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Lookup NU author(s): Emeritus Professor Jan Scott
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2026 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license. http://creativecommons.org/licenses/by/4.0/Background: We evaluated the long-term clinical and cost-effectiveness of fully automated digital cognitive behavioural therapy for insomnia (dCBT-I) or online patient education (PE) in the Norwegian general population. Methods: A parallel-group, participant-blinded, superiority randomised controlled trial in self-referred adults with significant insomnia symptoms (Insomnia Severity Index [ISI] ≥12). Participants completed automated screening prior to randomisation and outcomes were assessed over 2 years. The primary outcome (9-week clinical effectiveness) has been published. We now report intention-to-treat analyses from the 6-month and 2-year follow-ups. Incremental cost-effectiveness ratio (ICER), with non-parametric bootstrapping, summarized the between-group societal costs in 2019 Euros, and quality-adjusted life years (QALYs). The trial was preregistered at ClinicalTrials.gov (NCT02558647) and followed a prespecified protocol. Findings: 1720 participants (1167 [67.8%] female; mean age 44.4) were randomised between February 26, 2016, and July 1, 2018 (867 to dCBT-I vs. 853 to PE). The final follow-up included 587/1720 (34.1%) participants (dCBT-I = 315; PE = 272), a median of 28.3 months (IQR 22.6 to 34.0) after baseline. At 2-year follow-up the mean ISI was 10.7 (SD 5.9) in the dCBT-I group and 13.4 (5.9) in the PE group (estimated difference: −1.77 [95% CI: −2.65 to −0.90]; Cohen’s d= −0.43). The dCBT-I group reported −€278 [95% CI: −1413 to 858] lower costs and 0.025 QALYs gained [95% CI: 0.010 to 0.041] compared with PE, yielding a 94% probability of cost-effectiveness at €0 willingness-to-pay (ICER: −€10,973 per QALY gained). No harms or adverse events were reported. Interpretation: Compared with online PE, fully automated, low-threshold dCBT-I demonstrates greater short-term (9 week) and longer-term improvements (≥2 years) in insomnia severity and is likely cost-effective over the 2-year horizon. However, effects attenuated over time and long-term certainty is limited by attrition. Funding: Norwegian Council of Research; Liaison Committee for Education, Research and Innovation in Central Norway.
Author(s): Vethe D, Khan ZA, Vestergaard CL, Halsteinli V, Saksvik SB, Vedaa O, Sivertsen B, Morken G, Langsrud K, Ritterband LM, Robert F Smith O, Scott J, Kallestad H
Publication type: Article
Publication status: Published
Journal: The Lancet Regional Health - Europe
Year: 2026
Volume: 66
Online publication date: 08/05/2026
Acceptance date: 15/04/2026
Date deposited: 19/05/2026
ISSN (electronic): 2666-7762
Publisher: Elsevier Ltd
URL: https://doi.org/10.1016/j.lanepe.2026.101691
DOI: 10.1016/j.lanepe.2026.101691
Data Access Statement: Norwegian regulation does not allow for the sharing of these data after completion of the study. Statistical code is available upon reasonable request from the corresponding author.
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