Treatment outcome research of enhanced cognitive behaviour therapy for eating disorders: a systematic review with narrative and meta-analytic synthesis.

Enhanced cognitive behaviour therapy (CBT-E) has recently generated interest as a potentially useful treatment for eating disorders (ED). In the current study, we conducted a systematic review of the outcome literature on CBT-E, with both narrative and meta-analytic synthesis. We included single-group uncontrolled pre-post design studies and randomised control trials (RCTs) of CBT-E, which allowed us to include a larger number of studies, and also compare the two methodologies in terms of effect size. The primary analysis included 15 CBT-E studies with a total of 948 participants. Narrative synthesis examined bingeing and purging episodes, BMI change, and follow-up results. A large, statistically significant effect supported CBT-E as a treatment for all EDs (g = 1.06). When comparing methodologies, both pre-post design studies (g = 1.26) and RCTs (g = 0.82) yielded large effects. Narrative synthesis outlined reductions in ED behaviours and increases in BMI which were maintained at follow-up. Limitations include that further RCTs of CBT-E are needed to establish clinical effectiveness of this treatment approach for all EDs; however, results from narrative exploration indicate this endeavour would be worthwhile. Despite the limitations, this study provides additional support for CBT-E as a successful treatment across the range of EDs.