Summary of findings 4. Bright white light therapy compared with infrared light therapy for prevention of SAD.
| Bright white light therapy compared with infrared light therapy for prevention of SAD | ||||||
| Patient or population: all participants were known SAD patients who had been successfully treated with conventional light therapy in previous winters Settings: outpatient field study; participants chose when (between 6 am and 9 am) and where they would use the visors Intervention: bright white light therapy Comparison: infrared light therapy | ||||||
| Outcomes | Risk in both groups | Relative effect (95% CI) | Number of participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Risk in this treatment group | Risk in this treatment group | |||||
| Infrared light therapy | Bright white light therapy | |||||
| Incidence of SAD (SIGH‐SAD score ≥ 20) (follow‐up 26 weeks) |
Study population | RR 1.29 (0.50 to 3.28) | 29 (1 RCT) | ⊕⊝⊝⊝ Very lowa,b | ||
| 333 per 1000 | 357 per 1000 | |||||
| Incidence of severe SAD (SIGH‐SAD‐SR (≥ 40)) (follow‐up 26 weeks) |
Study population | RR 1.07 (0.07 to 15.54) | 29 (1 RCT) | ⊕⊝⊝⊝ Very lowa,b | ||
| 67 per 1000 | 71 per 1000 | |||||
| Overall discontinuation (follow‐up 26 weeks) |
Study population | RR 1.33 (0.35 to 5.13) | 36 (1 RCT) | ⊕⊝⊝⊝ Very lowa,b | ||
| 167 per 1000 | 222 per 1000 | |||||
| CI: confidence interval; RCT: randomised controlled trial; RR: risk ratio; SIGH‐SAD‐SR: Structured Interview Guide for the Hamilton Depression Rating Scale‐Seasonal Affective Disorders self‐rating version | ||||||
| GRADE Working Group grades of evidence High quality: further research is very unlikely to change our confidence in the estimate of effect Moderate quality: further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate Low quality: further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate Very low quality: we are very uncertain about the estimate | ||||||
aDowngraded two levels because of severe risk of bias due to non‐blinding and unclear randomisation process and allocation concealment; no intention‐to‐treat analysis was reported, outcomes were self‐rated, compliance throughout study duration was not checked and participant characteristics were not reported comprehensively. bDowngraded one level because of small sample size (lack of power and random error could have influenced results).