Expected increase in health competence improves over modules of an unguided internet-based cognitive-behavioural therapy for obsessive-compulsive disorder.

Internet-based cognitive-behavioural interventions (iCBT) are a valuable alternative to face-to-face psychotherapy. An unguided iCBT program has shown to be efficacious for patients with obsessive-compulsive disorder (OCD). However, the modules' mode of action is not well understood, which is the objective of the present study. Twenty-five patients with OCD who participated at the iCBT program for 8 weeks answered a questionnaire on their self-efficacy, motivation, expected increase in health competence and experiential avoidance before and after each module and were included in the present analyses. Linear mixed-effects models demonstrated that patients' expected increase in health competence improved over the course of the treatment. No within-module-specific effect was found. The iCBT program was able to improve patients' expected health competence. However, all other variables did not change. The iCBT program should be revised by focusing more strongly on the integration of the content to reduce experiential avoidance and to improve motivation.