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, an d 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 medi cine 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. Su bjects were randomized to receive either melatonin 1 mg or placebo, 30 to 6 0 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 wer e 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 Scal e (SSS) were also used to quantify nighttime mood and sleepiness. Results: Among the 19 volunteers studied, there was no difference in sleep efficienc y (91.16% vs 90.98%, NS), sleep duration (379.6 min vs 342.7 min, NS), or s leep latency (7.59 min vs 6.80 min, NS), between melatonin and placebo, res pectively. In addition, neither the POMS total mood disturbance (5.769 base line 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 diff erence in nighttime mood and sleepiness between melatonin and placebo. Conc lusions: There are no beneficial effects of a l-mg melatonin dose on sleep quality, alertness, or mood state during night shift work among EM resident s.