Individual Differences in the Sedating Effects of Ethanol

Abstract

Twenty-four healthy, normal-sleeping, males aged 21-35 were screened for basal levels of sleepiness using the Multiple Sleep Latency Test (MSLT). Twelve subjects had basal average daily sleep latencies of less than or equal to 6 min (sleepy) and 12 had latencies of greater than or equal to 16 min (alert) on the MSLT. Subjects consumed either ethanol (0.75 mg/kg) or placebo at 0900-0930 after spending 8 hr time in bed (TIB) the previous night. Sleep latency was measured at 1000, 1200, 1400, and 1600 hr. Divided attention performance and the Stanford Sleepiness Scale (SSS) were assessed at 1100 hr. Breath ethanol concentration (BEC) was determined prior to each latency test. Ethanol decreased average daily sleep latency, divided attention scores and SSS ratings. There were individual differences in the sedating and impairing effects of ethanol, related to subjects' basal level of sleepiness/alertness. The alert subjects exhibited longer sleep latencies and higher performance scores after ethanol administration than the sleepy subjects after placebo. Subjectively the groups had a similar level of sleepiness on placebo and were similarly sedated with ethanol.

Individual Differences in Adult Human Sleep and Wakefulness: Leitmotif for a Research Agenda

“…In a series of studies extending the seminal work of Carskadon and Dement, 79 Roth, Roehrs, and colleagues compared sleepy subjects with alert ones. [80][81][82][83][84][85][86] To define sleepiness/alertness, they utilized the natural variability in average sleep latencies on the Multiple Sleep Latency Test (MSLT), 87,88 for which they found high test-retest reliability. 89 In a group of 176 healthy normals, it was observed that MSLT scores (ie, average sleep latencies) were normally distributed, with a mean score of 11.1 minutes.…”

“…The most extreme 20% of subjects on either side of the distribution had MSLT scores of 6 minutes or less and 16 minutes or morethese were called "sleepy" and "alert" subjects, respectively. Subsequent studies have yielded a variety of experimental results concerning daytime cognitive performance, 81 sleep laten-cy and sleep efficiency in nocturnal PSG, 81 auditory awakening thresholds, 86 sleep efficiency after a 4-hour advance of the nocturnal sleep period 84 and following sleep extension for 14 days, 85 and MSLT scores after a sedative alcohol challenge 82 and following sleep extension for 6 days. 80 All findings appeared to be consistent with the hypothesis that sleepy subjects were chronically sleep deprived, 90 so that the difference between sleepy and alert subjects would lie in a (potentially state-specific) difference in sleep history.…”

Genetics of Narcolepsy and Other Sleep Disorders

“…Indeed, as of today, LS and SS animals have not been studied for sleep and circadian rhythms, whether by use of either polygraphic recordings or wheel-running activity. Moreover, the effect of benzodiazepines and alcohol on sleep seems to be indirect and very dependent on previously accumulated sleep debt (Roehrs et al 1989;Zwyghuizen-Doorenbos et al 1990;Edgar et al 1991;Mignot et al 1992). A better analysis of the sleep and circadian physiology of these model animals during baseline conditions and after deprivation will be needed.…”