Sleep-specific outcomes attributable to digitally delivered cognitive behavioral therapy for insomnia in adults with insomnia and depressive symptoms

Objective: Randomized controlled trials (RCTs) of digitally delivered Cognitive Behavioral Therapy for insomnia (CBT-I) have demonstrated reductions in insomnia severity, depression symptoms, anxiety symptoms, and suicidal ideation. The present study aimed to evaluate the effectiveness of self-guided, digital CBT-I to improve sleep-specific outcomes. Method: An RCT of Australian adults with insomnia and depressive symptoms (N = 1149) compared SHUTi, a digital CBT-I intervention, with HealthWatch, an attention-matched control internet program, at baseline, posttest (9 weeks) and at 6-, 12-, and 18-month follow-ups. Online sleep diaries were used to derive measures of sleep-onset latency (SOL), wake after sleep onset (WASO), sleep efficiency (SE), number of awakenings, sleep quality, and total sleep time (TST). Results: Participants in the SHUTi condition had greater improvements at posttest compared with control for: SOL, WASO, SE, number of awakenings, and sleep quality. These improvements were sustained at every follow-up (p <.02 for all outcomes except TST, in which statistically significant increases were observed only at 12- and 18-months). Conclusions: Digitally delivered CBT-I produced lasting improvements in sleep outcomes among adults with insomnia and depressive symptoms. Findings provide further evidence of long-term improvements associated with a digital therapeutic for insomnia, compared to an attention-control condition.