Evidence-Based Reviews

Cognitive-behavioral therapy for insomnia: A review of 8 studies

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  • dCBT-I can improve depression and insomnia and has a sustained antidepressant effect.
  • dCBT-I is effective for preventing depression. In other words, the risk of developing depression is decreased when dCBT-I is used to treat insomnia in individuals with minimal to no depression at baseline.

2. Vedaa Ø, Hagatun S, Kallestad H, et al. Long-term effects of an unguided online cognitive behavioral therapy for chronic insomnia. J Clin Sleep Med. 2019;15(1):101-110.

dCBT-I is effective for treating insomnia in the short term; however, little is known about the long-term effectiveness of dCBT-I on sleep and daytime symptoms. Vedaa et al10 evaluated the efficacy of dCBT-I at 18 months after the intervention.

Study design

  • In this randomized controlled trial (RCT), the efficacy of unguided, internet-delivered CBT-I (n = 95) was compared with web-based patient education (n = 86) for patients with chronic insomnia.
  • Participants were assessed at baseline, after a 9-week intervention period, and at 6-month follow-up. Participants in the internet CBT-I group were reassessed at 18 months after the intervention using online questionnaires, including the Insomnia Severity Index (ISI), Bergen Insomnia Scale (BIS), Brief Dysfunctional Beliefs and Attitudes Scale, Hospital Anxiety and Depression Scale, Chalder Fatigue Questionnaire, and sleep diaries.


  • At 18 months, significant improvements were noted from baseline ISI and BIS scores and in levels of daytime fatigue, as well as psychological distress and beliefs about sleep.
  • Sleep diary variables—including sleep onset latency, time awake during the night (wake time after sleep onset), early morning awakening, total sleep time, and sleep efficiency—showed significant improvement from baseline to 18-month follow-up (at least moderate effect size).
  • Improvements were maintained from the completion of the 9-week intervention to follow-up at 18 months.

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