Efficacy of internet-delivered cognitive-behavioral therapy for insomnia – A systematic review and meta-analysis of randomized controlled trials

Summary

Cognitive-behavioral therapy for insomnia (CBT-I) has been shown efficacious, but the challenge remains to make it available and accessible in order to meet population needs. Delivering CBT-I over the internet (eCBT-I) may be one method to overcome this challenge. The objective of this meta-analysis was to evaluate the efficacy of eCBT-I and the moderating influence of various study characteristics. Two researchers independently searched key electronic databases (1991 to June 2015), selected eligible publications, extracted data, and evaluated methodological quality. Eleven randomized controlled trials examining a total of 1460 participants were included. Results showed that eCBT-I improved insomnia severity, sleep efficiency, subjective sleep quality, wake after sleep onset, sleep onset latency, total sleep time, and number of nocturnal awakenings at post-treatment, with effect sizes (Hedges's g) ranging from 0.21 to 1.09. The effects were comparable to those found for face-to-face CBT-I, and were generally maintained at 4–48 wk follow-up. Moderator analyses showed that longer treatment duration and higher degree of personal clinical support were associated with larger effect sizes, and that larger study dropout in the intervention group was associated with smaller effect sizes. In conclusion, internet-delivered CBT-I appears efficacious and can be considered a viable option in the treatment of insomnia.

Introduction

Insomnia is a common clinical condition with an annual prevalence of 10–20% [1] and approximately half (6%) with a chronic trajectory, i.e., persisting for more than 3 mo [2]. Chronic insomnia has been associated with a number of negative health outcomes, including obesity and metabolic dysregulation [3], [4], hypertension and increased risk of myocardial infarction [5], [6], increased susceptibility to infections [7], and depression [8]. While pharmacotherapy remains the most commonly used treatment option, hypnotics such as benzodiazepine receptor agonists are associated with side-effects, dependence, and tolerance over time. They are usually not curative, leading to long-term treatment over many years despite lack of safety and efficacy data beyond 1–2 y [9], [10]. In contrast, cognitive-behavioral therapy for insomnia (CBT-I) has, in several meta-analyses, been found efficacious in improving sleep outcomes [11], [12], ∗[13] with acute effects comparable or superior to those found for pharmacotherapy [14], and these effects have been maintained for up to 3 y [10]. While CBT-I has been shown efficacious and desired by many patients preferring non-pharmacological approaches [15], [16], the challenge remains to make it available and accessible to meet population needs [17] due to the limited availability of trained therapists and the relatively high costs of CBT-I delivered face-to-face [18], [19].

One method to overcome these challenges may be to provide CBT-I over the internet [20]. The first randomized controlled trial (RCT) evaluating internet-delivered CBT-I, published in 2004, compared a 5-wk internet-delivered sleep management program to a waiting list control in a sample with clinical insomnia [21]. The program, which was derived from existing CBT-I manuals [22], ∗[23], included sleep restriction [24], stimulus-control [25], sleep hygiene education [26], cognitive therapy [27], and relaxation techniques [28]. The results showed improvements in several sleep outcomes, including total sleep time (TST), wake after sleep onset (WASO), and sleep efficiency (SE). A meta-analysis published in 2012 [29] provided a quantitative review of four studies and reported statistically significant effects for subjective sleep quality (SQ), SE, sleep onset latency (SOL), number of nocturnal awakenings (NA), and insomnia severity (Cohen's d range: 0.41 to 0.86). While internet-delivered CBT-I appeared to be a promising approach to treating insomnia, the results were considered preliminary given the limited number of studies available at the time of the publication of the review. In addition, no data were provided on publication bias [30] or the robustness of results, i.e., the number of null-findings needed to bring the results to statistical non-significance [31], and only one study examined the effect at a follow-up [32].

Given the rapid development in the field of internet-delivered interventions, we conducted a new systematic review and meta-analysis with the aim of not only evaluating the efficacy of internet-delivered CBT-I, but also to assess long-term effects, robustness of results, and possible publication bias, and to explore the potential moderating effects of relevant study characteristics, including attrition, intervention duration, and the degree of personal clinical support provided during the intervention.