Psychotherapy for bulimia nervosa and binging

Bulimia nervosa and like syndromes, such as binge eating disorder, are common in young Western women. A specific manual based psychotherapy, cognitive behaviour therapy (CBT) has been developed for the treatment of bulimia nervosa (CBT-BN). Other psychotherapies, some from a different theoretical framework, and some modifications of CBT are also used.

To evaluate the efficacy of psychotherapeutic treatments for those with binge eating syndromes, that have been tested in randomised controlled trials. The efficacy of CBT in the specific treatment of bulimia nervosa and binge eating disorder was evaluated. CBT therapy was compared with waiting list or a non-treatment group, any other psychotherapy, CBT in a "pure self-help" form and CBT augmented by exposure and response therapy. In addition, the review aimed to evaluate the evidence for the efficacy of other psychotherapies when compared to a no treatment control group and to evaluate the evidence for the efficacy of other psychotherapies when compared to a 'placebo' therapy.

A handsearch of The International Journal of Eating Disorders since its first issue; database searches of MEDLINE, EXTRAMED, EMBASE, PSYCHLIT, CURRENT CONTENTS, LILACS, SCISEARCH, The Cochrane Collaboration Controlled Trials Register and the Cochrane Depression, Anxiety and Neurosis Controlled Trials Register; citation list searching and personal approaches to authors were used.

All studies that have tested any form of psychotherapy for adult patients with non-purging bulimia nervosa, binge eating disorder and/or EDNOS of a bulimic type, and which have applied a randomised controlled and standardized outcome methodology, were sought for the purpose of this review.

Data were entered into a spreadsheet programme, and into the REVMAN analysis program. Relative risk analyses were conducted of binary outcome data. The relative risk analysis was used rather than the odds ratio as the outcome measures proposed were not measuring a rare event (such as death) and the total number of studies was small. Standardized mean difference analyses were conducted of continuous variable outcome data, as the continuous outcome measures were not consistent across studies. Sensitivity analyses were conducted of a number of measures of trial quality. Data were not reported in such a way to permit subgroup analyses, but the effects of treatment on depressive symptoms, psychosocial and/or interpersonal functioning, general psychiatric symptoms and weight were examined where possible. Chi-square tests for homogeneity were done, at 5% level of significance, using a fixed effects model. Funnel plots to evaluate presence of publication bias were completed and are available in a text file upon request.

To date, more than 1365 trials have been generated by searching and over 100 trials have been evaluated in detail. Because of a relatively high number of original exclusions (n=12) the trial inclusion criteria were broadened to include those with non-blinded outcome assessment, providing 34 trials for analyses. Because of incomplete published and available data, at best up to 12 studies had data available for any single analysis. The maximum number of total patients included in a single analysis was 602. The majority of studies evaluated patients with bulimia nervosa of a purging type. The review supported the efficacy of cognitive-behavioural psychotherapy (CBT) and particularly CBT-BN in the treatment of people with bulimia nervosa and also (but less strongly due to the small number of trials) like eating disorder syndromes. CBT had been used with efficacy in group settings. Other psychotherapies were also efficacious, particularly interpersonal psychotherapy in the longer-term. Self-help approaches that used highly structured CBT treatment manuals, were promising albeit with more modest results generally, and their evaluation in bulimia nervosa approach merits further research. Exposure and response prevention did not appear to enhance the efficacy of CBT. Psychotherapy alone is unlikely to reduce or change body weight in people with bulimia nervosa or similar eating disorders.

There was a small body of evidence for the efficacy of cognitive-behaviour therapy in bulimia nervosa and similar syndromes, but the quality of trials was very variable (e.g. the majority were not blinded) and sample sizes were often small in comparison to pharmacotherapy trials. More trials are needed, particularly for binge eating disorder and other EDNOS syndromes, and trials evaluating other psychotherapies and less intensive psychotherapies.