The objective of the present study was to assess the effect of combining CBT-I with wearing blue-light blocking glasses 90 min prior to bedtime on subjective and objective sleep parameters and daily symptoms (anxiety, depression, hyperarousal). Thirty patients (mean age 48.1 ± 16.13 years, range 21-71, 15 men/15 women) completed a CBT-I group therapy program, with groups randomly assigned to either "active" (blue-light filtering glasses) condition or "placebo" (glasses without filtering properties) condition. Patients were continually monitored by wristwatch actigraphy, kept their sleep diaries and completed a standard questionnaire battery at admission and after the end of the program. Statistical analyses showed a greater reduction of BAI score in "active" (4.33 ± 4.58) versus "placebo" (-0.92 ± 3.68) groups of patients [F = 6.389, p = .019, Cohen's d = 1.26] and significant prolongation of subjective total sleep time in "active" (-36.88 ± 48.68 min.) versus "placebo" (7.04 ± 47.50 min.) [F = 8.56, p < .01, d = 0.91] group. When pre- and post-treatment results were compared in both groups separately, using paired-samples t-tests, significant differences were observed also in the active group for BDI-II score (t = 3.66, p = .003, Cohen's d = 0.95) and HAS score (t = 2.90, p = .012, Cohen's d = 0.75). No significant differences were found in the placebo group. In active group, there was also a significant reduction of subjective sleep latency (t = 2.65, p = .021, d = 0.73) and an increase of subjective total sleep time (t = -2.73, p = .018, d = -0.76) without change in objective sleep duration which was significantly shortened in the placebo group. We provide further evidence that blocking short-wavelength light in the evening hours may be beneficial for patients suffering from insomnia.
Keywords: CBT-I; anxiety; blue-light blocking; chronotherapy; depression; insomnia; sleep.
Effect of blue-blocking glasses in major depressive disorder with sleep onset insomnia: A randomized, double-blind, placebo-controlled study.Chronobiol Int. 2017;34(6):753-761. doi: 10.1080/07420528.2017.1318893. Epub 2017 May 10. Chronobiol Int. 2017. PMID: 28488943 Clinical Trial.
Blocking nocturnal blue light for insomnia: A randomized controlled trial.J Psychiatr Res. 2018 Jan;96:196-202. doi: 10.1016/j.jpsychires.2017.10.015. Epub 2017 Oct 21. J Psychiatr Res. 2018. PMID: 29101797 Free PMC article. Clinical Trial.
Restricting short-wavelength light in the evening to improve sleep in recreational athletes - A pilot study.Eur J Sport Sci. 2019 Jul;19(6):728-735. doi: 10.1080/17461391.2018.1544278. Epub 2018 Nov 14. Eur J Sport Sci. 2019. PMID: 30427265 Clinical Trial.
Novel Augmentation Strategies in Major Depression.Dan Med J. 2017 Apr;64(4):B5338. Dan Med J. 2017. PMID: 28385173 Review.
Cognitive behavioral therapy in persons with comorbid insomnia: A meta-analysis.Sleep Med Rev. 2015 Oct;23:54-67. doi: 10.1016/j.smrv.2014.11.007. Epub 2014 Nov 29. Sleep Med Rev. 2015. PMID: 25645130 Review.