To Örebro University

The purpose with the investigation was to examine whether improvements in pre-sleep cognitive arousal, unhelpful beliefs about sleep, and maladaptive sleep behaviors mediate the outcomes in in-person CBT-I. Fifty-eight participants with insomnia were administered either cognitive behavioral therapy or belonged to a waitlist. At pre- and post-treatment, participants completed questionnaires and sleep diaries assessing cognitive arousal, unhelpful beliefs about sleep, maladaptive sleep behaviors, insomnia severity, dysfunction, and subjective sleep parameters. Outcome measures were re-administered at a 3-month follow-up. Decreases in cognitive arousal mediated the effect on dysfunction. Reductions in unhelpful beliefs mediated the treatment effect on insomnia severity and dysfunction. Decreases in bedtime variability mediated the outcome on insomnia severity, and reductions in time in bed had a mediating effect on total wake time. Neither rise time variability nor napping mediated the improvements. A reversed model, in which the outcomes were used as mediators, showed less fit with the current data, indicating that change in the psychological processes as mediators of improvement in the outcomes was the most plausible conclusion. These findings are clearly supportive of cognitive-behavioral models of insomnia by highlighting cognitive arousal, unhelpful beliefs about sleep, and maladaptive sleep behaviors as mediators in the treatment of insomnia. The results are also important for clinical work and for testing new approaches in future research.