Digital App Based Cognitive Behaviour Therapy CBT-I Course Improving Insomnia and Sleep Hygiene: A Randomised Controlled Trial.

Problems with initiating and maintaining sleep are among the most common health complaints, with prevalence rates exceeding 50% depending on the survey. Preventing the progression to chronic insomnia may reduce public healthcare costs and prevent secondary illnesses. This study examined the effectiveness of a novel app-based digital course using cognitive behavioural therapy for insomnia (CBT-I) in preventing the manifestation of insomnia among individuals with sub-threshold to moderate symptoms. Participants were assigned to an intervention group (N = 191, ages 20-75) or a waitlist control group (N = 72, ages 22-77) and assessed at three time points: Pre-intervention (T0), Post-intervention (T1, after 7-week course) and Follow-up (T2, 3 months after course initiation) using the Insomnia Severity Index (ISI), Sleep Hygiene Index (SHI) and sleep diary entries. Results showed a significant reduction in insomnia severity (-4.8 ± 3.7 ISI points) and improved sleep hygiene (-3.5 ± 4.5 SHI points) from T0 to T1 (d = 1.35, and d = 0.69, respectively), with stable effects maintained at the 3-month follow-up. Remission was achieved by 48% of the intervention group compared to 18% of the control group. Improvements were also observed in sleep latency, sleep efficiency and reductions in nocturnal awakenings and wake time after sleep onset (d = 0.25-0.71). Activating evening activates, napping, irregular bedtimes, uncomfortable sleep environment, perceived stress and rumination significantly reduced (d = 0.16-0.59). Notably, 68% of users reported sustained improvements in their sleep. The findings indicate that various sleep hygiene behaviours can be effectively modified through an app-based CBT-I intervention. Trial Registration: This study was pre-registered at Open Science Framework https://osf.io/yj2va.