Cognitive processes mediate the effects of insomnia treatment: evidence from a randomized wait-list controlled trial

Introduction: Both guided online and individual face-to-face cognitive behavioral therapy for insomnia (CBT-I) are effective in improving insomnia symptoms and sleep efficiency. Little is known about the underlying mechanisms generating this effect. The present study tests the assumption that pre-sleep arousal, sleep-related worry and dysfunctional beliefs about sleep are mediators in the effect of cognitive behavioral treatment for insomnia. Methods: A secondary analysis was performed on data previously collected from a randomized controlled trial (N = 90). In this trial, participants were randomized to either a face-to-face CBT-I condition, an internet-delivered CBT-I condition, or a wait-list group. This article reports on the efficacy of these interventions on pre-sleep arousal, sleep-related worry, and dysfunctional beliefs. Furthermore, we investigated whether these measures mediated the treatment effect on insomnia severity and sleep efficiency. Results: Both treatment modalities were efficacious for these cognitive measures; however, face-to-face treatment showed superiority over the online treatment. All three cognitive measures mediated the effect on insomnia severity. Sleep-related worry and pre-sleep arousal mediated the effect on sleep efficiency, but dysfunctional beliefs did not. Conclusion: Overall, these results point toward the importance of cognitive processes in the treatment of insomnia, implying that psychological treatments for insomnia may best be guided by (also) targeting these cognitive processes. (c) 2018 Elsevier B.V. All rights reserved.