Efficacy of digital cognitive behavioral therapy for moderate-to-severe symptoms of generalized anxiety disorder: A randomized controlled trial

Background: Cognitive behavioral therapy (CBT) is an efficacious intervention for generalized anxiety disorder (GAD). Digital CBT may provide a scalable means of delivering CBT at a population level. We investigated the efficacy of a novel digital CBT program in those with GAD for outcomes of anxiety, worry, depressive symptoms, sleep difficulty, wellbeing, and participant-specific quality of life.

Methods: This online, two-arm parallel-group superiority randomized controlled trial compared digital CBT with waitlist control in 256 participants with moderate-to-severe symptoms of GAD. Digital CBT (Daylight), was delivered using participants' own smartphones. Online assessments took place at baseline (Week 0; immediately preceding randomization), mid-intervention (Week 3; from randomization), post-intervention (Week 6; primary endpoint), and follow-up (Week 10).

Results: Overall, 256 participants were randomized and intention-to-treat analysis found Daylight reduced symptoms of anxiety compared with waitlist control at post-intervention, reflecting a large effect size (adjusted difference [95% CI]: 3.22 [2.14, 4.31], d = 1.08). Significant improvements were found for measures of worry; depressive symptoms, sleep difficulty, wellbeing, and participant-specific quality of life.

Conclusion: Digital CBT (Daylight) appears to be safe and efficacious for symptoms of anxiety, worry, and further measures of mental health compared with waitlist control in individuals with GAD.