Objective Internet-based cognitive behavioral self-help treatments (iCBT) have been shown to successfully reduce the distress associated with tinnitus. Despite this success, little is known about the mechanisms that make iCBT for tinnitus sufferers work. Availability of minimal therapeutic support is assumed to positively influence treatment outcome in iCBT, but the lower limit of required support is not known. In face-to-face therapy, patients' positive outcome expectations have demonstrated an advantageous effect on outcome. The first aim of our study was thus to investigate the role of ‘on demand’ therapeutic guidance vs. no therapeutic support on treatment outcome in an iCBT for tinnitus sufferers. Our second aim was to investigate whether positive outcome expectations can predict treatment outcome. Methods A total of 112 tinnitus patients were randomly assigned to one of two groups (support-on-demand or non-support). Both groups received an established iCBT treatment for tinnitus. While participants in the support group (n=56) could ask a therapist for additional support, those in the other (n=56) received no therapeutic guidance. Tinnitus distress was assessed pre- and post-treatment via the Tinnitus Handicap Inventory (THI) and the Mini-Tinnitus Questionnaire (Mini-TQ). Pre-treatment outcome expectations were assessed using the Patient Questionnaire on Therapy Expectation and Evaluation (PATHEV). Results We observed significantly less tinnitus distress in the THI (support: t(55)=7.51, p≤.001; non-support: t(55)=7.68, p≤.001) and Mini-TQ (support: t(55)=8.24, p≤.001; non-support: t(55)=8.46, p≤.001) in both groups from pre- to post-treatment, but no significant differences between the groups or interactions. The PATHEV subscale “Hope of Improvement” significantly predicted treatment outcome as measured by the THI (β=0.28, p=.027). Conclusions The iCBT self-help program is a good treatment option for tinnitus sufferers whether or not support-on-demand is provided. Furthermore, our results show the importance of outcome expectations to the efficacy of iCBT in tinnitus patients. Future research should focus on discovering further predictors of treatment outcome. 
The role of “on demand” therapist guidance vs. no support in the treatment of tinnitus via the internet: A randomized controlled trial