A single-arm pilot study of guided self-help treatment based cognitive behavioral therapy for bulimia nervosa in Japanese clinical settings

R. Setsu, K. Asano, N. Numata, M. Tanaka, H. Ibuki, T. Yamamoto, R. Uragami, J. Matsumoto, Y. Hirano, M. Iyo, E. Shimizu, M. Nakazato

Guided self-help treatments based on cognitive behavioral therapy (CBT-GSH) are regarded as a first-line effective treatment for bulimia nervosa (BN). With limited application for CBT-GSH in Japanese clinical settings, we conducted a single arm pilot study in order to confirm the acceptability and availability of CBT-GSH in Japan. 25 women with BN received 16-20 sessions of face-to-face CBT-GSH. Primary outcomes were the completion rate of intervention and abstinence rates from objective bingeing and purging as assessed by the Eating Disorder Examination. Secondary outcomes were other self-report measurements of the frequency of bingeing and purging, and characteristic psychopathologies of eating disorders. Assessments were conducted before CBT as baseline as well as after CBT. 92% (23/25) of the participants completed the CBT sessions. After CBT-GSH, 40% (10/25) of the participants (intention-to-treat) achieved symptom abstinence. The mean binge and purge episodes during the previous 28 days improved from 21.88 to 10.96 (50% reduction) and from 22.44 to 10.88 (52% reduction), each (before CBT-GSH to after CBT-GSH), and the within-group effect sizes were medium (Cohen's d = 0.67, 0.65, each). Our study provided a preliminary evidence about the feasibility of CBT-GSH in Japanese clinical settings for the future. Trial registration This study was registered retrospectively in the national UMIN Clinical Trials Registry on July 10, 2013 (registration ID: UMIN000011120).