Effectiveness of visible light for seasonal affective disorder: A systematic review and network meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and network meta-analysis of randomized controlled trials
PubMed 40629637 · doi:10.1097/MD.0000000000043107
What was done
Researchers conducted a systematic review and network meta-analysis searching nine databases (PubMed, Embase, Cochrane Library, Scopus, Web of Science, CNKI, Wanfang, VIP, and China Biomedical Literature) through November 12, 2024. They included randomized controlled trials evaluating visible light interventions (white, blue, green, and red light) for seasonal affective disorder (SAD) or winter depression. Data extraction and screening were conducted independently by two researchers.
What was found
The meta-analysis included 17 randomized controlled trials comprising 773 patients (14 trials evaluated white light, 6 blue light, 2 green light, and 5 red light). For alleviating seasonal mood dysregulation or typical depressive symptoms, white light was the most effective, followed by green light, blue light, and red light. Usual care was more effective than green light therapy. The abstract reports no numerical effect sizes, relative risk/odds ratios, ranking metrics, or confidence intervals.
Why it matters
This review directly and indirectly compares different visible light spectra, supporting broad-spectrum white light as the primary evidence-based light modality for treating seasonal depression over narrower visible wavelengths.
Limits
The abstract presents ranking order without reporting point estimates, confidence intervals, or network consistency values. Sample sizes for specific wavelengths were very small (such as green light with only 2 studies). Parameters like light intensity, duration of exposure, device type, and follow-up duration are not detailed in the abstract.
Cited by
- supports Morning exposure to 10,000 lux artificial light can help alleviate seasonal depression and stimulate morning cortisol spikes.