Unguided iCBT-I can be successfully disseminated to the public in a naturalistic setting.

Adherence to the iCBT-I program was markedly higher than other unguided iCBT programs when accessed in naturalistic settings.

65% of participants who reported pre-treatment insomnia severity at clinical levels remitted following treatment with unguided iCBT-I.

Abstract

Background Insomnia is the most prevalent sleep disorder worldwide, and regularly co-occurs with anxiety and depression. Cognitive behavioural therapy is the gold standard treatment for insomnia (CBT-I), however demand for treatment providers drastically exceeds supply. Internet-delivered programs for insomnia (iCBT-I) improve treatment access. However the effects of unguided iCBT-I for individuals with comorbidities within a naturalistic setting remains unexplored. We developed a novel unguided iCBT-I program and evaluated its impact on insomnia, psychological distress, and wellbeing when accessed by the public.

Methods 317 participants experiencing insomnia for over 3 months enrolled in the program. The program consisted of 4 lessons delivered online with automated web support. Insomnia symptoms, psychological distress, and general wellbeing were assessed at lesson 1 and 4. Intention-to-treat linear mixed models were used to examine effects on insomnia, distress, and wellbeing.

Results Participants experienced large (g = 1.11) and significant reductions in insomnia, moderate (g = 0.55) and significant reductions in distress, and small (g = 0.37) but significant improvements in wellbeing. 65% of participants who reported pre-treatment insomnia severity at clinical levels remitted following treatment.

Limitations To examine the program in a naturalistic setting, we did not employ a control group or follow participants beyond the completion of treatment.