Cavallo 2005.

Methods	Trial design: Double‐blind, randomised, placebo‐controlled cross‐over trial Country: Cincinnati, Ohio, USA Work settings: Pediatric residents in night work 11 to 12 nights over a two‐week period Randomisation procedure: Drug pharmacist used simple randomizations
Participants	Inclusion: Healthy second‐year paediatric residents working two night float rotations which is a total of 11 to 12 days when residents have the inverted activity‐sleep schedule distributed over a two‐week period. Number randomised: Screened, randomised, followed‐up 45 Lost to follow‐up: 28 completed two arms of the trial, 17 completed only one arm of the trial (7 melatonin, 10 placebo) (total of 73 trial periods, 35 melatonin, 38 placebo). Age mean: 28.6 ± 1.9 Sex: Intervention male 16/45 and control male 16/45 Exclusion: No alcohol or sedative during the trial period, infants or toddlers in household, chronic illness, depression.
Interventions	Trial intervention: Melatonin 3 mg in gelatin capsule Comparison intervention: Placebo Treatment providers: Hospital's investigational drug pharmacist Treatment frequency and duration: Participants took melatonin (3 mg) or a placebo before bedtime in the morning after night shift (not later than 13.00)
Outcomes	Sleep length, sleep onset and quality while off work: Sleep duration, sleep quality, number of awakenings (diary) Cognitive performance, sleepiness and fatigue at work: Conners Continuous performance test, Profile of Mood States (POMS).
Notes	Ethics: The Institutional Review Board approved the trial
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	The hospital’s investigational drug pharmacist used simple randomizations with no restriction and prepared gelatin capsules of melatonin and placebo that were identical in appearance.
Allocation concealment (selection bias)	Low risk	The pharmacist dispensed the capsules in a regular medication container for the first eight participants and in a container fitted with an automated medication monitoring event system (track cap) for all subsequent participants to monitor compliance with treatment. For a total of 676 treatment days with capsules dispensed in track caps, there were 661 track cap data points and 660 diary data points.
Blinding of participants All outcomes	Low risk	See above, estimated.
Blinding of care providers	Unclear risk	No data.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No data.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Of these 45 residents, 28 participated in the trial during the two night float rotations, completing the two treatment arms of the cross‐over design. The other 17 residents completed only one treatment arm: seven were assigned to take melatonin and 10 were assigned to take placebo.
Outcome measured with validated instrument All outcomes	Low risk	Sleep length, sleep onset and quality while off work: Sleep duration, sleep quality, number of awakenings (diary). Cognitive performance, sleepiness and fatigue at work: Conners Continuous performance test, POMS.
Selective reporting (reporting bias)	Low risk	Not detected, (see attrition bias); individual observations summed.
Other bias	Low risk	Balance in baseline characteristics: Cross‐over design, good balance in baseline characteristics. Balance in interventions: Good balance in interventions, few withdrawals from the trial Funding public/private: No data.