Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Total sleep time
RCT 4-armed trial	61 adults meeting primary insomnia criteria, mean age 63.6 years, range 54 to 78 years	Change from baseline in total sleep time, measured by actigraphy 12 weeks From 412.2 minutes to 384.0 minutes with evening bright light (4000 lux) From 408.0 minutes to 392.6 minutes with morning bright light (4000 lux) From 402.4 minutes to 383.3 minutes with placebo (evening dim light [65 lux]) From 369.8 minutes to 365.2 minutes with placebo (morning dim light [65 lux])	Between-group P values not reported Reported as not significant		Not significant
RCT 4-armed trial	61 adults meeting primary insomnia criteria, mean age 63.6 years, range 54 to 78 years	Change from baseline in total sleep time, measured by polysomnography 12 weeks From 361.3 minutes to 353.3 minutes with evening bright light (4000 lux) From 336.3 minutes to 345.5 minutes with morning bright light (4000 lux) From 364.3 minutes to 358.9 minutes with placebo (evening dim light [65 lux]) From 320.7 minutes to 320.0 minutes with placebo (morning dim light [65 lux])	Between-group P values not reported Reported as not significant		Not significant
RCT 4-armed trial	61 adults meeting primary insomnia criteria, mean age 63.6 years, range 54 to 78 years	Change from baseline in total sleep time, subjective measure 12 weeks From 340.9 minutes to 380.3 minutes with evening bright light (4000 lux) From 339.2 minutes to 367.5 minutes with morning bright light (4000 lux) From 345.8 minutes to 378.9 minutes with placebo (evening dim light [65 lux]) From 320.6 minutes to 291.1 minutes with placebo (morning dim light [65 lux])	Between-group P values not reported Reported as not significant		Not significant
Wake after sleep onset (WASO)
RCT 4-armed trial	61 adults meeting primary insomnia criteria, mean age 63.6 years, range 54 to 78 years	Change from baseline in WASO, measured by actigraphy 12 weeks From 57.2 minutes to 52.1 minutes with evening bright light (4000 lux) From 66.2 minutes to 55.7 minutes with morning bright light (4000 lux) From 54.7 minutes to 65.6 minutes with placebo (evening dim light [65 lux]) From 61.3 minutes to 63.0 minutes with placebo (morning dim light [65 lux])	Between-group P values not reported Reported as not significant		Not significant
RCT 4-armed trial	61 adults meeting primary insomnia criteria, mean age 63.6 years, range 54 to 78 years	Change from baseline in WASO, measured by polysomnography 12 weeks From 77.8 minutes to 64.5 minutes with evening bright light (4000 lux) From 88.8 minutes to 86.4 minutes with morning bright light (4000 lux) From 73.4 minutes to 64.7 minutes with placebo (evening dim light [65 lux]) From 82.9 minutes to 68.2 minutes with placebo (morning dim light [65 lux])	Between-group P values not reported Reported as not significant		Not significant
RCT 4-armed trial	61 adults meeting primary insomnia criteria, mean age 63.6 years, range 54 to 78 years	Change from baseline in WASO, subjective measure 12 weeks From 63.8 minutes to 30.8 minutes with evening bright light (4000 lux) From 74.0 minutes to 48.9 minutes with morning bright light (4000 lux) From 65.2 minutes to 55.6 minutes with placebo (evening dim light [65 lux]) From 69.5 minutes to 63.3 minutes with placebo (morning dim light [65 lux])	Between-group P values not reported Reported as not significant		Not significant
Sleep efficiency
RCT 4-armed trial	61 adults meeting primary insomnia criteria, mean age 63.6 years, range 54 to 78 years	Change from baseline in sleep efficiency %, measured by actigraphy 12 weeks From 80.1% to 79.8% with evening bright light (4000 lux) From 80.6% to 82.4% with morning bright light (4000 lux) From 82.3% to 77.8% with placebo (evening dim light [65 lux]) From 78.9% to 76.7% with placebo (morning dim light [65 lux])	Between-group P values not reported Reported as not significant		Not significant
RCT 4-armed trial	61 adults meeting primary insomnia criteria, mean age 63.6 years, range 54 to 78 years	Change from baseline in sleep efficiency %, measured by polysomnography 12 weeks From 76.8% to 78.2% with evening bright light (4000 lux) From 72.5% to 74.3% with morning bright light (4000 lux) From 75.9% to 76.5% with placebo (evening dim light [65 lux]) From 72.2% to 74.1% with placebo (morning dim light [65 lux])	Between-group P values not reported Reported as not significant		Not significant
RCT 4-armed trial	61 adults meeting primary insomnia criteria, mean age 63.6 years, range 54 to 78 years	Change from baseline in sleep efficiency %, subjective measure 12 weeks From 67.4% to 79.5% with evening bright light (4000 lux) From 66.8% to 77.0% with morning bright light (4000 lux) From 71.6% to 76.9% with placebo (evening dim light [65 lux]) From 69.4% to 73.1% with placebo (morning dim light [65 lux])	Between-group P values not reported Reported as not significant		Not significant