Current treatment strategies for BN are limited. The total effective rate of pharmacotherapy and psychotherapy is only about 50%.The preliminary studies and clinical experience of this project indicate that :(1) fluoxetine, DBT and CBT were effective in controlling binge eating and purging behaviors in patients with BN;(2) the short-term efficacy of fluoxetine group is better than DBT group ;(3) treatment with fluoxetine is more convenient and easier to be accepted by Chinese patient and Chinese doctors. BN patients who had poor response to fluoxetine with adequate dosage and duration would receive a secondary treatment, and randomly assigned to three groups: topiramate, fluoxetine +CBT, fluoxetine +DBT.This study was designed as a multicenter randomized controlled study, in which 550 patients with bulimia were enrolled. During 1year of follow-up, the onset time, short-term and long-term efficacy, duration of treatment and the cost of each treatment strategies would be observed and compared.

Bulimia nervosa (BN) is a kind of chronic mental disorder which is easy to relapse, characterized by repeated binge eating, compensatory behaviors to prevent weight gain and excessive attention to one's own weight and body shape. Current treatment strategies for BN are limited. The total effective rate of pharmacotherapy and psychotherapy is only about 50%. All countries have listed SSRI drugs (fluoxetine 60mg/d has the most evidence from studies, and it is the only drug which has regulatory approval for the treatment of BN by FDA) and cognitive behavioral therapy (CBT) as the first-line treatment for BN. Other commonly used treatments include topiramate and dialectical behavior therapy (DBT).The preliminary studies and clinical experience of this project indicate that :(1) fluoxetine, DBT and CBT were effective in controlling binge eating and purging behaviors in patients with BN;(2) the short-term efficacy of fluoxetine group is better than DBT group ;(3) treatment with fluoxetine is more convenient and easier to be accepted by Chinese patient and Chinese doctors. Based on these factors above, this study was designed using fluoxetine as the initial treatment. However, there is no evidence for patients who fail to respond to fluoxetine therapy to choose further treatment. As the result of fact, this study is proposed to adopt a two-stage sequential study design.BN patients who had poor response to fluoxetine with adequate dosage and duration would receive a secondary treatment, and randomly assigned to three groups: topiramate, fluoxetine +CBT, fluoxetine +DBT.This study was designed as a multicenter randomized controlled study, in which 550 patients with bulimia were enrolled. During 1year of follow-up, the onset time, short-term and long-term efficacy, duration of treatment and the cost of each treatment strategies would be observed and compared. Based on the comprehensive evaluation of the advantages and disadvantage of each strategies, an evidence-based optimal strategy could be formed. The factors influencing the initial therapeutic effect and sequential therapeutic effect of BN would also be explored. If the expected results are obtained, it will provide strong support for the formulation of optimal clinical treatment strategy for BN.

Inclusion Criteria:

• Have junior high school or above education level;
• Meet the diagnostic criteria of BN in DSM-5, body mass index (BMI)≥ 18.5kg /m2;
• Did not receive systematic nutrition treatment, psychiatric medication or any form of psychological treatment within 1 month before enrollment.
• Each patient must understand the nature of the study and sign an informed consent form.

Exclusion Criteria:

• those who meet DSM-5 except BN, such as substance abuse/dependence, depression, bipolar disorder, anxiety disorder, obsessive-compulsive disorder, high risk of suicide, strong destructive impulse or antisocial behavior;
• the patient has a serious primary or secondary physical disease, cognitive impairment, so that the patient can not complete the required symptom evaluation examination, psychological test;
• had received systematic nutritional treatment, individual and group psychotherapy;
• nearly 1 month to take neuroblockers, antidepressants, lithium, stimulants, antiepileptic drugs and other psychiatric drugs.
• for other reasons, the researchers considered it inappropriate to participate in this clinical trial.