Diverging paths: Modeling the relation between adverse effects, attitudes, perceived adherence, and treatment effect in an internet-based cognitive-behavioral intervention for obsessive-compulsive disorder.

Background And Aim: The efficacy of internet-based interventions (IBI) for various psychiatric disorders is widely established, but little is known about the mechanisms or possible influencing factors. One of the most prominent problems in IBI is low adherence, but the relationship between adherence and level of improvement is still unclear. Patients' attitudes and beliefs about IBI as well as the experience of adverse effects-another widely neglected topic-may also influence the effectiveness of these interventions. This secondary analysis is aimed at investigating the relationship between adverse effects, attitudes, perceived adherence (i.e., patient's impression of their compliance), and treatment effect in an IBI for obsessive-compulsive disorder (OCD).

Methods: Participants were 151 individuals with symptoms of OCD, of which 59.96% (n = 90) took part in the post-assessment. Attitudes toward IBI were assessed before they used an IBI for OCD; subjective adherence perception and experience of negative effects were assessed afterward. OCD symptom severity was evaluated at two time points, the difference score defining the treatment effect. A path analysis was conducted to test the hypothesized model. Objective and subjective adherence measures were correlated exploratively.

Results: The path analysis revealed that attitude toward IBI and adverse effects were negatively associated with adherence perception but adherence perception was not associated with the treatment effect. Objective and subjective adherence measures did not correlate.

Conclusion: The results did not support the hypothesized model. Since both attitudes toward IBI and adverse effects were negatively associated with adherence perception, managing users' expectations clearly before using IBI might improve adherence. The role of adherence perception on the treatment effect is yet to be clarified.