To examine the effectiveness of an Internet Based Therapy (IBT) for Bulimia Nervosa (BN), when compared to a brief psychoeducational group therapy (PET) or a waiting list (WL).

93 female BN patients, diagnosed according to DSM-IV criteria. An experimental group (31 IBT patients) was compared to two groups (31 PET and 31 WL). PET and WL were matched to the IBT group in terms of age, disorder duration, previous treatments and severity. All patients completed assesment, prior and after treatment.

Considering IBT, mean scores were lower at the end of treatment for some EDI scales and BITE symptoms scale, while the mean BMI was higher at post-therapy. Main predictors of good IBT outcome were higher scores in EDI perfectionism and higher scores on reward dependence. Drop-out was related to higher SCL-obsessive/compulsive (p=0.045) and novelty seeking (p=0.044) scores and lower reward dependence (p=0.018). At the end of the treatment bingeing and vomiting abstinence rates (22.6% for IBT, 33.3% for PET, and 0.0% for WL; p=0.003) and drop-out rates (35.5% IBT, 12.9% PET and 0% WL; p= 0.001) differed significantly between groups. While the concrete comparison between the two treatments (IBT and PET) did not evidence significant differences for success proportions (p=0.375), statistical differences for drop-out rates (p=0.038) were obtained.

The results of this study suggest that an online self-help approach appears to be a valid treatment option for BN, especially for people who present lower severity of their eating disorder (ED) symptomatology and some specific personality traits.