Psychotherapy for bulimia nervosa and binging

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

The review aims to evaluate the psychotherapeutic treatments for those with binge eating syndromes, that have been tested in randomised controlled trials. Specifically, CBT therapy is 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. As well, the review aims 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.

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 Group Database of Trials; citation list searching and personal approaches to authors communication are 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, are sought for the purpose of this review.

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

To date, more than 1360 trials have been generated by searching and 63 trials have been evaluated in detail. Because of a relatively high number of exclusions (n=12) the trial inclusion criteria were broadened to include those with non-blinded outcome assessment, providing 25 trials for analyses. Because of incomplete published and available data, at best up to 10 studies had data available for any single analysis. The maximum number of total patients included in a single analysis is 543. The majority of studies (21) evaluate patients with bulimia nervosa of a purging type. CBT is superior to waiting list controls with respect to abstinence from binge eating (RR 0.64 CI.53-.78). CBT just fails to be significantly superior to other psychotherapies with respect to abstinence from binge eating (RR.79, CI.61-1.04). CBT in a full or less intensive form is not significantly superior to CBT in a pure self-help form. Augmentation of CBT with exposure therapy is not more effective than CBT alone. Non CBT-psychotherapies also have significantly greater abstinence rates in comparisons with wait-list controls, but there is a paucity of such studies (RR 0.67, CI.56-.81, n=3 studies). Funnel plots suggest a bias towards publication of positive outcome studies only.

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