The effect of light therapy on insomnia: A systematic review and meta-analysis

Purpose: Light is a crucial factor influencing sleep arousal patterns. This meta-analysis investigates the efficacy of light therapy (LT) for insomnia treatment.

Methods: Five electronic databases were independently searched by two reviewers until August 2024. The literature screening focused specifically on populations with insomnia complaints treated by LT. Weighted Mean Difference (WMD) and 95% Confidence Interval (CI) were used as statistical tools, while the Cochrane Risk of Bias tool version 2 (RoB 2) was employed to assess the quality of evidence. A total of 10 randomized controlled trials (RCTs) were analyzed.

Results: The results demonstrated that LT showed statistically significant improvements in subjective sleep quality, as evidenced by a reduction in Pittsburgh sleep quality scale (PSQI) scores by -2.89 (95% CI = -4.80 to -0.97) and Insomnia severity index (ISI) scores by -2.16 (95% CI = -4.23 to -0.08) post-intervention. Additionally, actigraphy revealed a statistically significant increase in total sleep time (TST) by 16.78 min (95% CI = 0.67 to 32.89) and a decrease in wake after sleep onset (WASO) by -12.91 min (95% CI = -25.62 to -0.20) by LT.

Conclusion: The preliminary results of the study suggest that LT has some efficacy in improving sleep quality in insomnia. However, it needs to be validated in future clinical trials with larger samples.