Smartphone-delivered cognitive behavioral therapy for insomnia: A preliminary randomized controlled trial

Cognitive behavioral therapy for insomnia (CBT-I) is the first-line treatment for insomnia, but many individuals lack access. This study evaluated the preliminary efficacy of Hvil®, a 9-week, fully automated, smartphone delivered eCBT-I program, in reducing insomnia severity.

Adults with insomnia (Insomnia Severity Index ≥10) were randomly assigned to an eCBT-I intervention via Hvil® or to a waitlist control group. The primary outcome of insomnia severity was assessed at baseline, weekly during the intervention, and post-intervention. Secondary outcomes included fatigue at baseline and post-intervention and sleep diary-based outcomes assessed daily during the study period. Mixed linear models (MLMs) based on the intent-to-treat sample were used to assess group differences over time. Moderating effects of demographic characteristics and adherence were explored.

A total of 165 participants were randomized to the intervention (n = 83) or control group (n = 82). A significant group × time interaction was observed for insomnia severity (p < .001) favoring the intervention group, yielding a clinically meaningful effect size (Cohen's d = 0.66). Significant improvements were also noted in fatigue, sleep quality, time in bed, and nocturnal awakenings. Effect sizes for secondary outcomes ranged from 0.15 (total sleep time) to 1.06 (time in bed). Greater engagement with the Hvil® app was associated with larger reductions in insomnia severity (p < .001).

Hvil®, an automated eCBT-I intervention, demonstrated significant efficacy in reducing insomnia severity among adults in the general population. While attrition was substantial, the results suggest its potential as a scalable, accessible intervention.