O027 Engagement and treatment effects across the lifespan: digital CBT-I intervention

Abstract Insomnia Disorder affects 12-14% Australians, and associated with significant mental health concerns. It is especially prevalent in aging populations, and is also a risk factor for negative later-life health outcomes. There are many barriers to the delivery of Cognitive Behavioural Therapy for Insomnia (CBT-I), the gold standard treatment for insomnia. Digital delivery of CBT-I can bypass these access barriers. Given the growing aging population, it is important to understand treatment effectiveness and adherence to digital CBT-I (dCBT-I) programs across the lifespan. Methods Sample included 9567 participants enrolled in the 4 lesson, self-directed THIS WAY UP dCBT-I program (www.thiswayup.org.au) between January 2022 and December 2023. Participants completed the Insomnia Severity Index (ISI) and the Kessler Psychological Distress scale (K-10) before each lesson. Linear mixed models examined age (18-25, 26-39, 40-65, 66-79, 80+) and timepoint (Lesson 1, Lesson 4) effects for ISI and K10. Results Moderate-large effect size reductions in ISI were observed for all age groups (p’s < 0.001; g = 0.56-1.01), which significantly differed by age group; 26–39-year-olds improved faster on ISI compared to all other age groups, except 80+ (F(df) = 24.12 (4); p<.001). Reductions in K-10 were observed for all age groups (p<.001; g = -0.11-0.16), and did not differ between age groups (F(df) = 12.24 (4); p=.02). Older adults (aged 66+) were 2-3 times more likely to complete all lessons compared to 18–39-year-olds (p<.001). Discussion This dCBT-I program was effective at reducing insomnia severity and psychological distress across the lifespan. Older adults in community benefit from dCBT-I comparably to younger ages and should be recommended digital interventions.