Internet-delivered cognitive-behavioral therapy for insomnia and comorbid symptoms.

Background: Cognitive-behavioral therapy for insomnia (CBTi) is considered the standard treatment. The internet has proven to be a useful and successful tool of providing CBTi. However, few studies have investigated the possible effect of unguided internet-delivered CBTi (ICBTi) on comorbid psychological symptoms and fatigue.

Methods: Based on a randomized controlled trial, we investigated whether unguided ICBTi had an effect on comorbid psychological symptoms. Adults with insomnia ( = 181; 67% women; mean age 44.9 years [SD 13.0]) were randomized to ICBTi ( = 95) or to an online patient education condition ( = 86) for a nine-week period.

Results: The results from mixed linear modelling yielded medium to large between-group effect sizes from pre- to post-treatment for symptoms of anxiety or depression ( = -0.57; 95% CI = 0.79-0.35) and fatigue ( = 0.92; 95% CI = 1.22-0.62). The ICBTi group was reassessed at a 6-month non-randomized follow-up, and the completing participants had on the average a significant increase (from the post-assessment) on symptoms of anxiety or depression, while the reduction in symptoms of fatigue (on post-assessment) was maintained. However, due to high dropout attrition and no control group data, caution should be made regarding the long-term effects. In conclusion, the present findings show that unguided ICBTi positively influence comorbid symptoms in the short-term, thereby emphasizing the clinical relevance of unguided ICBTi.

Trial Registration: ClinicalTrials.gov identifier: NCT02261272.