Sumaya 2001.

Methods	Design: three group, three period, cross‐over trial Purpose: examine the effect of bright light treatment on depression in institutionalised older adults
Participants	Patients: institutionalised older adults with moderate to severe depression (baseline scores on the Geriatric Depression Scale 11 to 20) Baseline comparability: not relevant
Interventions	Placebo: sessions with light treatment with 300 Lux for 30 minutes per day for 1 week Untreated: no light treatment Experimental: light treatment with 10,000 Lux (Co‐intervention: NS)
Outcomes	Geriatric Depression Scale at day 5 of each treatment period
Notes	The outcome data was not available from the first period only, and was calculated as deriving from a parallel group trial.
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation?	Unclear risk	NS
Allocation concealment?	Unclear risk	NS
Blinding? Treatment provider	Unclear risk	NS
Blinding? Outcome assessor	Unclear risk	NS
Incomplete outcome data addressed? All outcomes	Low risk	Drop‐out < 15%
Free of selective reporting?	Unclear risk	No protocol available
Free of other bias?	Unclear risk	The outcome data from this cross‐over trial was not available from the first period only, and was calculated as deriving from a parallel group trial.
No signs of variance inequality or skewness?	Low risk	No variance inequality (F‐test not statistically significant) and no skewness (1.64 standard deviations does not exceed the mean)
Trial size > 49?	High risk	N = 20
Clearly concealed allocation + trial size > 49 + drop‐out max 15%	High risk	Trial size < 49