepressant drugs indicate that CBT-BN is the more potent treatment.
- The combination of CBT with antidepressant drugs is superior to antidepressant drugs on their own.