Effectiveness of a guided digital self-help intervention to improve sleep and the biological clock in university students - Study protocol for a randomized controlled trial

Background: Sleep problems occur in many university students which affects their mental health and daily functioning. Cognitive behavioural therapy for insomnia (CBT-I) has been proven effective in adults but research in university students, who struggle to maintain a 24-hour rhythm, is still limited. We hypothesize that a guided digital CBT-I intervention, enriched with components on the biological clock ( 'i-Sleep & BioClock') ) will be effective in reducing insomnia severity and improving mental health outcomes for students with sleep problems. Objectives: We aim to evaluate the effectiveness of a guided online sleep and biological clock self-help intervention in improving sleep, depression symptoms, anxiety symptoms, functioning, academic performance, and quality of life in university students at 6 weeks and 18 weeks. Methods: This is a two-arm parallel-group superiority randomized controlled trial, comparing a 5-week guided online 'i-Sleep & BioClock' intervention to online psychoeducation (PE). We aim to include 192 university students (Bachelor, Master, and PhD) with at least subthreshold insomnia (Insomnia Severity Index >= 10), aged >= 16, who can speak Dutch or English. We are excluding students with current risk for suicide or night shifts. The primary outcome is insomnia severity. Secondary outcomes include sleep estimates (sleep and light exposure diary), depression, anxiety, functioning, quality of life, and academic performance. The effectiveness of the intervention compared to online PE will be evaluated using linear mixed models. Discussion: The current study tests the effectiveness of an online self-help intervention for university students who suffer from sleep problems. This trial builds upon an open feasibility study and will provide evidence of an online guided self-help program for students. The findings of this study will determine the potential wider dissemination of the intervention to address the high need for available and accessible help for students experiencing insomnia. Trial registration: ClinicalTrials.Gov (NCT06023693), registered on August 3rd, 2023.