Light therapy in non-seasonal depression: An update meta-analysis.

The effect of light therapy in treating seasonal affective disorder has been demonstrated amongst previous studies. However, the effect of light therapy in treating non-seasonal depression remains unclear. This meta-analysis aimed to determine the efficacy of light therapy in non-seasonal depression. We searched for randomized controlled trials (RCTs) in the PubMed, Web of Science, Chinese National Knowledge Infrastructure, and Chinese Biomedical Database up to February 2020. The pooled post-trial standardized mean difference in depression scores with corresponding 95% confidence intervals was calculated to evaluate the efficacy of light therapy in non-seasonal depression. A total of 23 RCTs with 1120 participants were included. The meta-analysis demonstrated the light therapy was significantly more effective than comparative treatments. Subgroup analyses revealed that none of the factors explained the significantly heterogeneity. Light therapy has a statistically significant mild to moderate treatment effect in reducing depressive symptoms, can be used as a clinical therapy in treating non-seasonal depression. But the quality of evidence is still low, more well-designed studies with larger sample size and high quality are needed to confirm the efficiency of light therapy in treating non-seasonal depression.