James 1998.

Methods	Trial design: Double blind single dose randomised cross‐over trial Country: Michigan, USA Randomisation procedure: Trough computer randomisation schedule; medication was identified only by sequential number; identification key was kept by a hospital pharmacist and seen by investigators only at the termination of the trial
Participants	Inclusion: Trial included 24 adult volunteers. The volunteers were pre‐hospital personnel (EMTs or paramedics) working rotating night shifts with the Kent County EMS system. Number randomised: 24 volunteers initially enrolled in the trial (1 excluded due tranquillizer use, 1 pregnant) Followed‐up: 22 volunteers Lost to follow‐up: 2 volunteers Age: mean 29 ± 8 (SD) Sex: intervention female/male 5/17 Exclusion: 1 tranquillizer use, 1 pregnant
Interventions	Trial intervention: Melatonin 6 mg once after three to six consecutive night shifts Comparison intervention: Placebo Treatment frequency and duration: Melatonin 6 mg one capsule orally 30 minutes before each consecutive day sleep, latest at 11 o'clock; total of four treatment cycles (2 melatonin, 2 placebo) six weeks; four visits and one telephone call during the trial period.
Outcomes	Sleep length, sleep onset and quality while off work: Sleep latency (time between bedtime and sleep onset), reported awakenings during sleep, sleep efficiency (total time asleep as a percentage of total time in bed), total sleep time and duration of daytime naps. Sleep quality was measured using a linear VAS, ranging from worst (score = 0) to best (score = 10). Cognitive performance, sleepiness and fatigue at work: The participant's mood during each post‐treatment night was measured using three bipolar VASs: alert to tired, calm to tense, and cheerful to depressed. Job performance on night shifts was measured using three monopolar VASs "demands on your time" (time pressure), "mental effort or concentration" (mental load), and "stress or emotional involvement". Linear analog scores were measured to the nearest millimetre (P. 368).
Notes	‐
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"After giving informed consent, volunteers were randomly assigned to take either a 6 mg melatonin capsule (Vitamin Research Products Inc., Carson City, Nevada) or placebo. Randomization was accomplished using a computer randomisation schedule" (P. 367).
Allocation concealment (selection bias)	Low risk	See above and below.
Blinding of participants All outcomes	Low risk	Trial medications were packaged in blister packs and identified only by a sequential number for computer coding purposes. The identification key was kept by a hospital pharmacist and seen by investigators only at the termination of the trial (P. 367).
Blinding of care providers	Low risk	See above.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	See above.
Incomplete outcome data (attrition bias) All outcomes	Low risk	A total of 24 volunteers were initially enrolled in the trial. One participant was excluded because of prescription tranquillizer use. Another paramedic became pregnant and dropped out of the trial after completing one treatment cycle (melatonin).
Outcome measured with validated instrument All outcomes	Low risk	Sleep length and quality: Total sleep time; Sleep onset latency.Sleep quality was measured using a linear VAS, ranging from worst (score = 0) to best (score = 10). Cognitive performance, sleepiness and fatigue at work: The participant's mood during each posttreatment night was measured using three bipolar VASs: alert to tired, calm to tense, and cheerful to depressed. Job performance on night shifts was measured using three monopolar VASs "demands on your time" (time pressure), "mental effort or concentration" (mental load), and "stress or emotional involvement. '' Linear analog scores were measured to the nearest millimetre (P 368).
Selective reporting (reporting bias)	Unclear risk	Outcomes only partially reported.
Other bias	Low risk	Balance in baseline characteristics: Cross‐over design balances baseline characteristics Balance in interventions: Low discontinuation Funding public/private: No data