EFFECTS OF ETHANOL ON CONTROL OF ATTENTION

In order to investigate the effect of ethanol on visual attention, 18 subjects aged 20-50 years took part in a three-period crossover study in which they received placebo (PL) and two doses of ethanol in random order. The higher dose (E2: 0.88 g/kg, maximum 66 g for males, 55 g f or females) was calculated to produce blood ethanol concentrations of 60-80 mg/100 ml. The lower dose (El) was 75 per cent of E2. Subjects s howed highly significant subjective drunkenness at both doses (p < 0.0 1) and on the higher dose were slowed by 6-11 per cent on most speeded measures, in agreement with previous results. In a Four-Choice Reacti on-Time Task, subjects responded for part of the time to a fixed, repe titive sequence, and at other times to a random sequence of stimuli. A t the transition from repetitive to random sequences, subjects on etha nol showed a disproportionate slowing (60 per cent on the higher dose) . This slowing may be of particular relevance to driving, as the time taken to engage control processing after a period of relatively automa tic activity may be important in dealing with unexpected events on the road. (C) 1997 by John Wiley & Sons, Ltd.