Background The effectiveness of psychotherapeutic interventions for eating disorders (EDs) is widely studied in Europe, North America, and Australia/New Zealand. However, few controlled studies and no randomized controlled trials (RCTs) have been conducted in Japan despite the relatively high prevalence of EDs in the Japanese population. The aim of this study is to evaluate the effect of enhanced cognitive behavior therapy (CBT-E), an evidence-supported ED-focused form of cognitive behavior therapy (CBT), for the treatment of bulimia nervosa (BN) in Japan. Methods/design This multicenter RCT will compare CBT-E with treatment as usual (TAU), which is widely used in Japan. A group of 140 adult outpatients with a Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (DSM-5) diagnosis of BN, ≥18 years of age, a body mass index (BMI) > 17.5 and < 40 kg/m2 will be randomly assigned to CBT-E or TAU. Participants will be stratified by intervention site and BN severity. CBT-E participants will receive 20 sessions of focused form CBT-E for 20 weeks. Those in the TAU group will receive routine treatment provided by specialists. Assessment will be performed in a blinded manner prior to the start of treatment, after 6 weeks of treatment, at the end of treatment (20 weeks), and at follow-up at 40 and 80 weeks after the start of treatment. The primary outcome is the remission of BN, defined by the absence, in the previous 4 weeks, of symptoms required to meet the DSM-5 criteria for a diagnosis of BN. Secondary outcomes include the levels of ED psychopathology and impairment due to the ED, anxiety, depression, family function, and satisfaction with treatment. Discussion This will be the first RCT conducted in Japan to compare CBT-E and TAU for the treatment of BN. If CBT-E is found to be more effective than TAU, then the evidence would support its wider use for patients with BN in Japan. Because it is possible to train therapists who do not possess extensive specialist experience, wider use is also likely to be practically feasible. In addition, demonstrating the effectiveness of CBT-E in Japan would demonstrate that it could be successfully extended to additional world cultures and regions. Trial registration UMIN, UMIN000031625. Registered 7 Mar 2018.

中文翻译：

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日本神经性贪食症增强认知行为疗法的有效性：一项随机对照试验方案。

背景 饮食失调 (EDs) 心理治疗干预的有效性在欧洲、北美和澳大利亚/新西兰得到广泛研究。然而，尽管日本人群中 ED 的患病率相对较高，但在日本几乎没有进行过对照研究，也没有进行随机对照试验 (RCT)。本研究的目的是评估增强认知行为疗法 (CBT-E) 的效果，这是一种有证据支持的以 ED 为中心的认知行为疗法 (CBT)，用于治疗日本的神经性贪食症 (BN)。方法/设计 这项多中心 RCT 将 CBT-E 与在日本广泛使用的常规治疗 (TAU) 进行比较。一组140名成年门诊患者，精神疾病诊断与统计手册第五版（DSM-5）诊断为BN，≥18岁，体重指数（BMI）> 17.5 和 < 40 kg/m2 将随机分配到 CBT-E 或 TAU。参与者将按干预部位和 BN 严重程度进行分层。CBT-E 参与者将收到为期 20 周的 20 节集中形式 CBT-E 课程。TAU 组的人将接受专家提供的常规治疗。评估将在治疗开始前、治疗 6 周后、治疗结束时（20 周）以及治疗开始后 40 和 80 周的随访时以盲法方式进行。主要结果是 BN 的缓解，定义为在过去 4 周内没有满足 DSM-5 诊断 BN 标准所需的症状。次要结果包括 ED 精神病理学水平和 ED 引起的损害、焦虑、抑郁、家庭功能和对治疗的满意度。讨论 这将是日本第一个比较 CBT-E 和 TAU 治疗 BN 的 RCT。如果发现 CBT-E 比 TAU 更有效，那么证据将支持其在日本更广泛地用于 BN 患者。因为可以培训不具备丰富专业经验的治疗师，所以更广泛的使用也可能是切实可行的。此外，在日本展示 CBT-E 的有效性将证明它可以成功地扩展到其他世界文化和地区。试用注册UMIN，UMIN000031625。2018 年 3 月 7 日注册。因为可以培训不具备丰富专业经验的治疗师，所以更广泛的使用也可能是切实可行的。此外，在日本展示 CBT-E 的有效性将证明它可以成功地扩展到其他世界文化和地区。试用注册UMIN，UMIN000031625。2018 年 3 月 7 日注册。因为可以培训不具备丰富专业经验的治疗师，所以更广泛的使用也可能是切实可行的。此外，在日本展示 CBT-E 的有效性将证明它可以成功地扩展到其他世界文化和地区。试用注册UMIN，UMIN000031625。2018 年 3 月 7 日注册。