Published on in Vol 12 (2023)

Preprints (earlier versions) of this paper are available at, first published .
Guided Internet-Based Cognitive Behavioral Therapy for Women With Bulimia Nervosa: Protocol for a Multicenter Randomized Controlled Trial

Guided Internet-Based Cognitive Behavioral Therapy for Women With Bulimia Nervosa: Protocol for a Multicenter Randomized Controlled Trial

Guided Internet-Based Cognitive Behavioral Therapy for Women With Bulimia Nervosa: Protocol for a Multicenter Randomized Controlled Trial


1Research Center for Child Mental Development, University of Fukui, Fukui, Japan

2Division of Developmental Higher Brain Functions, United Graduate School of Child Development, University of Fukui, Fukui, Japan

3Department of Child and Adolescent Psychological Medicine, University of Fukui Hospital, Fukui, Japan

4Division of Clinical Psychology, Kagoshima University Hospital, Kagishima, Japan

5Department of Behavioural Sciences and Learning, Linköping University, Linköping, Sweden

6Department of Biomedical and Clinical Science, Linköping University, Linköping, Sweden

7Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden

8Department of Psychiatry, Graduate School of Biomedical Sciences, Tokushima University, Tokushima, Japan

9Research Center for Child Mental Development, Chiba University, Chiba, Japan

10Department of Behavioral Medicine, National Institute of Mental Health, National Center of Neurology and Psychiatry, Tokyo, Japan

11Department of Psychosomatic Medicine, Tohoku University Hospital, Sendai, Japan

12Department of Psychiatry, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan

13Child Development and Psychosomatic Medicine Center, Dokkyo Medical University Saitama Medical Center, Saitama, Japan

14Department of Neuropsychiatry, University of Fukui, Fukui, Japan

Corresponding Author:

Sayo Hamatani, PhD

Research Center for Child Mental Development

University of Fukui

23-3 Matsuoka Shimoaizuki, Eiheiji-cho, Yoshida-gun

Fukui, 910-1193


Phone: 81 776 61 3111


Background: Individual face-to-face cognitive behavioral therapy is known to be effective for bulimia nervosa (BN). Since foods vary considerably between regions and cultures in which patients live, cultural adaptation of the treatment program is particularly important in cognitive behavioral therapy for BN. Recently, an internet-based cognitive behavioral therapy (ICBT) program was developed for Japanese women with BN, adapted to the Japanese food culture. However, no previous randomized controlled trial has examined the effectiveness of ICBT.

Objective: This paper presents a research protocol for strategies to examine the effects of guided ICBT.

Methods: This study is designed as a multicenter, prospective, assessor-blinded randomized controlled trial. The treatment groups will be divided into treatment as usual (TAU) alone as the control group and ICBT combined with TAU as the intervention group. The primary outcome is the total of binge eating and purging behaviors assessed before and after treatment by an independent assessor. Secondary outcomes will include measures of eating disorder severity, depression, anxiety, quality of life, treatment satisfaction, and working alliances. Treatment satisfaction and working alliances will be measured post assessment only. Other measures will be assessed at baseline, post intervention, and follow-up, and the outcomes will be analyzed on an intention-to-treat basis.

Results: This study will be conducted at 7 different medical institutions in Japan from August 2022 to October 2026. Recruitment of participants began on August 19, 2022, and recruitment is scheduled to continue until July 2024. The first participants were registered on September 8, 2022.

Conclusions: This is the first multicenter randomized controlled trial in Japan comparing the effectiveness of ICBT and TAU in patients with BN.

Trial Registration: University Hospital Medical Information Network UMIN000048732;

International Registered Report Identifier (IRRID): DERR1-10.2196/49828

JMIR Res Protoc 2023;12:e49828




Bulimia nervosa (BN) is an eating disorder characterized by binge eating, purging or fasting, and concerns associated with body shape and weight [1]. Patients with BN often have a distorted body image despite being at standard levels with regard to shape and weight [2]. Consequently, they perform frequent purging or fasting or excessive exercise on the basis of a subjectively abnormal perception of their body shape and weight [3]. Body image distortion involves perceptual disturbances and body dissatisfaction [4]. Repeated episodes of binge eating and inappropriate compensatory behaviors can cause serious physical and mental health concerns. Vomiting after overeating may result in thickened skin on the knuckles, broken teeth, and thyroid dysfunction due to problems with metabolic rate and caloric intake [5,6]. In terms of mental health, patients with BN frequently show low self-esteem, self-harming behaviors, suicidal tendencies, depression, anxiety disorders, sleep disorders, and fatigue or exhaustion [7-12].

Prevalence of BN and Accessibility to the Treatment

Epidemiological studies confirm that eating disorders are highly prevalent, particularly among women: 2.58% of women in Western countries [13]. The overall observed prevalence of eating disorders was 3.5% between 2000 and 2006 and increased to 7.8% between 2013 and 2018 [14]. A recent meta-analysis estimated that the lifetime and 12-month prevalence of eating disorders was 0.91% and 0.43%, respectively, while the lifetime prevalence of BN was 0.63% [13]. Face-to-face cognitive behavioral therapy (CBT) has been shown to be effective for eating disorders [15], but poor access to treatment remains a problem [16]. In fact, only 19%-36% of people with eating disorders have access to treatment within 1 year [17-19], and 35%-40% of these patients receive standard treatment for eating disorders [20,21]. Furthermore, treatment for eating disorders is sought an average of 5-15 years after the onset of the disorder [16,22]. Access to these appropriate treatments is often hampered by physical barriers, lack of practitioners, and stigma. These problems are particularly associated with face-to-face delivery. Web-mediated interventions may be effective in initiating appropriate early treatment [23,24]. CBT via the internet can dramatically improve access to treatment, especially in developed countries, in which the internet infrastructure is well-developed and information communication devices are widely used.

A New CBT Model for BN

Enhanced CBT has been shown to be effective in treating eating disorders, including BN. Enhanced CBT encourages the early establishment of healthy and safe eating habits and facilitates behavioral changes and cognitive modification through psychoeducation and self-monitoring. In addition, accumulating evidence from many clinical studies is being integrated to establish CBT techniques that have shown promise for the treatment of eating disorders. In a network analysis, fear of weight gain was suggested to be central to the psychopathology of BN, and hypersensitivity to physical sensations was shown to bridge BN with anxiety or depression [25]. Based on the evidence, this network meta-analysis argued that focusing on the fear of weight gain during exposure therapy and interventions focused on interoceptive exposure is effective in treating BN. However, several other CBTs may also be effective in treating BN, including attentional bias correction training to correct the direction of excessive attention to the body, weight, and food [26], relaxation, and mindfulness to reduce physiological responses such as anxiety and tension [27], traumatic memory care for experiences of being criticized for one’s body type and appearance [28], and impulse control, such as cue exposure [29]. A therapist’s manual for CBT of BN that systematically summarizes these CBT components has been published by Hamatani and Matsumoto [30]. Our research group recently developed a web-based program based on this CBT therapist’s manual by checking the cultural adaptability in Japan [31].


As mentioned earlier, we developed an internet-based cognitive behavioral therapy (ICBT) program for BN that is adapted to Japanese culture and based on Japanese food culture [30,31]. This paper describes the study protocol for a randomized controlled trial (RCT) involving female patients with BN and is designed to evaluate its clinical effects. We will include an intervention group receiving ICBT in addition to treatment as usual (TAU) and a control group receiving TAU alone.

Study Design

This study is designed as a multicenter, prospective, randomized, assessor-blinded clinical trial. The RCT and follow-up study are planned from August 2022 to October 2026 (UMIN000048732). It will be conducted at the following 7 institutions (6 university hospitals and a national medical center) in Japan: University of Fukui Hospital, Kagoshima University Hospital, Chiba University Hospital, Tokushima University Hospital, Dokkyo Medical University, Tohoku University Hospital, and National Center for Neurology and Psychiatry.

Participants and Eligibility Criteria

Eligible participants will be women aged 13-65 years (1) diagnosed with BN according to the Diagnostic and Statistical Manual of Mental Disorders criteria during a clinical interview [1]; (2) having a BMI over 17.5 kg/m2; (3) using computers, tablets, smartphones, etc, on a daily basis, with access to the internet and the minimum necessary information and communications technology skills; and (4) with no history of CBT in the last 2 years. Exclusion criteria include (1) serious mental disorders such as organic brain disorders, psychotic disorders, and drug dependence; (2) imminent risk of suicide; (3) repeated engagement in antisocial behavior; (4) serious progressive physical disease; and (5) difficulty in exposure to feared objects due to severe stress reactions or dissociation symptoms due to acute stress disorder or posttraumatic stress disorder. The purpose of the study is to investigate the effects of an ICBT program that has been adapted based on the culture of Japanese women. Men and women differ in their caloric needs, and most studies regarding eating disorders include female patients. This intervention program is based on the findings of previous studies; therefore, only women will be recruited. In addition, information and communication technology literacy varies considerably by patient age in Japan, with older adults having lower information and communication technology literacy. The intervention in this study is mainly self-help CBT using a web-based platform. Therefore, patients aged 65 years and older will be excluded from the study.


From August 2022 to July 2024, we will recruit 60 out-participants with female BN through posters, flyers, web or app advertisements (Google Ads, Twitter, and Facebook), newspaper advertisements, etc, posted at medical institutions throughout Japan. Since all participants will continue to be treated, they will be required to obtain clearance from their primary care physician prior to their study enrollment. The participants pay for TAU, but guided ICBT is free. Participants will be rewarded US $82.51 after intervention or waiting completion, regardless of group allocation. These include the amount of time patients spent on the trial and the difficulty of recruiting patients. To participate in this study, some hospitals will require referrals, which may cost the participant money.


Participants will be directed to a website for this study by the various media mentioned earlier. There they will access the study website to apply for enrollment in the study. The clinical trial office at the University of Fukui that receives this application will coordinate the informed consent and eligibility test. Written informed consent will be solicited after the participants are provided research briefing either face-to-face or in a video call. Similarly, in the case of a minor, written informed consent from a legal representative is required. Next, they will complete a screening survey and a structured interview using Mini International Neuropsychiatric Interview version 5 [32,33]. Finally, they will be asked to complete a baseline data questionnaire on the web. The decision regarding the participant’s exclusion or inclusion in the study will be made after they have completed the questionnaire. See Figure 1 for the flow of participants in this RCT.

Figure 1. Flowchart of the recruitment and assessments during this study. ICBT: internet-based cognitive behavioral therapy.


Guided ICBT Program

This ICBT program is based on the treatment manual for BN in Japanese [30]. The ICBT program consists of 1 assessment module and 12 treatment modules, each dedicated to one theme, along with reporting of the development process [31]. Each module includes psychoeducation and practice exercises on CBTs. Each module begins with a video containing complex supporting explanations and messages of encouragement (see Table 1 for details). A secure web-based platform [34] will be used for communication between therapists and participants, distribution of program materials, and collection of assessments. At the start of the intervention, participants will receive an email containing their username and a link to create their own password so that they can log into the platform. Participants will be provided access to 1 new module each week for the duration of the 12-week intervention, starting with module 1. For the first week, an assessment module (module 0) will be provided together with module 1. Once accessible, the modules will be available throughout the treatment duration. Participants who have not viewed the material or practiced it for a particular week will be sent a reminder once a week. If they have any questions, they can contact their therapists via the secure messaging feature on the platform. The therapist is a well-trained and experienced cognitive behavioral therapist (SH). The therapist will receive supervision from KM on the treatment of BN.

Table 1. The internet-based cognitive behavioral therapy modules in the randomized controlled trial.

0Assessment and goal-settingFirst, a description of how to use the program and how the program is structured. Data on the user’s basic clinical background, family composition, and chief complaint are collected. Then, treatment goals are set at the end.
1Psychoeducation and cognitive behavioral modelAn overview of the DSM-5a diagnostic classification [1] is provided and the epidemiological features of BNb [35]. Psychoeducation about CBTc for BN is introduced. Perceptions, attention, images, emotions, memories, thoughts, and the vicious circles of habitual behaviors are created graphically [30].
2Relaxation and mindfulness medicationAn introduction to the autonomic nervous system and training in breathing techniques, progressive muscle relaxation, and mindfulness meditation are provided [27,29].
3Metacognitive trainingMetacognition, one of the cognitive functions, is vulnerable in eating disorders [36], and there is evidence that cognitive weakness affects QOLd [37]. Metacognitive interventions may improve eating disorder severity, depression, and QOL [24,38]. This involves dichotomous thinking, emotional judgment, jumping to conclusions, and perfectionism, among others [30,31].
4Attention bias modification and modification of interpretation for appearancePeople with eating disorders tend to focus on body shape, weight, and food overload [39,40]. Exercises are provided that shift attention from food stimuli to neutral stimuli [41,42]. People with eating disorders frequently rate their body shape and weight negatively [43]. When recognizing the threatening bias of one’s natural body shape and weight, the client can use techniques of relaxation and metacognition to handle concerns about perceived body shape and weight.
5Behavioral experiment for binge eatingBehavioral experiments will be used to see that eating does not lead to uncontrolled weight gain [44].
6Management of healthy food contents and eating habitsSelf-monitoring using food diaries reduces the frequency of binge eating in web-based programs [45]. We propose a Japanese food menu to achieve a well-balanced diet [31]. This approach was developed based on a nutritional rehabilitation called “mechanical diet” by Garner et al [46].
7Creating an anxiety hierarchy chart and stepwise exposureAddressing fears associated with overeating can reduce overeating in BN [47,48].
8Exposure to cues preceding binge eating and purgingTriggers for overeating and purging vary from person to person; however, exposure to such cues can reduce overeating and purging [29].
9Cognitive restructuringNegative self-statements associated with eating disorders are frequently observed in BN [49]. Such self-assertions shape the person’s own identity and values [50]. Cognitive restructuring fosters alternative ways of thinking about these self-statements (adaptive thinking).
10Rewriting of traumatic memory for image of the bodyThere are often individuals with BN who have negative childhood experiences [51]. If the interpretation of a traumatic memory is tormenting the patient, it should be rewritten to make it safer.
11Schema workRescripting dysfunctional beliefs (schemas) may reduce the frequency of binge eating and purging as well as body shape concerns [52]. Dysfunctional beliefs are organized and alternative beliefs are written down.
12Prevention of relapseA summary of what participants have learned from the treatment will be solicited and used to plan future efforts to further reduce symptoms and prevent relapse.

aDSM-5: Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition.

bBN: bulimia nervosa.

cCBT: cognitive behavioral therapy.

dQOL: quality of life.

TAU (Control Group)

Participants will be allowed to continue receiving counseling, psychotropics, and other medications for the duration of the study. No new drug therapy or additional changes will be recommended during the study period by the study staff. However, the participant’s primary care physician will not be prevented from modifying medications and refer participants to counseling or second-line therapy if deemed clinically appropriate. All changes in TAU will be documented along with the reasons for these changes. Participants in the control group (TAU) will be offered ICBT after a waiting period as well.


Demographic Data

Participants will be asked about age, educational level, marital status, employment status, BMI, age at BN onset, duration of BN, comorbidities, and the presence or absence of psychotropic or antidepressant drug use.

Primary Outcome

The primary outcome will be the weekly combined frequency of binge eating and purging behaviors. These will be measured by an independent assessor whose allocations are masked.

Secondary Outcomes

Secondary self-reported outcomes will be the Eating Disorders Examination Questionnaire [53,54], Patient Health Questionnaire-9 [55,56], Generalized Anxiety Disorder Scale-7 [56,57], EQ-5D [58,59], Brunnsviken Brief Quality of Life Scale [60] at baseline, postintervention, and follow-up (1-, 3-, 6-, 9-, and 21-month follow-ups). Assessments based on the Working Alliance Inventory-Short Form [61] and Client Satisfaction Questionnaire [62,63] will be performed only after the treatment.

Sample Size

The required sample size was calculated using statistical analysis software (G*Power, version 3.1; Heinrich-Heine-Universitaet Duesseldorf). An effect size of Cohen d=0.90 from a previous study was used as a reference [64]. The significance level was set at P values <.05 for 2-sided tests. The power was set to 80%. The required sample size (assigned number of participants) will be 60 when considering a 30% noncompletion rate based on a previous study [65]. Completers in this study are defined as those who complete at least 80% of the module [65]. In addition, dropouts in this study are defined as those who drop out by not providing postevaluation data or those who discontinue their participation due to adverse events.


Participants confirmed to be eligible and enrolled will be randomized in a 1:1 ratio to either the intervention (TAU added guided ICBT) or TAU alone groups by the truncated binomial design using UMIN’s (University Hospital Medical Information Network) computer program (UMIN Center). The truncated binomial design is that complete randomization will be performed until the number of randomizations to any group reaches n/2, after which all subjects are allocated to the other group to prevent an imbalance in the number of people.

Statistical Analysis Plan

Statistical analysis will be performed using SPSS Statistics software (version 29; IBM Corp). Statistical analysis will be performed in accordance with the CONSORT (Consolidated Standards of Reporting Trials) guidelines and based on the intention-to-treat principle (Multimedia Appendix 1). Missing data will be handled by multiple imputations. Unpaired t test and Fisher exact test will be used to investigate the difference between the 2 groups at baseline. To compare treatment effects, we will use analysis of covariance for primary and all secondary outcomes. As a covariate, we plan to include a scale that is significantly different between the 2 groups at baseline. We also will perform a per-protocol analysis by excluding patients who deviate from the protocol. Analysis of covariance will also be performed on the follow-up data. However, if there are many missing values, we would consider generalized linear mixed models. All P values are 2-tailed, and P values <.05 will be considered statistically significant.

Ethical Considerations

The clinical trial protocol was approved by the Research Ethics Committee of the University of Fukui on August 15, 2022 (20220054), and was registered in the UMIN Domestic Clinical Trial Database (UMIN000048732). Each participant will then be informed that all participants will receive TAU from the general practitioner and that half of the participants will receive ICBT in addition to TAU. All adverse events will be reported, and serious adverse events will be reported immediately to the institutional review board. An adverse event is defined as any symptom or illness occurring during a clinical trial, whether related to the ICBT program or not. The results of the trial will be published in the appropriate journal, regardless of the outcomes. The trial will be implemented and reported in accordance with the CONSORT recommendations.

Recruitment began on August 19, 2022, following the attainment of ethics approval on August 15, 2022, and the granting of permission to conduct the study on August 18, 2022. The first participant was enrolled on September 8, 2022, and recruitment is scheduled until July 2024. First, we plan to report the results using pre-post data from the RCT design. Subsequently, we will also report the 2-year long-term effects of those who received ICBT.

Anticipated Findings

This paper presents the research protocol for the first RCT designed to investigate the effectiveness of therapist-guided ICBT for female Japanese patients with BN. Notably, a recent RCT demonstrated the efficacy of ICBT for binge eating disorder and other specified feeding or eating disorders [66]. However, although that study, conducted in the Netherlands, showed promising results for guided ICBT in these eating disorders, it involved participants with varying BMI of 19.5 or 40.0 kg/m2 and did not include patients specifically diagnosed with BN. In contrast, this study protocol uses specific eligibility criteria, focusing solely on individuals with BN as the primary diagnosis while excluding other eating disorders, such as binge eating disorder. Consequently, the patient cohort to be included in our RCT is anticipated to be homogenous, thereby bolstering confidence in the treatment’s effectiveness. Meanwhile, a systematic review and meta-analysis examining e-therapy’s impact on eating disorders reported inconclusive evidence regarding the effect on overeating frequency in patients with BN [67]. Although this meta-analysis found improvements in various aspects, such as binge eating, vomiting, and laxative misuse, and in the discontinuation rate of overeating symptoms at the intervention’s conclusion, the estimates were imprecise due to the heterogeneity in the quality of studies included in the analysis. Therefore, the authors concluded that e-therapy, including guided ICBT, could be effective for the management of eating disorders; however, further research is needed. A recent single-arm ICBT study targeting patients with eating disorders, including BN, reported positive outcomes [65]. In evidence-based medicine, individual RCT holds the highest level of evidence among single clinical trials [68]. Nevertheless, the outcomes of single-arm clinical trials lacking a control group should be interpreted with caution. In this context, our RCT may expand the understanding of the efficacy of guided ICBT for BN. To our knowledge, even recent RCTs have not provided effect estimates for patients with BN alone, as they also included other eating disorders [69,70]. Therefore, this study, by adhering closely to the RCT protocol described herein, will be well-positioned to offer valuable insights into the efficacy of guided ICBT on the frequency of overeating and purging along with any secondary symptoms in patients with BN. Furthermore, to the best of our knowledge, this is the first study designed to examine the effects of ICBT on behavioral changes related to eating styles in Japan. This is especially significant given Japan’s distinct food culture and medical system that sets it apart from Western countries. The investigation into the effects of ICBT for BN within the context of Japan carries particular importance, as it navigates cultural nuances and differences in the medical system. Therefore, a multicenter study design is more likely to reduce bias and yield findings with broader generalizability.


One limitation of the study is that it would not allow elucidation of the specific effects of the ICBT program because it does not use a psychological placebo group to control for nonspecific factors.


This RCT aims to validate and prove evidence for the efficacy of a Japanese culture–adapted ICBT program for female patients with BN. This will allow discussion of efficacy beyond the preliminary results obtained to date. The low availability of CBT is an international problem, and the implementation rate of CBT in Japanese psychiatric clinics is extremely low at 6.2% [71]. If positive results are obtained from this RCT, more patients with BN could receive early treatment, which could lead to early improvement in eating disorders that tend to be prolonged and chronic.


We would like to express our utmost gratitude to George Vlaescu for his role as webmaster. This work is supported by the Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (grant JP22H00985), Lotte Research Promotion Grant, and the Collaborative Research Program of the Collaborative Research Network for Asian Children With Developmental Disorders: MEXT Policy Initiative FY2022, under joint research conducted through the initiative.

Data Availability

Data sharing is not applicable to this paper as no data sets were generated or analyzed during this study.

Authors' Contributions

SH initiated the project, planned the research, obtained funding, and wrote the paper. KM, YH, HK, and YM are funded research collaborators who contributed significantly to the study conception or design. GA participated in data management and write-up of the report. YT, SN, RK, AS, YS, SF, NS, MN, RO, and RS contributed significantly at the various stages of research and development toward practical implementation. YM oversaw the overall conduct of the study. All authors read, critically revised, and approved the final paper.

Conflicts of Interest

None declared.

Multimedia Appendix 1

CONSORT-eHEALTH checklist.

DOCX File , 23 KB

  1. Diagnostic and Statistical Manual of Mental Disorders, 5th Edition. (DSM-5). Washington, DC. American Psychiatric Association; 2014.
  2. Flett GL, Newby J, Hewitt PL, Persaud C. Perfectionistic automatic thoughts, trait perfectionism, and bulimic automatic thoughts in young women. J Rat-Emo Cognitive-Behav Ther. 2011;29(3):192-206. [CrossRef]
  3. Kaye W. Neurobiology of anorexia and bulimia nervosa. Physiol Behav. Apr 22, 2008;94(1):121-135. [FREE Full text] [CrossRef] [Medline]
  4. Yamamotova A, Bulant J, Bocek V, Papezova H. Dissatisfaction with own body makes patients with eating disorders more sensitive to pain. J Pain Res. 2017;10(3):1667-1675. [FREE Full text] [CrossRef] [Medline]
  5. Spalter AR, Gwirtsman HE, Demitrack MA, Gold PW. Thyroid function in bulimia nervosa. Biol Psychiatry. 1993;33(6):408-414. [FREE Full text] [CrossRef] [Medline]
  6. Strumia R. Eating disorders and the skin. Clin Dermatol. 2013;31(1):80-85. [FREE Full text] [CrossRef] [Medline]
  7. Allison KC, Spaeth A, Hopkins CM. Sleep and eating disorders. Curr Psychiatry Rep. 2016;18(10):92. [FREE Full text] [CrossRef] [Medline]
  8. Anderson CB, Carter FA, McIntosh VV, Joyce PR, Bulik CM. Self-harm and suicide attempts in individuals with bulimia nervosa. Eat Disord. 2002;10(3):227-243. [CrossRef] [Medline]
  9. de Vos JA, Radstaak M, Bohlmeijer ET, Westerhof GJ. Having an eating disorder and still being able to flourish? Examination of pathological symptoms and well-being as two continua of mental health in a clinical sample. Front Psychol. 2018;9:2145. [FREE Full text] [CrossRef] [Medline]
  10. Garcia SC, Mikhail ME, Keel PK, Burt SA, Neale MC, Boker S, et al. Increased rates of eating disorders and their symptoms in women with major depressive disorder and anxiety disorders. Int J Eat Disord. 2020;53(11):1844-1854. [FREE Full text] [CrossRef] [Medline]
  11. Sagiv E, Gvion Y. A multi factorial model of self-harm behaviors in anorexia-nervosa and bulimia-nervosa. Compr Psychiatry. 2020;96:152142. [FREE Full text] [CrossRef] [Medline]
  12. Ulfvebrand S, Birgegård A, Norring C, Högdahl L, von Hausswolff-Juhlin Y. Psychiatric comorbidity in women and men with eating disorders results from a large clinical database. Psychiatry Res. 2015;230(2):294-299. [FREE Full text] [CrossRef] [Medline]
  13. Qian J, Wu Y, Liu F, Zhu Y, Jin H, Zhang H, et al. An update on the prevalence of eating disorders in the general population: a systematic review and meta-analysis. Eat Weight Disord. 2022;27(2):415-428. [FREE Full text] [CrossRef] [Medline]
  14. Galmiche M, Déchelotte P, Lambert G, Tavolacci MP. Prevalence of eating disorders over the 2000-2018 period: a systematic literature review. Am J Clin Nutr. 2019;109(5):1402-1413. [FREE Full text] [CrossRef] [Medline]
  15. Linardon J, Wade TD, de la Piedad Garcia X, Brennan L. The efficacy of cognitive-behavioral therapy for eating disorders: a systematic review and meta-analysis. J Consult Clin Psychol. 2017;85(11):1080-1094. [CrossRef] [Medline]
  16. Hamilton A, Mitchison D, Basten C, Byrne S, Goldstein M, Hay P, et al. Understanding treatment delay: perceived barriers preventing treatment-seeking for eating disorders. Aust N Z J Psychiatry. 2022;56(3):248-259. [CrossRef] [Medline]
  17. Cachelin FM, Striegel-Moore RH. Help seeking and barriers to treatment in a community sample of Mexican American and European American women with eating disorders. Int J Eat Disord. 2006;39(2):154-161. [FREE Full text] [CrossRef] [Medline]
  18. Vanheusden K, Mulder CL, van der Ende J, van Lenthe FJ, Mackenbach JP, Verhulst FC. Young adults face major barriers to seeking help from mental health services. Patient Educ Couns. 2008;73(1):97-104. [FREE Full text] [CrossRef] [Medline]
  19. Hart LM, Granillo MT, Jorm AF, Paxton SJ. Unmet need for treatment in the eating disorders: a systematic review of eating disorder specific treatment seeking among community cases. Clin Psychol Rev. 2011;31(5):727-735. [CrossRef] [Medline]
  20. Mond JM, Hay PJ, Rodgers B, Owen C. Health service utilization for eating disorders: findings from a community-based study. Int J Eat Disord. 2007;40(5):399-408. [CrossRef] [Medline]
  21. Noordenbos G, Oldenhave A, Muschter J, Terpstra N. Characteristics and treatment of patients with chronic eating disorders. Eat Disord. 2002;10(1):15-29. [CrossRef] [Medline]
  22. Browne MAO, Wells JE, McGee MA, New Zealand Mental Health Survey Research Team. Twelve-month and lifetime health service use in Te Rau Hinengaro: the New Zealand mental health survey. Aust N Z J Psychiatry. 2006;40(10):855-864. [CrossRef] [Medline]
  23. Andersson G, Cuijpers P, Carlbring P, Riper H, Hedman E. Guided internet-based vs. face-to-face cognitive behavior therapy for psychiatric and somatic disorders: a systematic review and meta-analysis. World Psychiatry. 2014;13(3):288-295. [FREE Full text] [CrossRef] [Medline]
  24. Hamatani S, Matsumoto K, Takahashi J, Shiko Y, Ozawa Y, Niitsu T, et al. Feasibility of guided internet-based cognitive behavioral therapy for patients with anorexia nervosa. Internet Interv. 2022;27:100504. [FREE Full text] [CrossRef] [Medline]
  25. Levinson CA, Zerwas S, Calebs B, Forbush K, Kordy H, Watson H, et al. The core symptoms of bulimia nervosa, anxiety, and depression: a network analysis. J Abnorm Psychol. 2017;126(3):340-354. [FREE Full text] [CrossRef] [Medline]
  26. Boutelle KN, Monreal T, Strong DR, Amir N. An open trial evaluating an attention bias modification program for overweight adults who binge eat. J Behav Ther Exp Psychiatry. 2016;52:138-146. [FREE Full text] [CrossRef] [Medline]
  27. Godfrey KM, Gallo LC, Afari N. Mindfulness-based interventions for binge eating: a systematic review and meta-analysis. J Behav Med. 2015;38(2):348-362. [CrossRef] [Medline]
  28. Mitchell KS, Mazzeo SE, Schlesinger MR, Brewerton TD, Smith BN. Comorbidity of partial and subthreshold PTSD among men and women with eating disorders in the national comorbidity survey-replication study. Int J Eat Disord. 2012;45(3):307-315. [FREE Full text] [CrossRef] [Medline]
  29. McIntosh VVW, Carter FA, Bulik CM, Frampton CMA, Joyce PR. Five-year outcome of cognitive behavioral therapy and exposure with response prevention for bulimia nervosa. Psychol Med. 2011;41(5):1061-1071. [FREE Full text] [CrossRef] [Medline]
  30. Hamatani S, Matsumoto K. A manual of cognitive behavioral therapy of bulimia nervosa for therapists. HOPE Project. URL: [accessed 2023-01-22]
  31. Hamatani S, Matsumoto K, Ishibashi T, Shibukawa R, Honda Y, Kosaka H, et al. Development of a culturally adaptable internet-based cognitive behavioral therapy for Japanese women with bulimia nervosa. Front Psychiatry. 2022;13:942936. [FREE Full text] [CrossRef] [Medline]
  32. Sheehan DV, Lecrubier Y, Sheehan KH, Amorim P, Janavs J, Weiller E, et al. The Mini-International Neuropsychiatric Interview (M.I.N.I.): the development and validation of a structured diagnostic psychiatric interview for DSM-IV and ICD-10. J Clin Psychiatry. 1998;59(Suppl 20):22-33. [Medline]
  33. Muramatsu K, Miyaoka H, Kamijima K, Muramatsu Y, Yoshida M, Otsubo T, et al. The patient health questionnaire, Japanese version: validity according to the mini-international neuropsychiatric interview-plus. Psychol Rep. 2007;101(3):952-960. [CrossRef] [Medline]
  34. Vlaescu G, Alasjö A, Miloff A, Carlbring P, Andersson G. Features and functionality of the Iterapi platform for internet-based psychological treatment. Internet Interv. 2016;6:107-114. [FREE Full text] [CrossRef] [Medline]
  35. Kessler RC, Berglund PA, Chiu WT, Deitz AC, Hudson JI, Shahly V, et al. The prevalence and correlates of binge eating disorder in the World Health Organization world mental health surveys. Biol Psychiatry. 2013;73(9):904-914. [FREE Full text] [CrossRef] [Medline]
  36. Hamatani S, Tomotake M, Takeda T, Kameoka N, Kawabata M, Kubo H, et al. Impaired social cognition in anorexia nervosa patients. Neuropsychiatr Dis Treat. 2016;12:2527-2531. [FREE Full text] [CrossRef] [Medline]
  37. Hamatani S, Tomotake M, Takeda T, Kameoka N, Kawabata M, Kubo H, et al. Influence of cognitive function on quality of life in anorexia nervosa patients. Psychiatry Clin Neurosci. 2017;71(5):328-335. [FREE Full text] [CrossRef] [Medline]
  38. Jelinek L, Faissner M, Moritz S, Kriston L. Long-term efficacy of Metacognitive Training for Depression (D-MCT): a randomized controlled trial. Br J Clin Psychol. 2019;58(3):245-259. [FREE Full text] [CrossRef] [Medline]
  39. Davis CA, Levitan RD, Reid C, Carter JC, Kaplan AS, Patte KA, et al. Dopamine for "wanting" and opioids for "liking": a comparison of obese adults with and without binge eating. Obesity (Silver Spring). 2009;17(6):1220-1225. [FREE Full text] [CrossRef] [Medline]
  40. Nijs IMT, Franken IHA. Attentional processing of food cues in overweight and obese individuals. Curr Obes Rep. 2012;1(2):106-113. [FREE Full text] [CrossRef] [Medline]
  41. MacLeod C, Clarke PJF. The attentional bias modification approach to anxiety intervention. Clin Psychol Sci. 2015;3(1):58-78. [CrossRef]
  42. Kuckertz JM, Amir N. Attention bias modification for anxiety and phobias: current status and future directions. Curr Psychiatry Rep. 2015;17(2):9. [FREE Full text] [CrossRef] [Medline]
  43. Anitha L, Alhussaini AA, Alsuwedan HI. Bulimia nervosa and body dissatisfaction in terms of self-perception of body image. In: Himmerich H, Lobera IJ, editors. Psychology, Medicine, Anorexia and Bulimia Nervosa. Online. IntechOpen; 2019.
  44. Waller G, Mountford VA. Weighing patients within cognitive-behavioural therapy for eating disorders: how, when and why. Behav Res Ther. 2015;70:1-10. [FREE Full text] [CrossRef] [Medline]
  45. Barakat S, Maguire S, Surgenor L, Donnelly B, Miceska B, Fromholtz K, et al. The role of regular eating and self-monitoring in the treatment of bulimia nervosa: a pilot study of an online guided self-help CBT program. Behav Sci (Basel). 2017;7(3):39. [FREE Full text] [CrossRef] [Medline]
  46. Garner DM, Desai JJ, Desmond M, Wohlers J. Nutritional rehabilitation for eating disorders: river centre clinic program description. Annal Nutr Disord Ther. 2017;4(2):1044. [FREE Full text] [CrossRef]
  47. Cooper PJ, Steere J. A comparison of two psychological treatments for bulimia nervosa: implications for models of maintenance. Behav Res Ther. 1995;33(8):875-885. [FREE Full text] [CrossRef] [Medline]
  48. Rosen JC, Leitenberg H. Bulimia nervosa: treatment with exposure and response prevention. Behav Ther. 1982;13(1):117-124. [FREE Full text] [CrossRef]
  49. Scott N, Hanstock TL, Thornton C. Dysfunctional self-talk associated with eating disorder severity and symptomatology. J Eat Disord. 2014;2(1):14. [FREE Full text] [CrossRef] [Medline]
  50. Higbed L, Fox JRE. Illness perceptions in anorexia nervosa: a qualitative investigation. Br J Clin Psychol. 2010;49(3):307-325. [FREE Full text] [CrossRef] [Medline]
  51. Hicks White AA, Pratt KJ, Cottrill C. The relationship between trauma and weight status among adolescents in eating disorder treatment. Appetite. 2018;129:62-69. [CrossRef] [Medline]
  52. McIntosh VVW, Jordan J, Carter JD, Frampton CMA, McKenzie JM, Latner JD, et al. Psychotherapy for transdiagnostic binge eating: a randomized controlled trial of cognitive-behavioural therapy, appetite-focused cognitive-behavioural therapy, and schema therapy. Psychiatry Res. 2016;240:412-420. [FREE Full text] [CrossRef] [Medline]
  53. Mitsui T, Yoshida T, Komaki G. Psychometric properties of the eating disorder examination-questionnaire in Japanese adolescents. Biopsychosoc Med. 2017;11(10):9-792. [FREE Full text] [CrossRef] [Medline]
  54. Fairburn CG, Beglin SJ. Assessment of eating disorders: interview or self-report questionnaire? Int J Eat Disord. 1994;16(4):363-370. [FREE Full text] [CrossRef]
  55. Spitzer RL, Kroenke K, Williams JB. Validation and utility of a self-report version of PRIME-MD: the PHQ primary care study. Primary care evaluation of mental disorders. Patient health questionnaire. JAMA. 1999;282(18):1737-1744. [FREE Full text] [CrossRef] [Medline]
  56. Muramatsu K. Patient Health Questionnaire (PHQ-9, PHQ-15). Japanese version and generalized anxiety disorder-7 up to date. Stud Clin Psychol. 2014;7:35-39.
  57. Spitzer RL, Kroenke K, Williams JBW, Löwe B. A brief measure for assessing generalized anxiety disorder: the GAD-7. Arch Intern Med. 2006;166(10):1092-1097. [FREE Full text] [CrossRef] [Medline]
  58. Tsuchiya A, Ikeda S, Ikegami N, Nishimura S, Sakai I, Fukuda T, et al. Estimating an EQ-5D population value set: the case of Japan. Health Econ. 2002;11(4):341-353. [FREE Full text] [CrossRef] [Medline]
  59. EuroQol Group. EuroQol—a new facility for the measurement of health-related quality of life. Health Policy. 1990;16(3):199-208. [FREE Full text] [CrossRef] [Medline]
  60. Lindner P, Frykheden O, Forsström D, Andersson E, Ljótsson B, Hedman E, et al. The Brunnsviken Brief Quality of Life Scale (BBQ): development and psychometric evaluation. Cogn Behav Ther. 2016;45(3):182-195. [FREE Full text] [CrossRef] [Medline]
  61. Tracey TJ, Kokotovic AM. Factor structure of the Working Alliance Inventory. Psychol Assess: J Consult Clin Psychol. 1989;1(3):207-210. [CrossRef]
  62. Attkisson CC, Zwick R. The client satisfaction questionnaire. Psychometric properties and correlations with service utilization and psychotherapy outcome. Eval Program Plann. 1982;5(3):233-237. [FREE Full text] [CrossRef] [Medline]
  63. Tachimori H, Ito H. Nihonngobann client satisfaction questionnaire 8 koumokubann no shinnraisei oyobi datousei no kenntou [Reliability and validity of the Japanese version of client satisfaction questionnaire]. Seishin Igaku. 1999;41(7):711-717. [FREE Full text] [CrossRef]
  64. Ruwaard J, Lange A, Broeksteeg J, Renteria-Agirre A, Schrieken B, Dolan CV, et al. Online cognitive-behavioural treatment of bulimic symptoms: a randomized controlled trial. Clin Psychol Psychother. 2013;20(4):308-318. [FREE Full text] [CrossRef] [Medline]
  65. Wiberg AC, Ghaderi A, Danielsson HB, Safarzadeh K, Parling T, Carlbring P, et al. Internet-based cognitive behavior therapy for eating disorders—development and feasibility evaluation. Internet Interv. 2022;30:100570. [FREE Full text] [CrossRef] [Medline]
  66. Melisse B, van den Berg E, de Jonge M, Blankers M, van Furth E, Dekker J, et al. Efficacy of web-based, guided self-help cognitive behavioral therapy-enhanced for binge eating disorder: randomized controlled trial. J Med Internet Res. 2023;25:e40472. [FREE Full text] [CrossRef] [Medline]
  67. Loucas CE, Fairburn CG, Whittington C, Pennant ME, Stockton S, Kendall T. E-therapy in the treatment and prevention of eating disorders: a systematic review and meta-analysis. Behav Res Ther. 2014;63:122-131. [FREE Full text] [CrossRef] [Medline]
  68. Burns PB, Rohrich RJ, Chung KC. The levels of evidence and their role in evidence-based medicine. Plast Reconstr Surg. 2011;128(1):305-310. [FREE Full text] [CrossRef] [Medline]
  69. Strandskov SW, Ghaderi A, Andersson H, Parmskog N, Hjort E, Wärn AS, et al. Effects of tailored and ACT-influenced internet-based CBT for eating disorders and the relation between knowledge acquisition and outcome: a randomized controlled trial. Behav Ther. 2017;48(5):624-637. [FREE Full text] [CrossRef] [Medline]
  70. Högdahl L, Birgegård A, Norring C, de Man Lapidoth J, Franko MA, Björck C. Internet-based cognitive behavioral therapy for bulimic eating disorders in a clinical setting: results from a randomized trial with one-year follow-up. Internet Interv. 2022;31:100598. [FREE Full text] [CrossRef] [Medline]
  71. Takahasi F, Takegawa S, Okumura Y, Suzuki S. Actual condition survey on the implementation of cognitive behavioral therapy at psychiatric clinics in Japan. 2018. URL: [accessed 2023-08-31]

BN: bulimia nervosa
CBT: cognitive behavioral therapy
CONSORT: Consolidated Standards of Reporting Trials
ICBT: internet-based cognitive behavioral therapy
RCT: randomized controlled trial
TAU: treatment as usual
UMIN: University Hospital Medical Information Network

Edited by A Mavragani; submitted 12.06.23; peer-reviewed by J Linnet; comments to author 12.07.23; revised version received 24.07.23; accepted 24.08.23; published 19.09.23.


©Sayo Hamatani, Kazuki Matsumoto, Gerhard Andersson, Yukiko Tomioka, Shusuke Numata, Rio Kamashita, Atsushi Sekiguchi, Yasuhiro Sato, Shin Fukudo, Natsuki Sasaki, Masayuki Nakamura, Ryoko Otani, Ryoichi Sakuta, Yoshiyuki Hirano, Hirotaka Kosaka, Yoshifumi Mizuno. Originally published in JMIR Research Protocols (, 19.09.2023.

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