Dysfunctional beliefs and attitudes about sleep (DBAS) mediate outcomes in dCBT-I on psychological distress, fatigue, and insomnia severity.

Digital cognitive behavioral therapy for insomnia (dCBT-I) improves several sleep and health outcomes in individuals with insomnia. This study investigates whether changes in Dysfunctional Beliefs and Attitudes about Sleep (DBAS) during dCBT-I mediate changes in psychological distress, fatigue, and insomnia severity. The study presents a secondary planned analysis of data from 1073 participants in a randomized control trial (Total sample = 1721) of dCBT-I compared with patient education (PE). Self-ratings with the Dysfunctional Beliefs and Attitudes about Sleep (DBAS), the Hospital Anxiety Depression Scale (HADS), the Chalder Fatigue Scale (CFQ), and the Insomnia Severity Index (ISI) were obtained at baseline and 9-week follow-up. Hayes PROCESS mediation analyses were conducted to test for mediation. sDBAS scores were significantly reduced at 9-week follow-up for those randomized to dCBT-I (n = 566) compared with PE (n = 507). The estimated mean difference was -1.49 (95% CI -1.66 to -1.31, p < .001, Cohen's d. = 0.93). DBAS mediated all the effect of dCBT-I on the HADS and the CFQ, and 64% of the change on the ISI (Estimated indirect effect -3.14, 95% CI -3.60 to -2.68) at 9-week follow-up compared with PE. Changes in the DBAS fully mediated the effects of dCBT-I on psychological distress and fatigue, and the DBAS partially mediated the effects on insomnia severity. These findings may have implications for understanding how dCBT-I works and highlights the role of changing cognitions in dCBT-I.

Faaland P ，Vedaa Ø ，Langsrud K ，Sivertsen B ，Lydersen S ，Saksvik SB ，Vestergaard CL ，Kjørstad K ，Vethe D ，Ritterband LM ，Harvey AG ，Stiles TC ，Scott J ，Kallestad H ... -  《-》

Digital cognitive behavioral therapy for insomnia for people with comorbid psychological distress: A large scale randomized controlled trial.

To examine if comorbid anxiety and depression symptoms (psychological distress) moderate intervention effect in participants receiving digital Cognitive Behavioral Therapy for Insomnia (dCBT-I) in a large-scale randomized controlled trial (RCT), compared to a patient education (PE) control condition. Further, we investigate if dCBT-I reduced levels of psychological distress for those with insomnia and comorbid psychological distress. 1721 participants with insomnia completed online assessments of sleep, fatigue and psychological distress, at baseline and at nine-week follow-up. Primary outcome was Insomnia Severity Index (ISI), and secondary outcomes included self-reported sleep (diary), cognition, fatigue, and psychological distress. Participants with psychological distress (HADS>16) were separated from participants without psychological distress. Linear mixed models in SPSS were conducted to test the effects of the intervention. At nine-week follow-up we found no difference in effect of the intervention between those who had comorbid psychological distress vs. those without psychological distress in terms of insomnia severity (p = 0.552) and fatigue (p = 0.744). Both groups had large effect size improvements on insomnia severity (p < 0.001=), small to medium (Cohen d < 0.08) improvements on fatigue (p < 0.01=) and sleep efficiency (p < 0.001), and small improvement on other sleep diary measures, compared to their respective control group. The psychological distress group showed a small, but statistically significant decrease in psychological distress (d = 0.2, p < 0.05) with dCBT-I compared to PE. dCBT-I is a viable treatment for Insomnia also for those who have comorbid psychological distress.

Skoglund H ，Sivertsen B ，Kallestad H ，Vedaa Ø ... -  《-》

The effect of sleep-wake intraindividual variability in digital cognitive behavioral therapy for insomnia: a mediation analysis of a large-scale RCT.

Digital cognitive behavioral therapy for insomnia (dCBT-I) is an effective treatment for insomnia. However, less is known about mediators of its benefits. The aim of the present study was to test if intraindividual variability in sleep (IIV) was reduced with dCBT-I, and whether any identified reduction was a mediator of dCBT-I on insomnia severity and psychological distress. In a two-arm randomized controlled trial (RCT), 1720 adults with insomnia (dCBT-I = 867; patient education about sleep = 853) completed the Insomnia Severity Index (ISI), the Hospital Anxiety and Depression Scale (HADS) and sleep diaries, at baseline and 9-week follow-up. Changes in IIV were analyzed using linear mixed modeling followed by mediation analyses of ISI, HADS, and IIV in singular sleep metrics and composite measures (behavioral indices (BI-Z) and sleep disturbance indices (SI-Z)). dCBT-I was associated with reduced IIV across all singular sleep metrics, with the largest between-group effect sizes observed for sleep onset latency (SOL). Reduced IIV for SOL and wake after sleep onset had the overall greatest singular mediating effect. For composite measures, SI-Z mediated change in ISI (b = -0.74; 95% confidence interval (CI) -1.04 to -0.52; 13.3%) and HADS (b = -0.40; 95% CI -0.73 to -0.18; 29.2%), while BI-Z mediated minor changes. Reductions in IIV in key sleep metrics mediate significant changes in insomnia severity and especially psychological distress when using dCBT-I. These findings offer important evidence regarding the therapeutic action of dCBT-I and may guide the future development of this intervention. Name: Overcoming Insomnia: Impact on Sleep, Health and Work of Online CBT-I Registration number: NCT02558647 URL: https://clinicaltrials.gov/ct2/show/NCT02558647?cond=NCT02558647&draw=2&rank=1.

Vestergaard CL ，Vedaa Ø ，Simpson MR ，Faaland P ，Vethe D ，Kjørstad K ，Langsrud K ，Ritterband LM ，Sivertsen B ，Stiles TC ，Scott J ，Kallestad H ... -  《-》

Effects of digital cognitive behavioural therapy for insomnia on insomnia severity: a large-scale randomised controlled trial.

Although several large-scale randomised controlled trials have shown the efficacy of digital cognitive behavioural therapy for insomnia (dCBT-I), there is a need to validate widespread dissemination of dCBT-I using recommended key outcomes for insomnia. We investigated the effect of a fully automated dCBT-I programme on insomnia severity, sleep-wake patterns, sleep medication use, and daytime impairment. We did a parallel-group superiority randomised controlled trial comparing dCBT-I with online patient education about sleep. The interventions were available through a free-to-access website, publicised throughout Norway, which incorporated automated screening, informed consent, and randomisation procedures, as well as outcome assessments. Adults (age ≥18 years) who had regular internet access and scored 12 or higher on the Insomnia Severity Index (ISI) were eligible for inclusion, and were allocated (1:1) to receive dCBT-I (consisting of six core interactive sessions to be completed over 9 weeks) or patient education (control group). Participants were masked to group assignment and had no contact with researchers during the intervention period. The primary outcome was the change in ISI score from baseline to 9-week follow-up, assessed in the intention-to-treat population. This trial is registered with ClinicalTrials.gov (NCT02558647) and is ongoing, with 2-year follow-up assessments planned. Between Feb 26, 2016, and July 1, 2018, 5349 individuals commenced the online screening process, of which 1497 were ineligible or declined to participate, 2131 discontinued the screening process, and 1721 were randomly allocated (868 to receive dCBT-I and 853 to receive patient education). At 9-week follow-up, 584 (67%) participants in the dCBT-I group and 534 (63%) in the patient education group completed the ISI assessment. The latent growth model showed that participants in the dCBT-I group had a significantly greater reduction in ISI scores from baseline (mean score 19·2 [SD 3·9]) to 9-week follow-up (10·4 [6·2]) than those in the patient education group (from 19·6 [4·0] to 15·2 [5·3]; estimated mean difference -4·7 (95% CI -5·4 to -4·1; Cohen's d -1·21; p<0·001). Compared with patient education, the number needed to treat with dCBT-I was 2·7 (95% CI 2·4 to 3·2) for treatment response (ISI score reduction ≥8) and 3·2 (2·8 to 3·8) for insomnia remission (ISI score <8). No adverse events were reported to the trial team. dCBT-I is effective in reducing the severity of symptoms associated with the insomnia disorder. These findings support the widespread dissemination of dCBT-I. Future research is needed to identify the moderators of response and to improve targeting. Norwegian Research Council; Liaison Committee for Education, Research and Innovation in Central Norway.

Vedaa Ø ，Kallestad H ，Scott J ，Smith ORF ，Pallesen S ，Morken G ，Langsrud K ，Gehrman P ，Thorndike FP ，Ritterband LM ，Harvey AG ，Stiles T ，Sivertsen B ... -  《The Lancet Digital Health》

Effect of Digital Cognitive Behavioral Therapy for Insomnia on Health, Psychological Well-being, and Sleep-Related Quality of Life: A Randomized Clinical Trial.

Espie CA ，Emsley R ，Kyle SD ，Gordon C ，Drake CL ，Siriwardena AN ，Cape J ，Ong JC ，Sheaves B ，Foster R ，Freeman D ，Costa-Font J ，Marsden A ，Luik AI ... -  《-》