Effect of exogenous melatonin on mood and sleep efficiency in emergency medicine residents working night shifts.
OBJECTIVE
To determine whether melatonin taken prior to attempted daytime sleep sessions will improve daytime sleep quality, nighttime sleepiness, and mood state in emergency medicine (EM) residents, changing from daytime to nighttime work schedules.


METHODS
A prospective, randomized, double-blind crossover design was used in an urban emergency department. Emergency medicine residents who worked two strings of nights, of at least three nights' duration each, and separated by at least one week of days were eligible. Subjects were randomized to receive either melatonin 1 mg or placebo, 30 to 60 minutes prior to their daytime sleep session, for three consecutive days after each night shift. Crossover to the other agent occurred during their subsequent night shifts. Objective measures of quality of daytime sleep were obtained using the Actigraph 1000. This device measures sleep motion and correlates with sleep efficiency, total sleep time, time in bed, and sleep latency. The Profile of Mood States (POMS) and the Stanford Sleepiness Scale (SSS) were also used to quantify nighttime mood and sleepiness.


RESULTS
Among the 19 volunteers studied, there was no difference in sleep efficiency (91.16% vs 90.98%, NS), sleep duration (379.6 min vs 342.7 min, NS), or sleep latency (7.59 min vs 6.80 min, NS), between melatonin and placebo, respectively. In addition, neither the POMS total mood disturbance (5.769 baseline vs 12.212 melatonin vs 5.585 placebo, NS) nor the SSS (1.8846 baseline vs 2.2571 melatonin vs 2.1282 placebo, NS) demonstrated a statistical difference in nighttime mood and sleepiness between melatonin and placebo.


CONCLUSIONS
There are no beneficial effects of a 1-mg melatonin dose on sleep quality, alertness, or mood state during night shift work among EM residents.
Jockovich
M
M
Department of Emergency Medicine, University of Florida Health Science Center, Jacksonville 32209, USA.
Cosentino
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D
Cosentino
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L
Wears
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RL
Seaberg
D C
DC
D000328:Adult; D000339:Affect / Q000187:drug effects*; D000704:Analysis of Variance; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004635:Emergency Medicine; D005260:Female; D006801:Humans; D007396:Internship and Residency; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D012890:Sleep / Q000187:drug effects*
D008550:Melatonin