Early morning melatonin administration impairs psychomotor vigilance.
The acute soporific effect of melatonin in humans has been demonstrated in a range of studies. How alertness and performance are changed after melatonin given in the morning is not yet known. In a double-blind, placebo-controlled study of nine healthy young men, melatonin was given at 0700 h under controlled conditions of a modified constant routine protocol lasting 56 h (2 days, 3 nights with sleep). A clear decrement in neurobehavioral functions as measured by the Psychomotor Vigilance Test lasted for 6 h after melatonin administration (particularly in the lapse domain and median of the reaction time) without any effect on a letter cancellation task. A subjective soporific effect was present but less pronounced. Thus, melatonin taken in the morning requires caution in situations where high attention is needed.
Centre for Chronobiology, Psychiatric University Clinic, Wilhelm Klein Strasse, 27, 4025 Basel, Switzerland. peter.graw@pukbasel.ch
P
P
Graw
E
E
Werth
K
K
Kräuchi
F
F
Gutzwiller
C
C
Cajochen
A
A
Wirz-Justice
D000328:Adult; D001288:Attention / Q000187:drug effects*; D002940:Circadian Rhythm / Q000187:drug effects*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D006801:Humans; D008297:Male; D008550:Melatonin / Q000008:administration & dosage*; D011597:Psychomotor Performance / Q000187:drug effects*; D011930:Reaction Time / Q000187:drug effects; D012890:Sleep / Q000187:drug effects; D014851:Wakefulness / Q000187:drug effects
D008550:Melatonin