Background: Cognitive Behaviour Therapy for Insomnia (CBT-I) delivered through the Internet is effective as a treatment in reducing insomnia in individuals seeking help for insomnia. CBT-I also lowers levels of depression in this group. However, it is not known if targeting insomnia using CBT-I will lower depressive symptoms, and thus reduce the risk of major depressive episode onset, in those specifically at risk for depression. Therefore, this study aims to examine whether Internet delivery of fully automated self-help CBT-I designed to reduce insomnia will prevent depression.
Method/design: A sample of 1,600 community-dwelling adults (aged 18-64), who screen positive for both subclinical levels of depressive symptoms and insomnia, will be recruited via various media and randomised to either a 9-week online insomnia treatment programme, Sleep Healthy Using The internet (SHUTi), or an online attention-matched control group (HealthWatch). The primary outcome variable will be depression symptom levels at the 6-month post-intervention on the Patient Heath Questionnaire-9 (PHQ-9). A secondary outcome will be onset of major depressive episodes assessed at the 6-month post-intervention using 'current' and 'time from intervention' criteria from the Mini International Neuropsychiatric Interview.
Discussion: This trial is the first randomised controlled trial of an Internet-based insomnia intervention as an indicated preventative programme for depression. If effective, online provision of a depression prevention programme will facilitate dissemination.
Trial registration: Australian New Zealand Clinical Trials Registry (ANZCTR), Registration number: ACTRN12611000121965.