The aim of this study was to compare guided Internet-delivered to group-delivered cognitive behavioral therapy (CBT) for insomnia. We conducted an 8-week randomized controlled non-inferiority trial with 6-months follow-up. Participants were forty-eight adults with insomnia, recruited via media. Interventions were guided Internet-delivered CBT (ICBT) and group-delivered CBT (GCBT) for insomnia. Primary outcome measure was the Insomnia Severity Index (ISI), secondary outcome measures were sleep diary data, depressive symptoms, response- and remission rates. Both treatment groups showed significant improvements and large effect sizes for ISI (Within Cohen's d: ICBT post = 1.8, 6-months follow-up = 2.1; GCBT post = 2.1, 6-months follow-up = 2.2). Confidence interval of the difference between groups post-treatment and at FU6 indicated non-inferiority of ICBT compared to GCBT. At post-treatment, two thirds of patients in both groups were considered responders (ISI-reduction > 7p). Using diagnostic criteria, 63% (ICBT) and 75% (GCBT) were in remission. Sleep diary data showed moderate to large effect sizes. We conclude that both guided Internet-CBT and group-CBT in this study were efficacious with regard to insomnia severity, sleep parameters and depressive symptoms. The results are in line with previous research, and strengthen the evidence for guided Internet-CBT for insomnia.
Trial registration: The study protocol was approved by, and registered with, the regional ethics review board in Linköping, Sweden, registration number 2010/385-31.
Keywords: CBT; Group therapy; Insomnia; Internet; Non-inferiority; Psychotherapy.
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