Light Treatment for PTSD: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis evaluated the efficacy of light therapy in reducing PTSD symptoms across six randomized controlled trials (RCTs), including 312 participants. Standardized mean differences (SMDs) were calculated, revealing a large pooled effect of 1.21 (95% CI: 1.04, 1.39, p < 0.001), with low to moderate heterogeneity (I² = 28.3%, p = 0.23). Subgroup analyses by intervention type—blue light vs. amber light (SMD = 1.27), bright light vs. sham/dim light (SMD = 1.19), and white/green light vs. other controls (SMD = 1.14), showed consistent substantial effects, with no significant differences between subgroups (p = 0.68). Sensitivity analyses excluding high-risk studies confirmed robustness (SMD = 1.15, 95% CI: 0.95, 1.36). Funnel plot symmetry and Egger’s test (p = 0.45) indicated no publication bias. Light therapy improved objective sleep metrics and depressive symptoms, suggesting broader therapeutic potential. Limitations include the small number of studies, variable protocols, and high-income country focus. These findings support light therapy as a promising, non-invasive intervention for PTSD, with minimal adverse effects. Future research should standardize protocols and explore long-term efficacy in diverse populations.