Improving adherence to unguided Internet-based therapy for obsessive-compulsive disorder: A randomized controlled trial.

Adherence to internet-based cognitive-behavioral therapy (iCBT) is often low, possibly reducing its potential. The current study set out to test whether adherence and effects of unguided iCBT for obsessive-compulsive disorder (OCD) could be improved by varying the degree of autonomy in which modules are completed (free choice vs. fixed order). We randomized 151 individuals with OCD to either an unguided iCBT with a fixed (iCBTfixed) or a free-choice (iCBTfree+) order of the modules. We assessed participants at baseline (t0), eight weeks (t1), and 16 weeks (t2). Primary outcomes were adherence (utilization time, modules completed) and change in OCD severity (Y-BOCS). Secondary outcomes included depression, self-esteem, and treatment satisfaction. We calculated intent-to-treat (ITT) and complete case (CC) analyses. Analyses showed that both iCBT programs significantly reduced OCD severity. While groups did not differ on the ITT analyses, for the CC analyses, a greater improvement was found in the iCBTfixed in comparison to the iCBTfree+ group regarding OCD severity and quality of life, with medium effect sizes from t0 to t1 (η p 2 = 0.067–0.077). Time of utilization and number of modules completed did not differ between groups. No placebo control group, short follow-up period, self-report assessment. iCBT is effective in improving OCD. Despite similar adherence in the fixed versus the free-choice module order, the study offers tentative evidence that a fixed order of content is associated with better effects. More research on the effects of adherence on outcome is necessary. • Both unguided iCBT programs in the study reduced OCD symptom severity. • Utilization time and modules completed were not related to outcome. • Tentative evidence that a fixed order of content is associated with better effects [ABSTRACT FROM AUTHOR]