ELECTROPHYSIOLOGICAL ASSESSMENT (THE MULTIPLE SLEEP LATENCY TEST) OF THE BIPHASIC EFFECTS OF ETHANOL IN HUMANS

The Multiple Sleep Latency Test (MSLT) was used to assess the effects of ethanol at the peak and descending phases of the breath ethanol cur ve. Ethanol (0.75 g/kg) was administered (at 0900 hr) to 8 healthy, no rmal-sleeping men, aged 21 to 45 years old after 8 hr of sleep the pre vious night. MSLTs were conducted and breath ethanol concentrations (B rECs) were measured at 15, 45, 75, 105, 225, and 345 min after drinkin g was completed. Subjective measures were administered immediately bef ore each sleep latency test. BrECs over the first 75 min (tests 1 to 3 ) peaked and differed from all subsequent tests (tests 4 to 6) over wh ich BrECs declined. Sleep latency and subjective measures were average d over tests 1 to 3 and 4 to 6. There was a significant increase in me an sleep latency relative to placebo for tests 1 to 3 and a significan t reduction for tests 4 to 6. The subjective measure of stimulation se dation, the Biphasic Alcohol Effects Scale, showed lessened sedation a fter ethanol versus placebo on tests 1 to 3, compared with tests 4 to 6. This study confirmed the presence of a biphasic ethanol effect usin g an electrophysiological method (MSLT), showing increased physiologic al alertness on the peak phase of the BrEC curve and increased sedatio n on the descending phase. Relative to the effects observed on the MSL T with other low-dose stimulant drugs, the stimulatory effect of ethan ol was mild.