Cognitive performance following premature awakening from zolpidem or melatonin induced daytime sleep.
BACKGROUND
The hypnotic zolpidem and the hormone melatonin were evaluated and directly compared for their effects on performance when subjects sleeping under their influence were prematurely awakened from daytime sleep.


METHODS
Non-sleep deprived volunteers (eight men and five women) received single oral doses of 5 or 10 mg melatonin (Mel-5; Mel-10), 10 or 20 mg zolpidem (Zol-10; Zol-20), or placebo immediately before retiring at 13:00. Performance testing and subjective evaluations occurred prior to dosing and following forced awakening at 15:00, 2 h after dosing.


RESULTS
Compared with placebo, on being awakened under Zol-20, significant performance decrements were prevalent on 9 of 10 cognitive tasks, including grammatical reasoning, mathematical processing, and word memory. Recovery required up to 6 h post-awakening for the more complex tasks. Loss of coordination and nausea were also present on awakening under Zol-20. On being awakened under Zol-10, significant but relatively less severe and shorter duration performance decrements occurred for 4 of the 10 tasks and recovered by 4 h post-awakening. Under Mel-5 or Mel-10, performance decrements seldom occurred and were considerably less severe, briefer, and less systematic than for zolpidem.


CONCLUSIONS
Findings indicated that when operational personnel sleeping with the aid of either 10 or 20 mg zolpidem are prematurely awakened, it would be prudent to evaluate their general well-being and possible need for assistance prior to their being permitted to depart crew-rest or to perform tasks and duties. In contrast, we found little to no evidence of deteriorated well-being or need for assistance when awakened while sleeping under the influence of melatonin.
Storm
William F
WF
NTI, Inc., Brooks City-Base, TX 78235-5105, USA. william.storm.ctr@brooks.af.mil
Eddy
Douglas R
DR
Welch
Cory B
CB
Hickey
Patrick A
PA
Fischer
Joseph
J
Cardenas
Rebecca
R
D000276:Adjuvants, Immunologic / Q000009:adverse effects; D000328:Adult; D002940:Circadian Rhythm / Q000187:drug effects; D002986:Clinical Trials as Topic; D003071:Cognition / Q000187:drug effects*; D003072:Cognition Disorders / Q000139:chemically induced* / Q000209:etiology; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000009:adverse effects; D008297:Male; D008550:Melatonin / Q000009:adverse effects*; D008568:Memory / Q000187:drug effects; D011187:Posture; D011340:Problem Solving / Q000187:drug effects; D011597:Psychomotor Performance / Q000187:drug effects*; D011725:Pyridines / Q000009:adverse effects*; D011930:Reaction Time / Q000187:drug effects; D012890:Sleep / Q000187:drug effects*; D012893:Sleep Wake Disorders / Q000150:complications*; D013997:Time Factors; D014851:Wakefulness / Q000187:drug effects*; D000077334:Zolpidem
D000276:Adjuvants, Immunologic; D006993:Hypnotics and Sedatives; D011725:Pyridines; D000077334:Zolpidem; D008550:Melatonin