Treatment effects in favor of digital cognitive behavioral therapy were observed for insomnia severity, sleep efficiency, cognitive failures, fatigue, sleepiness, depression, and anxiety.
Simon D. Kyle, MA, PhD
Newly published results from the Defining the Impact of Sleep improvement on Cognitive Outcomes (DISCO) trial revealed that digital cognitive behavioral therapy (dCBT) significantly decreases self-reported cognitive impairment at post-treatment in patients with insomnia, with the effects of treatment maintained for 6 months.1
The estimated adjusted mean difference at 10 weeks post-randomization on the British Columbia Cognitive Complaints Inventory (BC-CCI) was –3.03 (95% CI, –3.60 to –2.47; P <.0001; d = –0.86), indicating less cognitive impairment reported among those in the dCBT group compared to the wait-list control group.
Lead author Simon D. Kyle, MA, PhD, associate professor, program director, Oxford Online Programme in Sleep Medicine, University of Oxford, and colleagues aimed to examine the impact of dCBT for insomnia on both self-reported cognitive impairment and objective cognitive performance.
DISCO was an online, 2-arm, single-blind, randomized clinical trial of dCBT that included 410 patients with insomnia who reported difficulties with concentration or memory that were assigned to either dCBT (n = 205) or wait-list control (n = 205).
The large treatment effects previously mentioned were maintained for 24 weeks (estimated adjusted mean difference, –3.41; 95% CI, –4.06 to –2.76; P <.0001: d = –0.96), with the dCBT group (unadjusted mean, 5.51; standard deviation [SD], 3.69) reporting less cognitive impairment than the control group (unadjusted mean, 8.98; SD, 4.23).
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Retention was 82% at 10 weeks and 74% at 24 weeks, and differed by group, with the dCBT group less likely to provide outcome data than control (10 weeks: 76% for dCBT vs 88% for control; 24 weeks: 66% for dCBT vs 81% in control).
Kyle and colleagues noted that both insomnia severity (ISI) at 10 weeks (d = –1.57) and 24 weeks (d = –1.60) had a large treatment effect in the dCBT group, with less insomnia symptoms. Similarly, the same effect size was seen in the dCBT group for sleep deficiency at 10 weeks (d = 0.91) and 24 weeks (d = 0.72), with more patients experiencing higher sleep efficiency scores.
Notably, for objective cognitive performance, there were no significant group differences at 10 or 24 weeks, or on any of the performance tests (d range = –0.09 to 0.11).
Fatigue, which was measured with the Multidimensional Fatigue Inventory (MFI) reported lower levels in the dCBT group at both 10 weeks (d range = –0.34 to –0.70) and 24 weeks (d range = –0.42 to –0.76). Similarly, the dCBT group reported significantly lower levels of sleepiness, measured on Epworth Sleepiness Scale (ESS), at 10 weeks (d = –0.42) and 24 weeks (d = –0.44).
Treatment with dCBT was also associated with less depressive symptoms at both 10 and 24 weeks compared to the control group (d = –0.68 and d = –0.64, respectively).
The 2 groups did not differ in terms of proportion using prescribed sleep medication, defined as at least 1 night in the past 14 days, at 10 weeks (adjusted odds ratio = 0.50; 95% CI, 0.13–1.98) or 24 weeks (adjusted odds ratio = 0.35; 95% CI, 0.07–1.79). Significantly fewer patients in the dCBT arm reported using non-prescription sleep remedies, defined as at least 1 night in the past 14 days, at both 10 (adjusted odds ratio = 0.20; 95% CI, 0.06–0.66) and 24 weeks (adjusted odds ratio = 0.10; 95% CI, 0.03–0.39).
Kyle and colleagues concluded, “the field requires rigorously designed studies, incorporating sensitive measures of performance and sleep physiology in order to further delineate the effects of insomnia treatment on cognitive health.”
The impact of dCBT have been well-documented before. A recently released study from a Markov model analysis suggested that dCBT is the most cost-effective treatment for insomnia, particularly in comparison to group CBT, pharmacotherapy, and individual CBT.
Additional data from the study showed that in comparison to no insomnia treatment, with a net positive monetary benefit of $681.06 every 6 months per individual, confirmed by bootstrap sensitive analysis in 94.7% of simulations. In comparison to the other 3 insomnia treatments, the digital CBT intervention offered the smallest incremental cost-effectiveness ratio, of –$3124.73.2