Culturally adapted digital cognitive behavioral therapy for insomnia in South Korea – a double-blind randomized controlled trial

Culturally adapted digital cognitive behavioral therapy for insomnia (dCBT-I) has the potential to enhance engagement and treatment outcomes, yet its efficacy compared to patient education (PE) remains understudied. This multicenter, double-blind, randomized controlled trial evaluated dCBT-I versus a PE application in individuals with chronic insomnia in South Korea. The primary outcome was Insomnia Severity Index (ISI) scores. Secondary and exploratory outcomes included sleep diary measures, self-reported scales assessing sleep quality, maladaptive sleep-related beliefs, daytime sleepiness, anxiety, and depressive symptoms. Of 52 participants (mean [SD] age, 38.6 [12.4] years; 64% female), 27 were randomized to digital cognitive behavioral therapy for insomnia (dCBT-I) and 25 to patient education (PE). Post-intervention data were available for 50 participants (dCBT-I: n = 25; PE: n = 25). Further exploratory 3-month follow-up data were available for 25 participants in the dCBT-I group. Both groups showed significant within-group improvements in ISI scores, with no significant between-group differences. The dCBT-I group demonstrated greater improvements in sleep quality (PSQI: Cohen d = 1.02, P = .012) and maladaptive sleep-related beliefs (DBAS-16: Cohen d = 1.24, P = .003). Sleep diary data indicated significant reductions in sleep onset latency (Cohen d = -0.15, P = .005) and increases in sleep efficiency (Cohen d = 0.16, P = .003) in the dCBT-I group. Adherence to dCBT-I was high (89% completed all modules), and satisfaction ratings were higher than in the PE group. While both interventions improved insomnia severity, dCBT-I provided additional benefits in sleep-related outcomes, supporting the feasibility and potential clinical utility of this culturally adapted intervention. Clinical Trial Registration: https://clinicaltrials.gov/study/NCT05822999, ClinicalTrials.gov (NCT05822999).